NANOSTRUCTURED MULTIFUNCTIONAL
MATERIALS
“POLITEHNICA” UNIVERSITY OF TIMISOARA
Sinaia, Romania, October 18-20, 2007
BOOK OF ABSTRACTS
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1st Conference NANOSTRUCTURED MULTIFUNCTIONAL MATERIALS
Sinaia, Romania, October 18 – 20, 2007
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WELCOME REMARKS
On behalf of the Organizing Committee I would like to
welcome you to the 1st National Conference ”Nanostructured
Multifunctional Materials” (NMM07), with international participation.
The event is organized by the “Al.I.Cuza” University of
Iasi - Romania, Faculty of Chemistry, Laboratory of Materials
Chemistry, under the auspices of the Research Excellence
Programme CEEX initiated by the Romania's Ministry of Education
and Research.
Also, the 1st Conference”Nanostructured Multifunctional
Materials” is included as an important event in the Programme of
“Al.I.Cuza University Days’-2007”.
The Conference is aimed at promoting the fundamental and
applied studies of nanostructured multifunctional materials. The
scientific program will consist of plenary and keynote lectures, and
oral and poster presentations.
Many of key topics impacting on nanostructured materials
will be addressed by our colleagues over the next two days and we
are sure that all of you will be involved in many discussions to
make this event more productive and having in mind that the
nanostructured multifunctional materials are key for “high tech”
strategic materials.
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The event brings together experts in the field of
nanomaterials to present and discuss their research and
development work and serve as a stimulus for increased
collaborations among the researchers for solving important national
issues associated with multifunctional nanostructured materials.
Another equally important objective is to attract today’s students who
will carry on the task of solving issues into the next period.
The Conference will provide the opportunity for developing
new scientific collaboration and represents an important meeting
for those who are interested to share and disseminate their
experience, knowledge and innovative ideas on nanostructured
materials.
The feedback from YOU is very important for planning the
next conference in 2011, to which You are invited.
Conference Chairman,
Prof.univ.dr.Evelini Popovici
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Honorific Committee
Prof.dr.eng.Ecaterina ANDRONESCU - „Politehnica” University,
Bucharest, Romania
Prof.dr.eng.Corneliu TRISCA-RUSU - Executive Manager,
MATNANTECH, Bucharest, Romania
Prof.dr.Etienne.F. VANSANT - Antwerpen University, Belgium
Prof.dr.Pegie COOL - Antwerpen University, Belgium
Prof.dr.Panagiotis MISAELIDIS - Aristotle University, Thessaloniky,
Greece
Prof.dr.Gheorghe BREZEANU - „Politehnica” University,
Bucharest, Romania
Prof.dr.Alfonso NASTRO - Callabria University, Italy
Prof.dr.Nicolaie NAUM - Manager ANCS, Bucharest, Romania
Dr.eng.Doru PUSCASU - Scientific Manager - CEPROCIM,
Bucharest, Romania
Prof.dr.Vasile PARVULESCU - University of Bucharest, Romania
Prof.dr.eng. Vasile Ababi - “Gh.Asachi” Technical University, Iasi,
Romania
Prof.dr.eng.Mihai Cruceanu - „Al. I. Cuza” University, Iasi,
Romania
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Organizing Committee
Prof.univ.dr.Evelini POPOVICI –Chairman Conference Prof.univ.dr.Aurelia VASILE- Co-Chairman Conference
Prof.univ.dr.Gh. POPA, „Al. I. Cuza” University, Iasi, Romania
Prof.univ.dr. N. BILBA, „Al. I. Cuza” University, Iasi, Romania
Prof.univ.dr. Rodica PODE – „Politehnica” University, Timisoara,
Romania
Prof.univ.dr. N. SULITANU, „Al. I. Cuza” University, Iasi, Romania
Assoc.Prof. dr. Maria ALEXANDROAEI, „Al. I. Cuza” University,
Iasi, Romania
Assoc.Prof. dr. Doina HUMELNICU, „Al. I. Cuza” University, Iasi,
Romania
Lecturer dr.I. ASAFTEI, „Al. I. Cuza” University, Iasi, Romania
Secretariat:
Lecturer dr. I. ASAFTEI PhD Student Emiliana DVININOV PhD Student Maria IGNAT PhD Student Elena SEFTEL PhD Student Gina MIHAI PhD Student Claudia HRISTODOR PhD Student Violeta COPCIA PhD Student Camelia LUCHIAN PhD Student Nicoleta TURTA
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CONFERENCE TOPICS
1. NANOSTRUCTURED POROUS MATERIALS 2. ADVANCED MULTIFUNCTIONAL MATERIALS 3. NATURAL AND SYNTHETIC ZEOLITES 4. MESOSTRUCTURED MATERIALS-SYNTHESIS AND
MODIFICATION 5. CATIONIC AND ANIONIC CLAYS 6. INDUSTRIAL AND ENVIRONMENTAL
APPLICATIONS 7. OTHER ASPECTS OF NANOMATERIALS SCIENCE
AND TECHNOLOGY
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PL- 4. What Does ESR Spectroscopy Tell us about Size Dependent Phenomena in NANO Systems ?
L. M. Giurgiu National Institute for Research and Development of Isotopic and Molecular Technologies, P.O.Box 700, Cluj-Napoca, Romania; [email protected]
Electron Spin Resonance (ESR) spectroscopy is well known to be
a powerful tool for studying microscopic details of nanostructured
materials. In the present contribution, the size dependent phenomena as
seen by ESR in NANO systems are reported.
I will concentrate on the following informations revealed by EPR:
(i) metallic and magnetic nanoparticle’s mean size evaluation (ii)
orientation degree of magnetic nanoparticles and (iii) spin dynamics as
function of the grain size reduction in nanostructured colossal
magnetoresistive (CMR) manganites.
The first nano systems under investigations were the conducting
polymer nanocomposites based on polypyrrole (PPy) and iron oxide
magnetic particles and noble metallic nanoparticles. As far as the spin
dynamics in CMR nanoparticles is concerned, the size dependence of the
polaron activation energy and double exchange coupling is analysed.
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PL - 5. Fundamentals of Synthesis Processes of Microporous Materials
E.F. Vansant, P. Cool Laboratory of Adsorption and Catalysis, Department of Chemistry, University of Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium, [email protected]
The presentation gives a review on the synthesis and properties
of microporous (zeolites) and combined micro/meso porous layered
structures.
Since their discovery, more than one century ago, many studies
on microporous zeolites have been carried out. However, attempts to
prepare synthetic zeolites succeeded only in the late 1940’s. Adsorption
and ion exchange properties were soon recognized as their specific
characteristics. The latter result from their structural formula:
x/n Mn+
[ (AlO2)x (SiO2)y ] . w H2O
The framework of zeolites is built of AlO4 and SiO4 tetrahedra linked to
each other by sharing all corner oxygen atoms. The structure contains as
many equivalents of exchangeable cations as there are aluminium atoms
in the framework. As these frameworks are so porous, their interstices
hold not only the cations needed to neutralize the anionic framework
charge but also large amounts of water. As zeolites are crystalline solids,
the pores which are of molecular dimensions, are as regular as the
position of the lattice atoms. The possibility of zeolites to adsorb
molecules of relatively small size over molecules of larger size formed the
basis for the introduction of the term molecular sieves.
Following the history of synthetic zeolites, the first generation of
molecular sieves were synthesized between 1940 – 1950, where zeolites
were formed with low silica to alumina ratios (SiO2/Al2O3 ≤ 10) by
crystallizing reactive aluminosilicate gels with alkali and alkaline earth
metalhydroxides. Representative structures are the zeolites A, X, Y
(faujasites) and mordenite. Such zeolites are characterized by a high ion-
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exchange capacity, an extremely hydrophilic surface and many acid sites
with a wide variety of acid strength. Such frameworks show different
thermal and hydrothermal stability, depending on structural and
compositional factors. In the synthesis of the second generation of
molecular sieves (1960 – 1970) all possible quaternary ammonium ions
were used which resulted in new materials with new structure types and
different chemical compositions. In particular, aluminosilicates with
SiO2/AlO3 ≥ 20 were synthesized (silicalite, ZSM-5, etc.). Furthermore, the
isomorphous substitution of many elements was shown to be possible in
such silica polymorphs, and metallosilicates with zeolitic properties were
generated (Ti -, B - substituted silicalites). The extensive use of organic
amines as structure-directing templates or pore filling agents, coupled with
a new gel chemistry resulted in the discovery of a third generation of
molecular sieves (1982 – 1986), containing Al3+
and P5+
as lattice atoms
(ALPO, SAPO, MeAPSO, ElAPO). This class of materials contains
molecular sieves of known zeolitic structures and new tri- and bi
dimensional structures.
In order to improve the performance of zeolites as molecular sieves,
several chemical modification techniques were developed to vary in a
controlled way the zeolitic pore system: pore size engineering.
In practice, pore size engineering can be the result of
a) modification by cation exchange processes
b) modification by pre adsorption of polar molecules
c) modification of the zeolitic framework
A cation exchange process can enlarge or can reduce the zeolitic pore
openings depending on the size of the cations, cation population and or
resiting of cations, which are normally located near these openings.
Another method for altering the molecular sieving effect of zeolites is the
formation of cationic complexes, caused by a pre adsorption of polar
molecules. However, the most efficient and stable way to change the
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microporosity of zeolites can be achieved by a modification of the zeolitic
framework. This porosity change can be result of:
a) crystallographic changes by thermal treatment
b) internal and external structural modification by
implantation of additional atom groups
c) external surface modification of the zeolite crystal
(coating process)
Porous materials with porosity in the large micro- and small
mesoporous regions can be obtained in the pillared interlayered clays
(PILC). The general concept of pillaring consists of two main steps: first,
the interlamellar small cations are exchanged for other bulky ions (organic
cations, organometal complexes or inorganic polyoxycations). A second
or calcination step converts the inorganic polyoxocation precursors into a
rigid, stable metal oxide pillars, tightly bonded to the clay layers.
When the lateral dimensions of the clay layers are small (≤ 0.05 µm) and
the layer morphology is lath-like, the flocculation of smectite clays by
polyoxocations can lead to delaminated aggregates. The delamination
changes the well-ordered F-to F lamellar structures (∼ 2 µm) into F-to-F
and E-to-F structures. Pillaring these mixed lamellar structures give rise to
both micropores (for F-to-F structures) and mesopores (for E-to-F
structures).
Selected bibliography
1. D.W. Breck, Zeolite Molecular Sieves, Wiley, New York, 1974
2. P.A. Jacobs, Carboniogenic Activity of Zeolites, Elsevier, Amsterdam, 1977.
3. R.M. Barrer, Zeolites and Clay Minerals as Sorbents and Molecular Sieves, Academic Press, London, 1978.
4. G. Gottardi and E. Galli, Natural Zeolites, Springer Verlag, Berlin, 1985.
5. E.F. Vansant, Pore Size Engineering in Zeolites, J. Wiley & Sons, 1990.
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6. W.J. Mortier, Compilation of Extra Framework Sites in Zeolites, Butterworth Scientific Ltd., Guilford, 1982.
7. R. Von Ballmoos, Collection of Simulates XRD Patterns for Zeolites, Butterworth Scientific Ltd., Guilford, 1984.
8. W.M. Meier and D.J. Olson, Atlas of Zeolite Structure Types, Butterworth Scientific Ltd., Sevenoaks, 1988.
9. D.W. Breck, W.G. Eversole, R.M. Milton, T.B. Reed and T.L. Thomas, J. Am. Chem. Soc., 1966, 78, 5963.
10. E.F. Vansant, G. Peeters and I. Michelena, J. Chem. Res., 1978, 90, 1165.
11. R.M. Barrer and L.C.V. Rees, Trans. Far. Soc., 1945, 10, 852
12. M. Niva, S. Kato, T. Hattori and Y. Marakumi, J. Chem. Soc. Faraday Trans. I, 1984, 80, 3135.
13. E.F. Vansant, P. De Bièvre, G. Peeters, A. Thijs and I. Verhaert, Eur. Appl. Res. Rep.-Nucl. Sci. Techn., 1982, 4, 983.
14. P. Cool and E.F. Vansant, Pillared Clays: Preparation, Characterization and Applications, Molecular Sieves, 1998, vol. 1, 265 – 288.
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PL- 6. Novel Synthesis and Activation Strategies Leading to the Formation of Tuned Mesostructures
Pegie Cool, E.F. Vansant Laboratory of Adsorption and Catalysis, Department of Chemistry, University of Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium, [email protected]
The presentation gives a review on the synthesis and properties
of mesoporous materials and mesoporous materials with microporous
characteristics.
Most of the synthesis approaches to form inorganic mesoporous
materials in general are based on the use of organic template molecules
in different assembly processes around which the inorganic precursor can
condense. However, also template free synthesis mechanisms like the
nanobuilding block (NBB) mechanism and other approaches are studied.
A large diversity in synthesis approaches are known for the formation of
different materials but also similar materials (e.g. MCM-48) can be made
by different synthesis methods, each of them allowing other parameters to
be altered and controlled. For this reason, knowledge of the synthesis
methods and parameters that influence the final material will allow pore
size engineering and control of the morphology and structure of the
obtained material. Basically, the synthesis of mesoporous materials and
its control can be limited to the altering of the combination of the chosen
surfactant type, the specific synthesis mechanism and the interaction of
the silica source with the template molecules (see Table 1). For example,
M41S is made by a S+I- direct interaction between an ionic, positively
charged molecular based organized systems (MOS) surfactant and
negatively charged silica source in basic environment. Three types of
mechanisms: fluid crystal template and self-assembly and cooperative
self-assembly processes have been suggested for the synthesis of M41S
materials based on the applied synthesis conditions. SBA materials on the
other hand have been made by use of polymeric based organized
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systems (POS) surfactants that interact through an indirect reaction of the
template with the positively charged silica source (S+X
-I-) in acid medium.
A neutral interaction between MOS surfactants and an inorganic source
results in the formation of e.g. HMS materials (S0I0). Moreover, also other
parameters such as pH, additives (e.g. salts, swelling agents, co-solvents,
co-surfactants, etc.), the concentrations, the silica source, the solvent,
temperature, etc. will allow the fine tuning of the final material due to small
changes in the characteristics of the surfactant, the mechanism or the
interaction.
Table 1: Schematic overview of the main synthesis parameters to
generate a diversity of mesoporous materials.
Surfactant Mechanism
MOS LCT Direct ionic
POS Self-assembly non-ionic
Textural templates Cooperative self-assembly Indirect ionic
Nanometric building blocks non-ionic
Interaction
MOS = molecular based organised systems,
POS = polymeric based organised systems,
LCT = liquid crystal template
Combined micro- and mesoporous materials were claimed to
have advantages compared to the exclusively microporous or
mesoporous materials. They provide improved diffusion rates for transport
in catalytic processes (faster reactions), better hydrothermal stability,
multifunctionality to process a large variety of feedstocks, capabilities of
encapsulating waste in the micropores, controlled leaching rates for a
constant and gradual release of active components etc. Different porous
materials that combine micro- and mesopores have been developed in the
last few years such as SBA-15, PHTS (Plugged Hexagonal Templated
Silica), MAS (Mesoporous Aluminium Silicates), MTS (Mesoporous
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Titanium Silicates), UL-ZSM-5, zeotiles etc. Of which the latter 4 are
mesoporous materials build up from zeolite precursors.
A lot of different approaches for the synthesis of this new
generation of bimodal porous materials have been described in literature.
An overview of the most important synthesis routes is given in Table 2.
Table 2: Overview of the different existing synthesis routes for the
formation of mesoporous materials with zeolite character.
Method mesopore formation zeolite formation
steaming/acid leaching dealumina
tion/
desilication alkaline treatment
full-grown zeolite
with template
with carbon recrystalli
sation
mesoporous
amorphous
silica
structures
with carbonised
template
TPAOH
impregnation and
temperature
increase
carbon
based
mesoporous carbon or inversed
carbon replicas zeolite precursors
deposition large pore silica structures zeolite precursors
templating
approach surfactants zeolite precursors
Furthermore, all these nanoporous materials can be catalytically
activated by the Molecular Designed Dispersion (MDD) technique. In this
way, various depositions of dispersed pure and mixed transition
metaloxide layers on the surface of the mesoporous materials can be
obtained.
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References
1. G.J.A.A. Soler-Illia, C. Sanchez, B. Lebeau, J. patarin, Chem. Rev,
2002, 102, 4093. 2. A. Corma, Chem. Rev., 1997, 97, 2373. 3. Cool P., Vansant E.F., Collart O., Ordered siliceous mesostruc-
tured materials: synthesis and morphology control, Inorganic Chemistry in Focus II/ G. Meyer, D. Naumann, L. Weissmann [edit.], Wiley-VCH Verlag GmbH & Co., Weinheim, 2005, p. 319-346.
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PL- 7. Nanocasting – Powerful Strategy for Nanostructured Porous Materials Design
Eveline Popovici ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi Romania, [email protected]
Nanocasting is a powerful method for creating nanostructured
materials that are more difficult to synthesize by conventional processes.
Structure replication on the nanometer length scale allows materials properties
to be manipulated in a controlled manner, such as tunable composition,
controllable structure and morphology, and specific functionality [1].
The nanocasting needs for the precursor and template materials.
The templates that can be used include followed types, namely soft, hard,
complex templates and biotemplates.
The template must have the controllable morphology and
structure and the ability to remove it without affecting the cast. The
templates should be easily and completely removed by chemical
(leaching, combustion) or physical (thermal treatment) methods to obtain
the true replicas.
The soft lyotropic liquid crystal phases resemble a casting mold in
which the chemical synthesis and precipitation of the inorganic material
takes place without altering the self-assembled structure [2,3].
The soft templates, which can be subsequently removed by heat
treatment, are normally organic-based molecules, supra-molecules, and
molecular associations, such as cationic surfactant micelles, non-ionic
surfactants, amines, amphiphilic block copolymers polymers [4], cationic
and anionic polyelectrolyte blocks [5], poly(styrene)–PEO block-
copolymers of low molecular weight [6], large variety of polymers like
poly(ethylene oxide), poly(methyl methacrylate) [7], poly(vinyl alcohols),
poly(vinyl acetate) [8].
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Additionally, vesicles, ionic liquids, self-assembled colloidal
crystals, and air bubbles that can be considered as soft templates have
also been used to prepare various porous materials [1,9].
Such soft templates have been employed in synthesizing microporous
zeolites and ordered mesoporous molecular sieves (Fig.1) [10-20].
In recent synthesis, instead of organic amines or surfactants,
highly ordered mesoporous silicates are employed as templates, which
are considered as hard templates.
The hard template method has recently been employed to
fabricate various novel porous structures, which are difficult to synthesize
using the soft template method.
The nanocasting pathway with hard templates opens the door to
the design of highly porous solids with multifunctional properties and
interesting application perspectives [2].
Fig.1. Schematic representation of the nanocasting concept. using soft template [10].
Microporous zeolites [22], ordered mesoporous silicas (e.g.,
MCM-48 [23], SBA-15 [24], and SBA-16 [25]), ordered mesoporous
carbon,[10] and anodic alumina membranes with micro- and sub-
micrometre pores [16] have been used to fabricate microporous,
mesoporous and macroporous carbons, various porous metals and metal
oxides , metal sulfide and polymer replica mesostructures with unique
catalytic, sensoring, and electronic properties.
The hard template refers to porous solids. One of the most
versatile hard templates is ordered mesoporous silica, since it can be
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prepared in shapes as diverse as spherical, fibrous, rodlike, and even with
chiral morphologies [2].
The pore structures of these parent materials can be transferred
to the solid structure of the generated porous materials, while the walls of
the parent become the voids of the replica.
Upon heat treatment, the precursors are thermally decomposed,
and the nanoparticles derived grow larger and larger by interconnection to
each other combined with a crystallization process. If the loading rate of
the precursors is high enough, during the annealing process, the
nanocrystals may interlink with each other and form continuous
frameworks.
After the templates of the mesoporous silicates are destroyed, the
mesostructures are fully copied by the nanocrystals, and replica materials
are obtained.
Nanocasting strategy with hard template involves two main
steps: provision of a suitable template, and the casting step.
In the first step, the template pores impregnation with a precursor
of the desired compound takes place. The precursors can be incorporated
into the channels of mesoporous silicates by sorption, phase transition,
ion exchange, complex or covalent grafting. The precursor must enter the
template structure; it must either be gaseous, highly soluble, or liquid at
moderate conditions, so that it can be infiltrated into the voids of the
template while achieving sufficiently high loadings.
The casting step starts by a heat treatment under controlled
atmosphere of the impregnated template, by which the infiltrated
precursor is converted into the inorganic material. This step is followed by
the template removal. The template moving off step implies the template
dissolution (when the template mesostructures are fully copied by the
nanocrystals and replica materials are obtained) or heat treatment with
thermally template decomposition (when the derived nanoparticles grow
larger and larger by interconnection to each other combined with a
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crystallization process). Generally, the bioproducts leave the channels in
the gas phase [3].
Fig.2. Nanocasting routes for the preparation of nanoparticles and
nanostructured inorganic materials.
In the casting step, since the synthesis takes place in a confined
nanospace, the sintering of the particles is restricted and the
nanostructures or nanoparticles obtainment is achieved. The structure of
the synthesized compounds can be tailored depending on the pore
characteristics of the selected template.
When the template consists of a fully continuous solid phase and
a continuous porous system (for instance activated carbons, silica gels,
mesostructured silica), the obtained material may retain a 3D structure
containing framework-confined pores. In this case, the product is an
inverse replica of the template structure and may be referred to as a
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nanostructured material. The filling degree of the porosity of the template
by the precursor must be sufficiently high.
When the template porosity is made up of non-connected pores
(anodic aluminum oxide membranes, MCM-41 silica) will produce solid
without framework-confined pores, made up of small particles (<100nm)
and may be referred to as nanoparticulate material.
During the impregnation process, the precursors tend to be
absorbed at the external surface of the templates and the mesopore
channels are fairly difficult to fill completely. Besides, the driving force for
promoting the movement of the precursors into the mesopores is the
capillary effect, and a weak interaction between the silicate walls and the
precursors may decrease the capillary function and cause the precursors
to remain outside the mesopores and/or stick inside the mesopore
channels and/or lock the channels.
The interactions between the silicate walls and the precursors are
determined by several complicated factors: hydrogen bonding;
coordination bonding; Van der Waals forces.
Carbon replicas from microporous materials such as zeolites have
also been synthesized. The first zeolite replica with a well resolved X ray
diffraction pattern was obtained by Patarin and colab [32].
Nanocasting, using highly ordered mesoporous silica as a
template, has brought forward incredible possibilities in preparing novel
mesostructured materials, and has led to a great number of ordered
nanowire arrays with small diameter (<10 nm), large surface areas (up to
2500 m2 g
–1) and uniform mesopores (1.5–10 nm), with tunable 2-D or 3-D
mesostructures and controlled morphology such as spheres, rods, films,
and monoliths; and different components including carbon, metals, metal
oxides and metal sulfides.
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Fig. 3. Some zeolites used as hard template and the representation of the carbon
materials prepared from them [ 31 ].
Fig.4. Schematic illustration of nanocasting preparation of the carbon nanocage [33].
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Fig. 5. Schematic representation of the framework structure of SBA-15 and
replication to platinum nanostructures [27].
The complex template, which combines the soft template with the
hard template, or two hard templates, or two soft templates of different
length scales, has been used to prepare hierarchically bi-modal and tri-
modal porous structures with the primary objectives of minimizing
diffusion resistance and improving the accessibility of various surfaces.
For instance, bimodal mesoporous–macroporous materials with
interconnected pore channels can be prepared by using surfactant template
in combination with a colloidal-crystal template [17]. The surfactant template
can also be combined with polymer foam [18], bio-cellulose [19], emulsion
[20], inorganic salt [21], and ice crystal templates [22].
Fig.6 shows the schematic representation of the structure of a
new type of hierarchically three-length-scaled porous zirconium oxide
material with high BET surface area of > 900 m2 g
–1, having a uniform
macroporous (300–500 nm) structure of a supermicroporous (1.5 nm)
nanoparticle ( 25 nm in size) assembly with irregular mesovoids (20–60
nm) in the macroporous walls [34].
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Fig.6. Schematic representation of the structure of a new type of hierarchically three-length-scaled porous zirconium oxide material [34].
Nanocasting strategies are becoming more and more usual tool
for the preparation of novel porous materials, ranging from
nanomicroporous to nanomacroporous materials, and further to
hierarchically structured porous nanomaterials.
References
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Prezent si viitor, vol.1.,Casa Editoriala Demiurg, 2007. 2. F. Schüth, Chem. Mater., 2001, 13, 3184. 3. H. Yang and D. Zhao, J. Mater. Chem., 2005, 15, 1217. 4. Smarsly, S. Polarz and M. Antonietti, J. Phys. Chem. B, 2001,
105, 10473. 5. E. Krämer, S. Förster, C. Göltner and M. Antonietti, Langmuir,
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Brunet-Bruneau and A. R. Balkenende, Adv. Mater., 2001, 13, 1085. 9. K. K. W. Wong, S. Mann, Adv. Mater., 1996, 8, 928. 10. X. Liu, B. Tian, C. Yu, F. Gao, S. Xie, B. Tu, R. Che, L. M. Peng
and D. Zhao, Angew. Chem. Int. Ed., 2002, 41, 3876. 11. F. Kleitz, S. H. Choi and R. Ryoo, Chem. Commun., 2003, 2136. 12. Y. Sakamoto, T. W. Kim, R. Ryoo and O. Terasaki, Angew.
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15. P. Yang, D. Zhao, D. I. Margolese, B. F. Chmelka and G. D. Stucky, Nature, 1998, 396, 152.
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Angew. Chem., Int Ed., 1996, 35, 541. 11. 20. G. S. Attard, P. N. Bartlett, N. R. B. Coleman, J. M. Elliott, J. R.
Owen and J. H. Wang, Science, 1997, 278, 838. 21. G. S. Attard, C. G. Goltner, J. M. Corker, S. Henke and R. H.
Templer, Angew. Chem., Int. Ed. Engl., 1997, 36, 1315. 22. J. L. H. Chau and K. L. Yeung, Chem. Commun., 2002, 960. 23. R. Rockmann
and Grit Kalies, Applied Surface Science, 253,
2007, 5666. 24. E. Delahaye, V. Escax, N. El Hassan, and A. Davidson, J. Mater.
Chem., 2006, 16, 623.
25. T. Tsoncheva, J. Rosenholm, C.V. Teixeira, M. Dimitrov, M. Linden
and C.Minchev, Microporous Mesoporous Mater., 89, 1-3, 2006, 209.
25. B. Tian, X. Liu, B. Tu, C. Yu, J. Fan, L. Wang, S. Xie, G. D. Stucky and D. Zhao, Nat. Mater., 2003, 2, 159.
26. F. Schulth, Chem. Mater., 2001, 13, 3184. 27. Choi, M.; Heo, W.; Kleitz, F.; Ryoo, R. Chem. Commun. 2003,
1340. 28. F. Schuth, Chem. Mater., 2001, 13, 3184. 29. S. H. Joo, S. Jun and R. Ryoo, Microporous Mesoporous Mater.,
2001, 44, 153. 30. R. Ryoo, S. H. Joo and S. Jun, J. Phys. Chem. B., 1999, 103,
7743. 31. Valdes-Solis, A.B.Fuertes, Materials Research Bull. 41, 2006, 2187
32. F. O. M. Gaslain, J. Parmentier, V. P. Valtchev and J.l Patarin, Chem. Commun., 2006, 991.
33. A.Vinu, M. Miyahara, T. Mori, K.Ariga, J Porous. Mater.,2006, 13: 379.
34. A. Vantomme, Z.Y. Yuan and B.L. Su, New J. Chem., 2004,28, 1083.
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PL.9. Nanomaterials for Environmental Applications
N.Bilba “Al.I.Cuza” University of Iasi, Faculty of Chemistry
Environmental pollution and destruction on a global scale, as well
as the lack of sufficient clean and natural energy sources have drawn
much attention and concern to the vital need for ecologically clean
chemical technology, materials and processes.
The increasing ability of scientists to manipulate the matter
virtually atom by atom, to create and use structures, devices and systems
that have unique physical an chemical properties and functions because
of their small size in a nanometer scale can be expected to have a
significant impact on sustainable development and an enormous potential
for industry and technology, social, economic and environmental benefits.
Materials with very small features (particle size or grain size) on
the order of 1-100 nm of at least one dimension are known as
nanomaterials.
The reason the scientific community has such an interest objects
operating at such a small length scale are because, at lengths under ∼
100 nm, materials stop exhibiting bulk, macroscopic characteristics and
start exhibiting unique nanoscopic characteristics.
Two principal factors cause the properties of nanomaterials to
differ significantly from other materials:
- increased relative surface area,
- quantum effects.
These factors can change or enhance properties such as
reactivity, strength, optical, electrical and magnetic characteristics.
As a particle decreases in size, a greater proportion of atoms are
found at the surface compared to those inside (for example, a particle of
size 30 nm has 5% of its atoms on its surface, at 10 nm has 20% and at 3
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Environmental (clean water, air
and soil)
- Healt care (tissue and bone
repairs, drug delivery)
- cosmetics
Clean energy (GTL, H2, Coal,
natural gas, fuel cells, Li-ion
battery, green
nm has 50% of its atoms on its surface). As catalytic chemical reactions
occur at surfaces, this means that a given mass of material in
nanoparticulate form well be much more reactive than the same mass of
bulk material.
Ultrafine microstructures produced by the consolidation or the
assembly of building blocks having an average phase or grain size range
from ∼ 1 (molecular scale) to ∼ 50 nm are classified as nanostructured
materials.
Nanomaterials can be metals & alloys nanoparticles, ceramic
nanoparticles, nanoporous materials, nanopolymes, nanocomposite
materials, carbon based nanomaterials and biological nanomaterials.
Nanostructured materials include: atomic clusters, layered
(lamellar) films, filamentary structures, nanocrystalline materials,
nanocomposites and bulk nanostructured materials.
Areas of nanomaterials applications:
Most environmental applications of nanomaterials and of
nanotechnologies fall into four categories:
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1. Environmental remediation to clean up past environmental
damage:
- nanomaterials and nanotechnologies for water remediation:
nanoporous membranes, nanofibres, nanoparticles,
nanofiltration, sorption, ion exchange;
- nanomaterials and nanotechnologies for air remediation
(POP-s, VOC-s, HAP-s):
nanofibers, nanoporous membranes, adsorbents;
2. Environmental protection to correct present environmental
problems:
- transportation: nanocatalysts;
- pesticide replacements;
- nanotechnologies for recycling.
3. Environmental maintenance to prevent future environmental
impacts:
- nanosensors for air quality;
- nanosensors for water quality;
- nanosensors for radiations.
4. Environmental enhancement to sustain the planet for future
generation:
- green technologies (manufacturing);
- food processing enhancement (package materials, storage
life sensors, additives).
With respect to remediation of environmental contaminants, the
applied nanotechnologies can be adsorptive versus reactive and in situ
versus ex situ.
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PL - 9. Coronands with Multiple Binding Sites
Ionel I. Mangalagiu*, Ana Maria Balan, Ondina Florea “Al. I. Cuza” University of Iasi, Organic and Biochemistry Department, Bd. Carol 11, 700506 Iasi, Romania. e-mail: [email protected]
During the last decades host-guest chemistry has emerged as a
central paradigm within organic chemistry.
The emphasis of this work was to design and to synthesize a new
class of coronands possessing multiple binding sites. This class are
coronands with oniu skeleton and contain two main units: a
dihydroxyacetophenone unit (with aliphatic or aromatic arms) and a
nitrogen heterocycle one (Schema 1, compound III); the obtaining
pathway could be rationalized bellow:
Acknowledgements: to Romanian Ministry of Research and
Education - MATNANTECH program, grant no. 36/2005, for financial
support.
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O - 1. NANOSTRUCTURED POROUS MATERIALS
O-1-01. The Influence of Hydrolysis Parameters on the Synthesis of Zr, Y and Al Nanocrystalline Compounds
Laura M. Popescu*, Cristina F. Rusti, Adrian M. Motoc, Roxana M. Piticescu, Radu R. Piticescu National R&D Institute for Non-Ferrous and Rare Metals, Pantelimon, Ilfov, RO, *[email protected], [email protected]
Nanomaterials have been studied since the 1990s because of
their specific features. Nowadays, an increasing attention is paid to the
environmental friendly obtaining methods of nanomaterials that could
control the grain size and which are easy to implement at the small and
medium enterprises (SMEs) level. High pressure hydrothermal synthesis
in aqueous solution follows the trend of these new techniques.
In the present paper hydrolysis reactions for the synthesis of ceramic
powders based on Y doped ZrO2 and ZrO2-Al2O3 were investigated. The
preliminary studies revealed the application potential of these
nanomaterials in the field of nanomedicine, sensors, FGMs, high added
value materials. The main objective was the study of precipitation-
dissolving equilibriums of Zr, Y and Al salts which take place in precursor
suspension of metallic oxides in order to obtain powders with small
crystallite sizes. Precursor suspension is introduced in the autoclave
under high pressure. The different solubility of the precipitating species
influences the kinetics of the co-precipitation reaction. This can determine
the formation of heterogeneous precipitate. Solubility and conductivity
measurements of the reaction system were performed to establish the
optimum working conditions (pH, temperature) that will determine the
formation of fine, small sized crystallites.
Hydrolysis degree, q, which determines the hydrated species
composition, can be estimated taking into account the Sanderson
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hypothesis which states that in a chemical compound the participant
atoms tend to equal their electronegativities. Hydrolysis degree increases
with increasing cation valence and electronegativity. Zr hydrolysis degree
is greater than that of Al. Hence, Zr4+
ions precipitate before Al3+
ions at
more acid pH value. Aqueous solutions of zirconium salts showed a
strong hydrolysis tendency due to their great electric charge and small
ionic radius.
Unlike Y doped ZrO2 system where Y and Zr cations have
comparable ionic radii and only one equivalence point is observed, ZrO2-
Al2O3 system showed two equivalence points corresponding to totally
different precipitation pH of Zr4+
and Al3+
.
Based on these preliminary results, further studies are necessary to
elaborate methods that investigate the in situ behaviour of the same
systems under high pressure conditions.
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O-1-02. Characterization of Nanostructured Ni-Al-M (M: Co, Fe) Composites Prepared by TVA Method
A. M. Lungu1, C. P. Lungu1, I. Mustata1, A. Anghel1, C. C. Surdu-Bob, P. Chiru1, O. Pompilian1, E. Dutu1, M. Badulescu1, V. Zaroschi1, C. Iacob1, C. Georgescu1, R. M. Piticescu2, R. Piticescu2, S. Stoleriu3, V. Ciupina4, R. Vladoiu4, G.Prodan4 1 National Institute for Laser, Plasma and Radiation Physics,
Bucharest, Romania [email protected] 2 National R&D Institute for Non-Ferrous and Rare Metals
Bucharest, Romania 3 ”Politehnica” University, Faculty of Applied Chemistry and
Material Science, Bucharest, Romania 4 “Ovidius” University, Constanta, Romania
Ni-Al-M (M: Co, Fe) nanostructured composite films were
prepared using the original thermionic vacuum arc (TVA) method
developed at NILPRP [1]. The method uses three separate electron
beams emitted by three externally heated cathodes (grounded tungsten
filaments) accelerated by three high anodic voltages. The electron beams
evaporate the metals used as anodes as neutral metal atoms. Applying
high voltages (1-5kV) between cathodes and respective anodes, bright
plasmas in pure metal atoms were ignited simultaneously. The plasmas
were controlled independently by the electron beams (thermoelectrons)
emitted by the heated cathodes. The process parameters (discharge
current and plasma potential) were studied and optimized.
The Ni-Al-M films were characterized by transmission electron
microscopy (TEM) as inter-metallic complex of nanocrystals of 5-10 nm
average diameters. The prepared samples were characterized also by
scanning electron microscopy (SEM), electron dispersive spectrometry
(EDS), X-ray diffraction (XRD), atomic force microscopy (AFM), gravimetric
thermal analysis (GTA) and differential thermal analysis (DTA).
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References
1. C. P. Lungu, I. Mustata, G. Musa, A. M. Lungu, V. Zaroschi, K. Iwasaki, R. Tanaka, Y. Matsumura, I. Iwanaga, H. Tanaka, T. Oi, K. Fujita: Surf and Coat. Techn, Vol.200, 399-402,2005
O-1-03. Optical Characterization of Cu/Ni/NiOx Thin Films Used as Selective Surfaces for Flat Plate Collectors
Mihaela Voinea*, Cristina Bogatu, Anca Duta* *The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 e-mail: [email protected] Economical and efficient conversion of the solar radiation
into thermal energy requires a low cost spectrally selective solar absorbing surface. These coatings must present a large absorption coefficient and a small reflection coefficient in the spectral range of the solar radiation corresponding to the photon energies E > 0.5 eV, and low emission or high reflection in the IR spectral range at E < 0.5 eV. Black nickel layers Ni/NiOx can be used as selective surfaces due to their good optical properties.
Thin films of NiOx were deposited by spray pyrolysis deposition
technique (SPD) onto a copper substrate previously coated with
electrolytic nickel. Aqueous solutions of nickel chloride were used as
precursors for SPD. The deposition parameters (precursor’s concentration
and temperature) were varied in order to optimize the films properties.
The optical properties of the films (UV-VIS, IR) were correlated with their
chemical composition, crystalline structure (XRD) and morphology (AFM).
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O - 2. ADVANCED MULTIFUNCTIONAL MATERIALS O-2-01. Multifunctional Bio and Chemical Sensors Based on
Wide Band Gap Materials
Anita Lloyd Spetz, Kristina Buchholt, Rodrigo Petoral, Kajsa Uvdal Per-Olov Käll, Doina Lutic*, Mehri Sanati**, Rositza Yakimova.
Div of Applied Physics, Dep. of Physics, Chemistry and Biology, Linköping University, SE-581 83 LINKÖPING, Sweden
* Al. I. Cuza University of Iasi, Faculty of Chemistry, Bd. Carol I 11, 700506 IASI, Romania
** Dep. of Technology and Design, Växjö University, SE-351 95 VÄXJÖ, Sweden [email protected]
The multifunctional properties of wide band gap, WBG, materials
like SiC, GaN/ GaAlN, AlN, ZnO and Diamond provide the possibility of
multifunctional bio and chemical sensors. Semiconducting and
piezoelectric properties introduce parameters like resistivity, potential,
mass changes and temperature to be measured. Excellent properties like
high melting point, chemical inertness and biocompatibility enable
applications such as in car exhausts, flue gases, oil wells or in the
stomach. For example SiC devices have been operated up to 1000°C.
Using the piezoelectric properties of AlN, resonator devices have been
processed with a frequency of 2 GHz and thereby potentially extremely
high sensitivity. The ZnO material exhibit potential as multisensing
material, since both FET and resonating devices are realized. The
material is a semiconducting oxide, which makes it especially interesting
for bio and chemical sensors. The oxide surface provides both oxygen
sites for the gas response in a FET device and also sites for
functionalization by biomolecules. We have successfully functionalised the
ZnO surface by APTES and MPTMS [1]. Also the SiC surface was
successfully functionalised. Here it was of special interest to investigate
the insulating properties of the biomolecule layer [2]. Also, the use of
nanoparticles as the sensing layers in FET chemical sensor devices has
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been explored. Au nanoparticles show an increased response to NO or
NO2. Pd showed an interesting fractal particle formation and also
increased sensitivity to NO. For devices based on SiC/ZnO, thin film of
ZnO was compared to ZnO nanoparticles and it was shown that the
oxygen sensitivity increased for nanoparticles.
References
1. R. M. Petoral Jr., G. R. Yazdi, A. Lloyd-Spetz, R. Yakimova, K.
Uvdal , Organosilane-functionalized wide bandgap semiconductor surfaces, Appl. Phys. Lett. In press
2. R. Yakimova, R.M.Petoral Jr., G.R. Yazdi, C. Vahlberg, A.Lloyd
Spetz and K. Uvdal Surface functionalization and biomedical applications based on SiC, J. Phys. D., in press
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O – 2-02. Advanced Multifunctional Materials from Maleic Anhydride Copolymers
Gabrielle Charlotte Chitanu, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania; e-mail: [email protected]
Maleic anhydride copolymers are particularly suitable for
preparation of multi-functional materials. Their chemical structure can be
tailored either by the appropriate choice of the comonomer (hydrophilic or
hydrophobic) or by chemical reaction with suitable low molecular
compounds bearing different functions: charged groups (which cause
them to behave as polyelectrolytes), dyes or chromophores, bioactive
molecules, LC moieties, and other. Moreover they can be obtained from
easily accessible commercial monomers which are relatively cheap, by
convenient radical copolymerization in organic solvents using common
initiators. The co-monomer can be N-vinylpyrrolidone (NVP), vinyl acetate
(VA), methyl methacrylate (MMA), or styrene (St), given in the order of
increasing hydrophobic character.
In this paper will be presented recent results regarding new materials
based on maleic anhydride copolymers:
• layer-by-layer deposition from maleic polyelectrolytes and
different cationic low or high molecular partners;
• supramolecular systems in which one of the partners are
maleic anhydride/acid copolymers. Original results are presented
regarding the interaction of maleic acid copolymers with collagen
hydrolysate or the intermacromolecular complexes formed between
maleic acid copolymers and chitosan.
Acknowledgement: The financial support of Romanian
National Authority for Scientific Research, CEEX projects no. 42/2005
(RO-NANOMED) and 14/2005 (NANOAGMAM), is gratefully
acknowledged. We are thankful for the collaboration with Dr. Gabriela
Aldea and Prof. Jean-Michel Nunzi, University of Angers, France, and
Prof. Heikki Tenhu and Dr. Adina Graziella Anghelescu-Dogaru,
University of Helsinki, Finland.
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O – 2-03. The Use of Oxide-Type Solids in Chemical Sensor
Formulations
Doina Lutic, Mehri Sanati*, Anita Lloyd-Spetz** “ Al. I. Cuza” University of Iasi, Faculty of Chemistry, 11 Bd. Carol
I, 700506 Iasi, Romania, [email protected], [email protected] * Dep. of Technology and Design, Växjö University, SE-351 95
VÄXJÖ, Sweden ** Div of Applied Physics, Dep. of Physics, Chemistry and Biology,
Linköping University, SE-581 83 LINKÖPING, Sweden
The sensitive layer in a chemical sensor is for example a solid
able to catch the sensed molecules by physical adsorption or by
chemisorption; this is often followed by chemical reactions like
combustion. During this interaction, some properties of the sensitive layer
will change (density of charge carriers, colour, light emission, mass, etc.).
The oxides, characterized by selective uptake for different classes of
molecules from mixtures, are widely used for sensor formulations.
Beside the widely used SnO2 as main compound in resistor-based
sensors, several other oxides as: titania, chromia, silica, alumina, ITO
(indium-tin oxide), rare-earth oxides and even zeolites and mesoporous
materials are reported in the literature. The detection mechanism
comprises mostly resistance changes, but also impedance
measurements, surface polarization (field effect sensors), mass changes
(QMB sensors), light emission (cataluminescence sensors), optical
sensors etc.
The conference will review some recent interesting results from
literature comprising sensors based on nanocrystalline oxides,
microporous oxides (zeolites and aluminophosphates) and mesoporous
oxides.
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References
1. D. Lutic, M. Sanati and A. Lloyd Spetz, “Gas Sensors”: in
“Synthesis, Properties and Applications of Oxide Nanomaterials”, Wiley-Interscicence, J. A. Rodriguez and M. Fernandez-Garcia (editors), 2007, p. 411.
2. X. Xu, J. Wang and Y. Long, “Zeolite-based Materials for Gas Sensors (review)”, Sensors, 6, 2006, p. 1751.
3. G.E.Fryxell, “The synthesis of functional mesoporous materials (mini review)”, Inorganic Chemistry Communications, 9, 2006, p.1141.
4. H. Fan, S. Reed, T. Baer, R. Schunk, G.. Lopez and C.J. Brinker, “Hierarchically structured functional porous silica composite produced by evaporation-induced self assembly”, Microporous and Mesoporous Materials, 44-45, 2001, p. 625.
5. D. Lutic, M. Strand, A. Lloyd-Spetz, K. Buchholt, E. Ieva, P.-O. Käll and M. Sanati, “Catalytic properties of oxide nanoparticles applied in gas sensors”, accepted, “Topics in Catalysis”
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O – 2-04. Magnetic Nanostructures grown in Porous Polymer Structures
N Sulitanu, F. Brinza, V. Tura Solid State and Theoretical Physics Dept., Faculty of Physics, Al.I.Cuza University, 700506 Iasi, Romania
The new concept of magnetic nanoparticles, nanoclusters or
nanowires embedded in matrices of porous polymers are good examples
of functional nanostructures with excellent potential for applications such
as electromagnetic interference shielding, magneto-optical storage,
biomedical sensing, flexible electronics, etc. Possibly, polymer coated
nanostructures are the only starting material to produce macroscopic
parts showing the very special properties of nanomaterials. The very
special properties of nanomaterials often are properties of isolated
particles. By proper selection of the porous polymer it is possible to avoid
grain growth and to properly change of the strength of magnetic
interaction. Therefore, to obtain macroscopic parts exhibiting the
properties of the isolated particles it is necessary to avoid or at least
reduce the interaction of the particles. This can be achieved by coating
each individual particle with a polymer layer or by polymer filling with
nanoparticles. Control over the dispersion of the nanoparticle phase
embedded in a polymer matrix is critical and often challenging. To achieve
excellent dispersion, competition between polymer-polymer and polymer-
particle interactions have to be balanced to avoid clustering of particles in
polymer nanocomposites. This type of materials can be synthesized by a
variety of methods such is: electrodeposition, CVD, chemical co-
precipitation from solution, microwave plasma polymerization, spin-
coating etc.
Moreover, we present here our results upon various magnetic
nanoclusters grown in polyethylenetereftalate, nanoporous nanofibrous
polyurethane, nanofibrous polyvinylchloride and nanoporous polyethylene
membranes. X-ray diffraction-XRD, cross-sectional scanning electron
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microscopy-SEM, transmission electron microscopy-TEM, and magnetic
measurements confirm the excellent dispersion and magnetic response of
nanoclusters embedded in porous polymers.
References
1. F. Johnson, C.Y. , Um, M.E., McHenry, H. , Garmestani, JMMM
Volume 297, issue 2, February 2006, 93-98. 2. N. Sulitanu, F. Brinza, Romanian Patent (Part of Porous membrane
obtaining technology). 3. N. Sulitanu, F. Brinza, Engineering Functional 1D Magnetic
Nanostructures by Electrodeposition, Bul. Inst. Polit. Iasi, Tomul LII (LVI), Fasc.:1-2, Sect.: Math.,Mech. & Phys., 127 (2006).
Fig. 1. Cross-sectional SEM view of
porous polyurethane with magnetic nanoclusters
Fig. 2. Cross-sectional view of porous
PE coated FeCo nanoclusters.
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O-3. NATURAL AND SYNTHETIC ZEOLITES
O – 3-01. Attenuation β-Ray Study through Materials on the Basis of Natural Zeolites
Bogdan-Ion Mocanu*, Nicolae Naum**, Ion Gruia*** * Refinery Petrobrazi, Brazi, Prahova district,
[email protected] ** Management Programs National Centre from Education and
Research Ministry, No.21-25 Mendeleev street, Bucharest, [email protected]
*** University Bucharest, Physics Faculty, Magurele, [email protected]
In this paper, it was studied β-ray attenuation through the material
type of “roman concrete”, having in the composition natural zeolites
(clinoptilolite), which carried out before an ionic exchange with strontium.
Purpose of this work was to prove safety stocking possibility with
very low costs, of a mineral ion-exchangers (zeolitic volcanic tuffs),
saturated by ionic exchange with Sr-90, β activity radionuclide.
In the end of this paper, it proposed for safety radioprotection
stocking of the solid residues resulted from the ionic exchange, a efficient
and especially cheap method, by the obtaining concrete by pozzolanic
reaction (due to high reactionable silica content), followed by the stocking
in the abandoned mines (this sort of binder having an enhanced
resistance at the corrosion, which could exceed resistance of the
concretes obtained from the Portland cement).
Key-word: roman concrete, clinoptilolite, strontium, pozzolanic reaction.
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O – 3-02.The Improvement of Retention Capacity of ETS-10 towards Uranyl Ions by Porosity Modification
Claudiu C. Pavel, Karin Popa “Al.I. Cuza” University, Department of Inorganic and Analytical Chemistry, 11-Carol I Blvd., 700506 - Iasi, Romania, e-mail: [email protected]
ETS-10 is a microporous titanosilicate with a unique structure of
linked SiO4 tetrahedra and TiO6 octahedra that attracts interest for shape-
selective photocatalysis, optoelectronics, and selective gas adsorption.
Apart of its catalytic properties, it was found to be a very effective material
in purification of (nuclear) waste waters. In a previous study [1] we have
shown that the radioactive form of some small cations like Co2+
, Cd2+
, and
Hg2+
can be sequestrated by this material up to its ionic exchange
capacity (about 4.5 meq/g). Contrarily, the uptake of UO22+
ions was found
to be much lower [2], perhaps because of the very high ionic radius of the
hydrated uranyl ions. Also the uranium uptake seems to be dramatically
influenced by the synthesis procedure of ETS-10 [2].
Recently, the porosity of ETS-10 was modified by introduction of
supermicropores (essentially as coalescence of neighboring micropores) and
mesoporosity via post-synthesis treatments with hydrogen peroxide [3,4].
A qualitative study of the diffusion properties of ETS-10 as a
function of its porosity has been performed by adsorption of rhodamine
6G. The main results which were found out are: (i) initial time adsorption
kinetics is determined by super- and mesoporosity, (ii) the amount of
adsorbed molecule is proportional to the quantity of introduced porosity,
and (iii) long time adsorption kinetics is determined by microporosity and
can modified by the presence of supermicropores.
This preliminary study has encouraged us to use the modified ETS-10 in
retention of the large uranyl ions from aqueous solution using batch-type
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method. The mesopores-containing ETS-10 samples show a much higher
uptake of uranyl ions compared to the as-made material at different
temperatures. Our results are very satisfactory and the distribution
coefficient (Kd) was double than the one found by Al-Atar et al. [2], as a
function of the experimental temperature and the contact time. It seems
that the increased porosity permits a better contact in the uptake system,
since the diameter of the pores is much higher than the ionic radius of the
hydrated uranyl ion. This hypothesis has to be validated, EXAFS
experiments being ongoing at the present time.
A kinetic and thermodynamic evaluation of the uptake data was
performed and the standard thermodynamic parameters were calculated.
References
1. C.C. Pavel, K. Popa, N. Bilba, A. Cecal, D. Cozma, A. Pui,
J. Radioanal. Nucl. Chem., 258(2) (2003) 243-248. 2. L. Al-Atar, A. Dyer, R. Blackburn, J. Radioanal. Nucl. Chem.,
246(2) (2000) 243-248. 3. C.C. Pavel, So-Hyun Park, A. Dreier, B. Tesche, W. Schmidt,
Chem. Mater., 18(16) (2006) 3813-3820. 4. C.C. Pavel, W. Schmidt, Chem. Commun., (2006) 882-884.
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O – 3-03. Synthesis and Characterisation of Molecular Sieves Titanium and Phosphorus Based for Water Depuration
D. Vuono*, N. A. Turta, P. De Luca*, A. Nastro* * Department of Pianificazione Territoriale, University of Calabria, via P. Bucci, I-87036 Arcavacata di Rende (CS), Italy. e-mail: [email protected] “Al.I.Cuza” University of Iasi, Faculty of Chemistry, Laboratory of Materials Chemistry, Carol I Bvd. No. 11, 700506 Iasi, Romania.
The aim of this research is to synthesise ET(P)S-4 and ET(P)S-10
determining their exchange capacity, variation of crystalline framework
and thermal stability. The study of ion exchange properties of those
materials is useful to determine their own possible application in water
depuration from urban and industrial water wastes. The analyses to
determine chemical composition of molecular sieves are carried out
before and after ion exchanges. The ET(P)S-4 and ET(P)S-10 are
synthesised from two solutions: acidic and basic solutions. In acidic
solution is added P2O5. The synthesis procedure is described in studies of
Pavel et al. [1]. The ion exchange is carried out using Na+, K
+, Li
+, Mg
++
and Ca++
ions. 2.5 gr of ET(P)S (4 or 10) are added to 250 ml of a 1 M
solution of clorures of several cations (NaCl, KCl, MgCl2, CaCl2, LiCl). The
solutions are omogenised for 2 minutes. The ion exchange are carried out
for 24 hours at room temperature. The solutions are regenerated for 3
times to stabilise the exchange conditions during 96 hours of test. The
microporous materials are filtered and dried at ca. 100°C. The so-obtained
powders are characterised by thermogravimetric analysis, XRD analysis
and chemical and morphologic analyses. After the characterisation, the
two molecular sieves present good ion exchange properties. It is noted
ET(P)S-4 has the best exchange capacity (4.7 meq/gr). The monovalent
cations present a best trend to be exchanged than the bivalent cations.
The exchange for both zeotypes is never complete except for Na-ET(P)S-
4 totally becoming sodic. Thermal stability of both sieves was carried out
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for all exchanged cations. The ET(P)S-4 shows a high stability after the
ion exchange with potassium. The ET(P)S-10 presents a high stability
after exchange with calcium. The morphologic studies before and after ion
exchanges do not present changes.
References
1. P. A. Sandomirskii, N. V. Belov, Sov. Phys. Crystallogr., 24, 686-
693, 1979.
2. A. Philippou, M.W. Anderson, Zeolites, 16, 98-107, 1996.
3. C.C. Pavel, D. Vuono, L. Catanzaro, P. De Luca, N. Bilba, A.
Nastro, J.B. Nagy, Microporous and Mesoporous Materials 56,
227–239, 2002.
4. D. Vuono, C. C. Pavel, P. De Luca, J. B. Nagy and A. Nastro,
Journal of Thermal Analysis and Calorimetry, 80, 585–590, 2005.
5. C.C. Pavel, D. Vuono, P. De Luca, N. Bilba, J. B.Nagy, A. Nastro,
Microporous and Mesoporous Materials 80, 263–268, 2005.
6. G. Cruciali, P. de Luca, A. Nastro, P. Pattison, Microporous and
Mesoporous Materials, 21, 143-153, 1998.
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O-5. CATIONIC AND ANIONIC CLAYS
O - 5-01. In Vitro and in Vivo Behavior of Ketoprofen Intercalated in Zn Al Layered Double Hydroxides
Ionel Marcel Popa1, Costin Mungiu2, Mihaela Frunza1, Georgeta Ionescu Dunarea2, Irina Jaba2, Bogdan Tamba2, 1 Technical University, Iasi, Romania, 2 University Medicine and Pharmacy “Gr.T. Popa” Iasi,
Romania; [email protected]
Layered double hydroxides (LDH) are amongst attractive
materials for the preparation of a controlled release formulation [1, 2]. The
large variety of anions that can be incorporated in the layered double
hydroxides and the high anionic exchange capacity of these materials
allow us to use them as matrices for tailoring specific organic–inorganic
hybrid nanostructures with new potential applications such as: designing
new pharmaceutics and new biocompatible materials [3, 4].
In the present study, we report the formation of a layered
nanohybrid material by intercalation of ketoprofen (KET) into the ZnAl
layered double hydroxides (ZnAlLDH) for controlled release formulation
purposes. The release of ketoprofen from the interlamella of an organic-
inorganic nanohybrid material could by controlled by adjusting the type
and the concentration of the anion in the release medium, the pH of the
release medium. The rate of drug diffusing out of the matrix is controlled
by the rigidity of the layers and the diffusion path length. These results
demonstrate that intercalation of KET in the interlayer of hydrotalcite
reduces gastric damage.
References
1. S. Y. Kwak, W. M. Kriven, M. A. Wallig, J. H. Choy, Biomaterials
25 (2004) 5995- 6001.
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2. M. Frunza, G. Carja, M. I. Popa, Scientific Study & Research, VI 2, (2005), 173-180.
3. B. Li, D. Evans, X. Duan, Appl. Clay Sci. 27, (2005), 199-207.
4. Z. Wang, E. Wang, L. Gao, L. Xu, J. Solid State Chem., 178, (2005), 736-741.
Acknowledgment: This work has been supported by Ministry of
Education and Research Romania, by CEEX 108/2006.
O – 5-02. Zn/Al Layered Double Hydroxides: Synthesis and
Photocatalytic Application
E. M. Seftela,b, E. Popovicia, P. Coolb, E. F. Vansantb
a “Al. I. Cuza” University of Iasi, Department of Physical and Theoretical Chemistry and Materials Chemistry, Bvd. Carol I, 11, 700506, Romania, e-mail: [email protected]
b Laboratory of Adsorption and Catalysis, Department of Chemistry, University of Antwerpen (CDE), Universiteitsplein 1, 2610 Wiljik, Antwerpen, Belgium
Introduction. Layered Double Hydroxides have the general formula [MII1-
xMIII
x(OH)2]x+
·(An-
x/n)·mH2O, where MII and M
III are the divalent and trivalent
cations and An-
the anions that maintain the electro-neutrality of the
brucite-like sheets. The thermal stability of these materials is strongly
related with several factors, such as the nature of the cations and the
cationic ratio in the brucite-like sheets, the nature of the compensating
anions and the crystallinity degree of the LDH lattice [1].
Experimental. Zn/Al-LDHs with the cationic ratio of 1 to 4 were prepared
by the co-precipitation at low supersaturation method at constant pH
[2, 3]. Part of these samples was calcined at 300°C and 500°C in a Lenton
furnace. As a reference sample, ZnO was prepared following the same
method and calcined at 500°C. The photocatalytic activity was evaluated
for the degradation of methyl-orange dye under UV-illumination.
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Results and discussion. The XRD patterns revealed that for all the
cationic ratios the layered structure was formed. Additional ZnO phase is
present in all samples due to the longer hydrothermal treatment at 80°C.
Phase transformations during the calcination were fully investigated by
XRD, TG/TGA, UV-vis DR and Raman Spectroscopy, N2
adsorption/desorption, SEM and EDX methods. The EDX analysis
showed that the increase of the temperature leads to a diffusion of the
Zn2+
cations to the surface of the particles. The band gap energy
decrease as the temperature increase indicating that less energy is
needed for the photocatalytic process. Therefore, the photocatalytic
activity increases with the increase of the cationic ratio and the calcination
temperature.
Acknowledgments This study was supported by the NoE project
“Inside Pores” and the GOA project funded by the Special Fund for
Research of the University of Antwerp. This work is also part of the CEEX
No. 1/S/2005 project.
References
1. Auerbache S. M.,Corrado K. A., Dutta P. K., Handbook of layered
materials (2004) 373-449
2. Cavani F., Trifiro F., Vaccari A., Catalysis Today 11 (1991) 201-206.
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O-6. INDUSTRIAL AND ENVIRONMENTAL APPLICATIONS
O – 6-01. Research Concerning Achievement and Efficiency of some Multicomponent Retention Systems with Micro/Nanoparticles in Paper Industry
Constantin Stanciu “ Dunărea de Jos” University of Galaţi, Faculty of
Engineering Brăila, 29, Calea Calarasi, RO-810017, Romania; e-mail: [email protected]
The higher speed of paper machine, a lower pollution and higher
quality papers are three requirements for modern paper making:
These challenges can be accomplished by means of retention aids. The
most common synthetic retention aids are PEIs, PAAs and combinations
between these groups of products, and concerning natural products,
cationic starch and manogalactans (guam guar) can be mentioned. Of the
retention systems, multicomponent retention systems based on
micro/nanoparticles made of inorganic, anionic substances (bentonite,
colloidal silica etc ) and various cationic polymers (substitution degree
over 0.08%), PAAs and manogalactans can be mentioned.
The survey shows in its first part a number of theoretical elements
concerning the retention mechanisms as well as the influence factors
(type of microparticles, polymer charge density, influence of calcium
anions, paper stock pH, charge order of system components).
Experimental research aimed the achievement of some
multicomponent retention systems based on PAAs (low and medium
cationic charge), based on PAAEs and anionic colloidal silica. In order to
get some good results with such kind of systems, the charge for each
component should be set, the results varying depending on it.
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The optimum polymer charges were determined at a steady charge of
colloidal silica (0.01% in relation to o.d. material), physico-mechanical and
optical paper properties and waste water load were determined.
An important conclusion is that efficiency of micro/nanoparticles
diminishes with increasing the polymer charge. In order to set the
optimum charge of anionic colloidal silica, a steady charge of low cationic
charge polyacrylamide (0.03%) was used, the physico-mechanical and
optical paper properties and waste water load were determined.
It was noticed that maximum reduction of waste water suspensions
(below 50 mg/l) is recorded at an anionic colloidal silica charge of 0.9%.
To diversify micro/nanoparticle systems, a new retention system made of
a PAAE (61.6%), a commercial product (2%) and anionic colloidal silica
(0.9% and 0.8%) was surveyed and achieved.
The effect of charge order concerning system components
(polymer + colloidal silica or colloidal silica + polymer) was also studied
noticing that inverted system (micro/nanoparticles + polymer) leads to the
drop of strength and optical paper properties as well as to the high load of
waste water from paper machine.
Compared to other retention systems (single component, dual
polymer), the multicomponent systems with micro/nanoparticles have
obvious benefits as regards reduction of suspensions in waste water and
improvement of paper quality.
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O – 6-02. Comparative Study of Cr(VI) Removal from Aqueous Solutions Using Natural Sorbents and Purolite A 400 Resin
B. Robu, C. Balan, D. Bilba, I. Cretescu, M. Macoveanu
“ Gh. Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering and Management, 71 A D. Mangeron, 700050, Romania,
In this study the retention of chromium (VI) by sorption in batch
conditions onto Romanian sphagnum moss peat and respectively Purolite
A400 resin is discussed. The influence of experimental conditions for
Cr(VI) removal were studied tacking into consideration the initial
concentration of Cr(VI) and pH of solutions, adsorbent dose and
equilibration time. This investigation pointed out that the mechanism of
Cr(VI) removal from aqueous solutions using a sphagnum moss peat is a
complex process, involving both sorption and redox processes, while the
Purolite A400 resin presents a chemical stability, working mainly as ion
exchange material
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O - 7. OTHER ASPECTS OF NANOMATERIALS SCIENCE AND TECHNOLOGY
O – 7-01. Health Risks of Manufactured Nanomaterials
Cristina Rusti, Madalina Laura Popescu, Adrian Motoc, Roxana Piticescu, Stoiciu Maria National R&D Institute for Non-Ferrous and Rare Metals, Pantelimon, Ilfov, [email protected]
Nanotechnology is an emerging field of research and technology
dealing with the fabrication and engineering of materials, structures, and
systems with nano-scale size at least in one dimension. It is more of an
approach to engineering than a science, although it draws on the scientific
knowledge of biology, physics, chemistry, and materials science and is
expected to change these sciences dramatically. The applications of
nanotechnology range from next generation flat-panel TVs, advanced
solar panels, and chemical and biosensors to nanomedicine and energy
transmission efficiencies. When we talk about the health impact of
nanomaterials we need to differentiate 2 types of nanostructures: 1-
nanocomposites, nanostructured surfaces and nanocomponents
(electronic, optical sensor etc.) where nanoscale particles are
incorporated into a device, substance and material, also called „fixed”
nanoparticles;
2-„free” nanoparticles, where at some stage in production or use of
individual nanoparticles of a substance are present.
This paper is focused on environmental and health impact of
nanostructured materials obtained by hydrothermal synthesis. Some
advantages of hydrothermal method are listed bellow. Nanostructured
powders which cannot be prepared using other synthesis routes are easily
obtained starting from water soluble precursors, hydrothermal reaction
takes place in closed system (autoclave) and non-toxic products are set
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free in environmental medium during synthesis. Based on this aspect we
could say that this method is environmental friendly and is included in the
„fixed” segment of the nanomaterials. The systems obtained by
hydrothermal process are stable ones. Hydrothermal reactions are
influenced by some parameters namely: pH, time, pressure, concentration
of starting materials (soluble inorganic salts). With further analysis we can
determine the grain size and their structure. Depending on the starting
materials and synthesis parameters, NO3-, NH4
+, Cl
- and some other
cations could be present in mother solution and washing waters resulted
from filtering and washing of the precipitate. Their concentration was
controlled with chemical analysis (classical volumetry, gravimetry, spectral
methods such as ICP-inductively coupled plasma, colorimetry, atomic
absorption spectrometry) and is situated in the admitted range according
to national standards for waste waters.
Mapping the evolution of NO3-, NH4
+, Cl
- , and the presence of
nanomaterials in waste waters was performed for different hydrothermal
routes.
Further studies regarding the impact upon health and environment
will take place also because it is a quite new approach regarding
nanomaterials, and it is important to know how nanomaterials influence
our life.
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P-1. NANOSTRUCTURED POROUS MATERIALS
P-1-01. Electrical and Structural Properties of TiO2 Thin Films
Diana Mardare1, Nicoleta Cornei2, G.I.Rusu1 1 ''Al.I.Cuza'' University, Faculty of Physics, 11 Carol I Blvd., R-
700506, Iasi, ROMANIA, 2 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-
700506, Iasi, ROMANIA
Titanium oxide thin films have received worldwide attention and find
extensive applications in a lot of fields, due to its several advantageous
properties: high refractive index and permittivity, wide bandgap, chemical
stability, good transmittance of visible light, etc.
In this paper, titanium oxide thin films were obtained by a d.c.
sputtering technique. Depositing titanium oxide onto different substrates, at
different temperatures, and using O2 or H2O vapours as reactive gas, induces
structural changes. X-ray diffraction patterns show that the proportion of the
crystalline phases: anatase (tetragonal), rutile (tetragonal) and brookite
(orthorhombic) is the one that changes. A mixed anatase/rutile structure is
observed when deposited onto glass substrates, and only a rutile structure
when deposited onto silicon substrates, in the same deposition run. When
using O2 as reactive gas, both anatase and rutile phases are present for films
deposited onto glass and quartz substrates.
From the values of the lattice parameters, calculated using a refinement
CELREF program, it can be observed a slight dependence on the substrate
nature. The bond configuration of titanium oxide films, deposited onto silicon, was
obtained using FTIR in the wave number range: 400 cm-1 - 4000 cm
-1. The
features show the presence of Ti-O and Si -O bonds and also of small amounts
of water, except for the sample obtained with O2 as reactive gas.
As a consequence of the structural changes, the electrical
conductivities modify. The dependences of the electrical conductivity versus
inverse temperature were studied in a wide range of temperature (from 13 K
to 535 K). The activation energies have been determined, in each
temperature range.
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P-1-02. On The Synthesis and Characterization of Poly (Aspartic Acid)
Iordana Neamţu, Aurica P. Chiriac, Loredana Elena Nita, “Petru Poni” Institute of Macromolecular Chemistry Grigore Ghica Voda Alley no. 41A, 700487 Iasi, ROMANIA
Polyaspartic acid belongs to polyamine acids that are an important
class of synthetic polymers produced by chemical polymerization of the same
amino-acid building blocks found in naturally occurring proteins. Polyaspartic
acids (PAA) occur in nature as polypeptide sequences, i.e. in mollusk shells
or snails, regulating the calcium balance of these organisms.
Due in part to the carboxylate groups, polyaspartate has similar
properties to the polyacrylates. The polyaspartate polymers are analogues of
natural proteins, particularly the aspartate-rich proteins from oyster shells that
play a key role in regulating mineralization. Since the polyaspartate compounds
are derived from natural precursors, they are biodegradable and they can be
used to replace petroleum-derived polymers such as polyacrylate and
polyacrylamide. Because of their unique mineralization and ionic properties,
there exists an enormous range of possible applications for the polyaspartate
materials. In the medical domain it is possible its application as
superabsoebents (diapers), biomedical devices (for prevention of pathological
calcification, microencapsulation for drug delivery, surface coatings for implants
to promote crystallization), dental treatment (tartar control agents).
Currently, two principal chemical procedures are used to produce polyamine
acids. One approach links specifically amino-acid monomer units together by
amide bonds. At less complex chemical procedure, starting from
polysuccinimide that is produced by the polymerization of aspartic acid, and
then the polyimide rings are hydrolyzed with stoichiometric quantities of base
to form polyaspartate.
In the paper there are synthesized and comparatively characterized
the polymers from the viewpoint of zeta potential as a function of pH and
conductivity, with some considerations on the changes induced by the two
procedures and in direct connection with the final application as a biomaterial.
The rheological behaviour in dilute solution is also evidenced
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P-1-03. An EPR Investigation of the Core-Shell Effects in CMR Nanoparticles
C.Craciun, A.Popa(1), M.N.Grecu(2), Al.Darabont(1), D.Toloman(1), O.Raita(1), V.V.Grecu(3), M.Glinchuk(4), M.Fardis(5) , I.M.Giurgiu(1) Faculty of Physics, University “Babes-Bolyai”, Cluj-Napoca, Romania (1) National Institute for Research and Development of Isotopic and
Molecular Technologies, Cluj-Napoca, P.O.Box 700, Romania (2) National Institute for Materials Physics, 077125 Bucharest,
P.O.Box MG-7, Romania (3 )Faculty of Physics, University of Bucharest, 077125 Bucharest,
P.O.Box MG-11, Romania (4 )Institute for Problems of Materials Science, Kiev, Ukraine (5)
Institute of Materials Science, NCSR Demokritos, Athens, Greece, [email protected]
An EPR investigation in the paramagnetic regime of
La0.67Ca0.33MnO3-δ nanoparticles (radius ~ 45 nm) was carried out. In order
to obtain the core (∆c) and shell (∆s) line widths the experimental spectra
were fitted with the core – shell model. As resulting from our previous
investigations, the small – polaron hopping model could well describe the
line width temperature dependence for nanosized La0.67Ca0.33MnO3-δ
manganites [1]. Based on it, the analysis of the temperature dependence
of the core line width results in a value of ~ 89 meV for the polaron
activation energy in the core part of the nanoparticles.
We also discuss the theoretical EPR spectra of smaller nanoparticles
(radius < 45 nm) where the increased contribution of the shell component
causes an asymmetric distortion of the line shape.
References
1. L.M.Giurgiu, M.N.Grecu, Al.Darabont, O.Raita, X.Filip, O.Pana and
D.Toloman, Appl. Mag.Reson., 27, 139 (2004).
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P-1-04. Supramolecular Assemblies of Gold Nanoparticles
Mediated by Amino Acids and Aleurone Globular Protein
Aurora Mocanu,* Ossi Horovitz,* Emil Indrea,**Gheorghe Tomoaia,*** Ioan Bratu**, Maria Tomoaia-Cotisel* * ”Babes-Bolyai” University, Faculty of Chemistry and Chemical
Engineering, Physical Chemistry Department, Kogalniceanu Str., no. 1, 400028 Cluj-Napoca, [email protected]
** National Research and Development Institute of Isotopic and Molecular Technologies, P.O. Box 700, 400293 Cluj-Napoca
***”Iuliu Hatieganu” University of Medicine and Pharmacy, Department of Orthopedic Surgery, Traian Mosoiu Str., no. 47, 400132 Cluj-Napoca
Gold nanoparticles (size from 10 to 50 nm) were synthesized by
three different methods and were characterized by UV-Vis spectroscopy
and transmission electron microscopy (TEM). The shape and size
distribution of gold nanoparticles were determined. Gold nanoparticles
(GNP) were utilized both in colloidal solutions and as an nanostructured
gold film to investigate the interactions of GNP with various organic
compounds, such as amino acids (e.g., lysine, arginine, cysteine) and
aleurone globular protein. The gold films were prepared from gold
colloidal aqueous solutions on glass slides silanized with 3-aminopropyl-
triethoxysilane at room temperature and with a thermal treatment at high
temperature (e.g., 200oC). The globular protein is a major storage protein
extracted and purified from aleurone cells of barley. The binding
behaviour of organic molecules and GNP was studied using UV-Vis and
FTIR spectroscopy, scanning probe microscopy (e.g., AFM), transmission
electron microscopy (TEM) and X-ray diffractions.
By monitoring the evolution of the surface plasmon resonance
absorption of gold nanoparticles in colloidal solutions in the presence
of amino acids, the supramolecular assembly was shown to be
dependent on the amino acid structure and concentration, particularly
on their side groups such as thiol or amine group. These findings
provide new insights into the fabrication and physical characterization
of biomaterials made of gold nanoparticles and amino acids or globular
protein with potential applications in the nanoscience and
biotechnology.
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P-1-05. Multifunctional Assemblies of Gold Nanoparticles
Mediated by Aleurone Protein and Chitosan
Maria Tomoaia-Cotisel,* Gheorghe Mihailescu,** Liliana Olenic,** Gheorghe Tomoaia,*** Ioan Bratu,** Emil Indrea,** Irina Kacso,** Liviu Bobos,* Simina Dreve,** Aurora Mocanu*, Ossi Horovitz*
* Babes-Bolyai” University, Faculty of Chemistry and Chemi-cal Engineering, Physical Chemistry Department, Kogalni-ceanu Str., no. 1, 400028 Cluj-Napoca, [email protected]
** National Research and Development Institute of Isotopic and Molecular Technologies, P.O. Box 700, 400293 Cluj-Napoca
***”Iuliu Hatieganu” University of Medicine and Pharmacy, Department of Orthopedic Surgery, Traian Mosoiu Str., no. 47, 400132 Cluj-Napoca
We report an investigation of the aleurone protein interaction with
GNP in colloidal solutions and in gold nanostructured films. The results
indicated a remarkable effect of protein binding on GNP in colloidal
solutions and especially on the gold nanostructured films, where a
stronger interaction was evidenced than with gold colloids. The results
indicate that aleurone protein provides a versatile mediator for assembling
GNP into organized composite in the absence and in the presence of
chitosan directing to materials with varied functional response. The self-
assembly process provides nanocomposites with controlled interparticle
(clusters) spacings as determined by X-ray scattering, TEM and AFM and
modular optical behavior, as examined through UV-Vis spectra.
The cyclic voltammetry is used to study the electrochemical
behavior of multifunctional composite made of GNP, chitosan and
protein, and deposited on gold electrode. From cyclic voltammograms,
it is clearly evidenced that protein molecules near the gold electrode
surface are electroactive. Therefore, direct electron transfer between
the adsorbed protein and the electrode is achieved. This can lead to
the application of aleurone protein to direct electron communication in
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bioelectronic devices and biosensors using compozite materials based
on protein, GNP and chitosan. The compozite material is
multifunctional and offers a matrix where the protein is immobilized.
The three-dimensional, compozite material was deposited on gold
electrode and it appears that the protein has its role of a linker and of a
direct electron communicater.
These data provide new insights into the control of interfacial
interactions in the fabrication and chemical and physical characterization
of multifunctional materials made of gold nanoparticles, globular protein
and chitosan with potential significant applications (sensing material) in
the development of optical, electronic and analytical devices.
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P-1-06. Polysiloxanes Reinforced by in situ Precipited Silica Processed as Thin Films
Maria Cazacu, Mihaela Alexandru, Felicia Iacomi 1” P. Poni” Institute of Macromolecular Chemistry Iasi, Romania
2 “Al.I.Cuza” University, Faculty of Physics, Iasi. Romania
Cross linked polydimethylsiloxanes in situ reinforced with silica
have been prepared and processed as thin films by spin coating or thick
films by casting.
The procedure occurred in the absence of a solvent. The
prepared composites having different content of silica were investigated
by different techniques: XRD, IR, AFM. The structure and the surface
morphology are dependent in great measure on the composition.
Comparative studies were made on polydimethylsiloxanes
reinforced with ex situ silica. References
1. Z. Li, W. Han, D. Kozodaev, J. C. M. Broken-Zijp, G. de With, P. C. Thűne, Polymer 47, 1150-1158, 2006
2. Cazacu, M., Marcu, M., Macromol. Rep. A 32(7), 1019-1029, 1995 3. R. Saito, J. Polym. Sci.: Part A: Polym. Chem. 44, 5174-5181, 2006
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P- 1-07. Effects of Surfactant Adsorption on Nanomagnetic Particles Studied by Structural Methods
M.Balasoiu1,3, M.L.Craus2,3, A.I.Beskrovnyj3, D.Bica4, L.Vekas4. M.Lozovan2
1 Horia Hulubei National Institute for Physics and Nuclear Engineering Bucharest, Romania
2 National Institute of Research and Development for Technical Physics, Iasi, Romania
3 Joint Institute of Nuclear Research, Dubna, Russia
4 Romanian Academy- Section of Timisoara, Timisoara, Romania; [email protected]
The properties of nanostructured magnetic materials and
devices are extraordinarily different from those of conventional
magnetic systems. The very interest in the study of nanostructured
magnetic materials is related to the basic notion that novel effects and
properties may be expected whenever “crossing length scales”
appear in a system [1,2]. The synthesis and characterization of
nanomagnetic materials are essential to the future top applications
like these of data storage and biotechnology/medicine. To active
investigations are subjected a class of such magnetic nanostructured
systems the ferrofluids.
The ferrofluids represent colloidal suspensions of single domain
ferromagnetic particles of about 100A in diameter, stabilized with
surfactant molecules, in a suitable liquid carrier. From a considerable
number of experimental results (for example, EM analysis and
magnetic measurements) Comparing the particle size distribution
obtained from magnetic measurements it was concluded that the
physical and magnetic dimensions of the nanomagnetic particle are
different. This might be caused by magnetite surfactant interactions.
In latest publications such a behavior is considered to be due to an
intrinsic property of nonstructured magnetic materials.
The purpose of presented work is to investigate the influence of the
absorbed surfactant layer on the magnetic structure of the particles by
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structural methods (XRD, neutron diffraction, SANS). Conventional -2
X-ray diffraction scans using CoK radiation were recorded in order to
identify the crystallographic phases and to determine the average
coherent sizes and the microstrains of the samples In Fig.1 is presented
the diffractogram of Fe3O4 nanoparticles with adsorbed on their surfaces
an oleic acid layer
Fig.1. XRD diffractogram of Fe3O4 nanoparticles with adsorbed on
their surfaces an oleic acid layer
References
1. L.Vekas, D.Bica, O.Marinica, M.Rasa, V.Socoliuc, F.D.Stoian,
J.Magn.Magn.Mater, 289 (2005) 50
2. V.Kuncser, G.Schinteie, B.Sahoo,W.Keune, D.Bica, L.Vekas, G.Filoti, J.Phys.:Condens. Matter 19 (2007) 1-16
3. M.V.Avdeev, D.Bica, L.Vekas, O.Marinica, M.Balasoiu, V.Aksenov, L.Rosta, V.M.Garamus, A.Schreyer, J.Magn.Magn.Mater 311, (2007), 6-9.
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P- 2. ADVANCED MULTIFUNCTIONAL MATERIALS
P-2-01. Sisteme liante cu continut de MgO multifunctionale
Mohanu Ileana, Ionela Petre, Amzica Florin, Ilie Gabriela, Andreescu Ecaterina, Roxana Fechet
S.C.CEPROCIM S.A.
Abordări moderne in cercetarea materialelor de constructii sunt
orientate spre realizarea unor noi lianti performanti, cu implicatii benefice
asupra mediului. Una dintre acestea se refera la sistemele liante avand in
componenta oxid de magneziu reactiv. Prezenţa MgO în proporţii diferite
imprimă sistemului liant caracteristici specifice determinând
multifuncţionalitatea acestuia şi anume: densitate ridicată, rezistenţe
mecanice ridicate, rezistenţă la medii corozive, imobilizarea deşeurilor,
captarea CO2 din atmosferă.
In lucrare sunt prezentate rezultatele cercetarilor efectuate
pentru obtinerea unor sisteme liante pe baza de ciment portland cu
proportii variabile de MgO.
S-a urmarit mecanismul de hidratare al liantilor din acest sistem la
termene scurte si lungi precum si influenta compusilor de hidratare asupra
caracteristicilor sistemului intarit.
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P-2-02. New Pyrrolopyrimidine Derivatives under Ultrasounds Irradiation
Costel Moldoveanu,a Geanina Mangalagiu,b Dan Maftei,a Ionel I. Mangalagiu*a a “Al. I. Cuza”University, Carol I-st Bd., No 11, Iasi 700506, Romania. E-mail: [email protected] b National Colleague, Iasi, Arcu Street, No. 4, Iasi, 700125
The literature describes a large variety of pyrimidine compounds
with different biological activities: anti-HIV, anticancer, antituberculosis ,
antimicrobial, antihypertensive, platelent, etc. The emphasis of this work
was to obtain pyrimidine derivatives using cycloimmonium ylides as
reactive species, under classical conditions and under ultrasounds
irradiation. The reaction pathway involves, a Huisgen 3+2 dipolar
cycloaddition of ylides to dipolarophiles (activated alkynes).
The problems of stereo- and regiochemistry involved in these
types of cycloadditions are discussed. Under ultrasounds irradiation the
reaction times decrease, the amount of solvent used decrease also and,
the yields are much better.
Acknowledgements: to CNCSIS Bucharest, grant no.
1155/2006, for financial support.
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P-2-03. SDM in Advanced Nanomaterials fine-tuning for some Perovskites type AHE Study
S. Mohorianu, F.-V. Rusu, M. Lozovan National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd., Iasi,700050, Romania. e-mail: [email protected]
Nanostructured materials that have tailored properties to achieve
improved mechanical, electrical, optical, magnetic and other functional
properties are now essential for future applications in the current industrial
manufacturing. The continuous evolution in the actual technology of
nanomaterials requires a careful understanding of chemical and physical
properties of materials, structures and processes at the micro- and
nanoscale. The major research objectives in advanced nanostructured
and multifunctional materials are still the modelling, the design, the
characterization and the fabrication of such a useful functional materials.
On the worldwide framework of computational nanotechnology [1]
it clearly appears that the software required to design and model complex
molecular structures become progressively available. In this context, in
the last few years we have also contribute [2, 3] to the effort of the
nanomaterial modelling and in the computer assisted design of some
magnetic nanomaterials. The atomic structure of nanostructured materials
is different than that seen in crystals or glasses because of the large
volume fraction >50% of grain boundaries or interfaces. Nanometer sized
materials (1 to 100nm) contain about 900 atoms if zero-dimensional
shape nanomaterial is considered. The magnetic permeability, the
magnetic anisotropy, the electrical conductivity are strong and effectively
correlated with the grain size of the nanomagnetic material [4, 5].
In the present paper we describe how a Simulation and Design
Method (SDM) attempt, based on our last results, and are applied on two
perovskites type materials, La2/3Ca1/3MnO3 and La2/3SrMnO3 in order to
study the Anomalous Hall Effect (AHE).
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References
1. R.C.Merkle, Computational nanotechnology, Nanotechnology, vol.
2, p. 134, 1991 2. S.Mohorianu, M. Lozovan, Rom.Journ.Phys., Vol. 52, Nos. 3-4,
2007 p. 337. 3. S.Mohorianu, M. Lozovan, C. Baciu, JOAM, Vol. 9, No. 5, May
2007, p. 1499 – 1504. 4. J.Ivcov, The Halleffect in amorphous alloys of early and late
transition metals, Fizika A4 3, 1995 561-570 5. T.Fukumura, H. Toyosaki, K.Ueno, M. Nakano, T. Yamasaki and
M. Kawasaki, A Scaling Relation of Anomalous Hall Effect in Ferromagnetic Semiconductor and Metals, JJAP Express Letter, vol. 46, No. 26, p. L642-644
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P-2-04. New Polysilane - Diazine Materials
Ionel Mangalagiu,1* Dorina Mantu,1 Rodinel Ardeleanu,2 Gabriela Sacarescu,2 Mihaela Simionescu2, Liviu Sacarescu2 1. “Al. I. Cuza” University of Iasi, Organic and Biochemistry Department, Bd. Carol 11,700506 Iasi, Romania; e-mail: [email protected] 2. Institute of Macromolecular Chemistry “Petru Poni”, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania; e-mail: [email protected]
Oligo- and polysilanes form a specific class of materials, which
have been subjected to many investigations during the last decades. [1,2]
Some of their intriguing electrical properties are related to the specific ó-
electron delocalization which endow polysilanes directional conductivity,
strongest along the axis of the chain.[3,4] Among these, polyhydrosilanes
are a relatively new class with specific properties.[5,6] Recently[7] our
group discover a new class of hybrid polysilanes with N-allyl-
cycloimmonium salt skeleton.
This work describes the first synthesis of a new polymer
poly[methyl(H)-comethylphenylsilane] with pendant diazine heterocyle.
This material was obtained by catalytic addition of Si-H groups within a
poly[methyl(H)-co-methylphenylsilane] backbone to the N-heterocycle.
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This hybrid polymer was characterized by spectral analysis,
thermogravimetric analysis and gel permeation chromatography (GPC).
References
1. J. P. Wesson, T. C. Williams, J. Polym. Sci., Part A; Polym.
Chem. Ed. 1979, 17,2833.
2. R. West, L. David, P. I. Djurovich, K. L. Stearly, K. S. Srinivasan, H. J. Yu, J. Am. Chem.Soc. 1981, 103, 7352.
3. A.Herman, B. Dreczewski, W. Wojnowski, Chem. Phys. 1985, 98, 475.J. Roncali, Chem. Rev. 1992, 92, 711.
4. G. Sacarescu, R. Ardeleanu, L. Sacarescu, M. Simionescu, J. Organomet. Chem. 2003,685, 202-206.
5. J. E. Frommer, R. R. Chance, “Encyclopedia of Polymer Science and Engineering”,J.Wiley & Sons, New York 1986, Vol. 5.
6. R. Ardeleanu, I. Mangalagiu, G. Sacarescu, M. Simionescu, L. Sacarescu, Macromol.Rapid Commun. 2004, 25, 1231.
Acknowledgements: to Romanian Ministry of Research and
Education - MATNANTECH program, grant no. 36/2005, for financial
support.
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P-2-05. Average Size of A Places and Cation Disorder Effects on Transport Phenomena in
La0.54Ho0.11Ca0.35Mn1-xCoxO3Manganites
Mihail-Liviu Craus1,2, Carmen Mita3, Nicoleta Cornei3, Mihai Lozovan1
1 Institute of Research and Development for Technical Physics, Iassy, Romania,
2 Joint Institute of Nuclear Research, Dubna, Russia, 3 Chemistry Departament, “Al.I.Cuza” University, Iassy, Romania,
ABO3 simple perovskites, with A=rare earth elements and/or alkali
(earth) elements, B=Mn (or transition cation) exhibit a large decrease of
the resistivity in an applied magnetic field. Transport phenomena in
manganites, implicitly the transition temperature from metallic to insulator
state, can be controlled by hole doping and the average size of the A
places ( rA ). In agreement with Zener’s theory, the strength of double
exchange is determined by the Mn-O length (dMnO) and Mn-O-Mn angles
( ∠ − −( )Mn O Mn ). A part of the manganites are ferromagnetic, the
Curie temperature increases with band width, determined by dMnO
distances and ∠ − −( )Mn O Mn angles. The ferromagnetism and
transport behavior are correlated with the crystalline structure of
manganites. Tolerance factor (t=dAO / 2.d MnO ) is an indicator of the
departure of ideal structure of the simple perovskites. For an ideal cubic
structure t=1, while for distorted structure (due to the Jahn-Teller Mn3+
cation presence on B places) t≠1. If the A or/and B places are occupied by
more cations, local structure can be quite different by the observed
crystallographic structure. A strong dependence exists between the
Curie/transition temperature, on a side, and tolerance factor and chemical
degree (σ 2 2= −∑ y r ri i A A, , where yi is concentration of i cation on A
place, ri A, - radius of i cation on A place), on other side. The substitution
of Mn with Co should lead to disorder on B places, a local modification of
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the B-O distances and B-O-B angles, due to different crystalline radii of Mn
and Co cations. We will to investigate the influence of substitution of Mn
with Co on the crystalline structure and transport characteristics in
La0.54Ho0.11Ca0.35Mn1-xCoxO3 manganites. The samples were prepared by
sol gel method to improve the purity and homogeneity of the samples:
stoichiometric amounts of La2O3, Ho2O3, CaCO3, MnO2 and CoO (99.9%)
were dissolved in nitride acid. Citric acid and ethylene glycol were added to
the previous solution. The mixture was heated giving a black-brown powder.
The resulted powder was pressed, heated at 800°C 17 hours, grinded, cold
pressed and finally sintered in air at 1200°C for 8 hors. The Mn3+
/Mn4+
concentrations were determined, to establish the correlation between the
Jahn-Teller cation concentration, on a side, and the crystalline structure and
transport characteristics, on other side. The sintered samples were
investigated by XRD, to determine phase composition, atoms positions,
lattice parameters, microstrains and average size of coherent lattice blocks.
XRD data were handled by means of DICVOL, CellRef and a Rietveld type
programs (FullProf). Some different structures (unit cells) were tested by
means of FullProf program. It was established the samples contain only
simple perovkite phase; unit cell volume is changing with the Co
concentration. The resistance of the samples, depending on temperature
and intensity of the magnetic field, was also determined by four probes
method. A decrease of the transition temperature from metallic to insulator
state with Co concentration was observed. The La0.54Ho0.11Ca0.35Mn1-xCoxO3
manganites exhibit a large magneto-resistance near room temperature.
Average size of coherent blocks and microstrains determine the transition
temperature and the ratio between extrinsic and intrinsic magnetoresistance
components. The small polarons hopping and variable range hopping
mechanisms were tested.
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P-2-06. Synthesis, Structure and Properties of Potassium-Doped La0.54Ho0.11Sr0.35-yKyMnO3 Manganites
Nicoleta Cornei1, Carmen Mita1, Mihail-Liviu Craus2,3, Mihai Lozovan2, Francis Abraham4, Nathalie Tancret4, Olivier Mentre4
1 Chemistry Departament, “Al.I.Cuza” University, Iassy, Romania, 2 Institute of Research and Development for Technical Physics,
Iassy, Romania, 3Joint Institute of Nuclear Research, Dubna, Russia, 4Ecole
Nationale Supérieure de Chimie Lille, UCCS, Lille, France, [email protected]
Lantanum orthomanganites of general formula La1-xAxMnO3 (A=
alkali earth elements) are subjects of recent interest due to their
properties: insulator-to-metal transition, orbitals ordering, charges ordering
and colossal magnetoresistance (CMR). These compounds exhibit
ferromagnetic and antiferromagnetic ordering depending on the relative
concentrations of trivalent and tetravalent manganese ions. The magnetic
structure observed in these compounds can be understood by considering
the competing ferromagnetic and antiferromagnetic exchange
interactions. Highest CMR intrinsic effect was observed near the
ferromagnetic transition temperature TC, and hence the search for new
materials having TC near 300 K. Monovalent ions (K, Na or Rb) doped
lanthanum manganites show similar electrical and magnetic properties to
that of the divalent ion doped lanthanum manganites.
We studied the influence of the potassium concentration on the
structure and the physical properties for La0.54Ho0.11Sr0.35-yKyMnO3 (y =
0.0; 0.05; 0.1) manganites. The samples were obtained by sol-gel
method, using citric acid as gelifiant agent, and flux method using an
excess of KCl. The precursors (La2O3, Ho2O3, Sr and Mn acetates and K
nitrate, K chloride, respectively) were mixed in stoichiometric ratio.
Powders resulted from gel calcinations were presenter and finally sintered
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at 1200°C for 10 hours. For the flux method the mixture of the solid
precursors were melted at 900°C for 24 h in air atmosphere. The melt was
cooled and washed with hot water. The resulting black powder was dried,
pelletized, and sintered at 900°C for 24 hours in oxygen atmosphere.
Sintered manganites were monitored by X-ray analysis a
diffractometer Huber Guinier CAMERA 670 with Cu Kα.1 radiation,
electronic microscopy using a JEOL JSM-5300 microscop, electronic and
IR methods using a VSU-2P spectrophotometer and JASCO 660 Plus FT-
IR spectrophotometers, respectively. Lattice constants, space group,
positions of cations/anions in the unit cell were determined by using
DICVOL and FullProf programs. Magnetic and electrical measurements
were performed with a Foner type magnetometer and, respectively, by
means of four probe method, between 77 and 600 K. The samples
contained only orthorhombic phases (S.G. Pnma). The substitution of Sr
with K leads to a decrease of the unit cell volume and the increase of
Curie temperature. The dependence of the transition from metallic to
insulator (semiconductor) state on chemical composition was also
investigated. The average of the transition temperature from metallic to
isolator state is 220-230 K.
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P-2-07. New Coronands with Aromatic Arms
Ondina - Cecilia Florea, Ana-Maria Balan (married Zbancioc), Ionel Mangalagiu* “Al. I. Cuza” University, Organic Chemistry and Biochemistry Dep. 11 Carol I Bd.700506 Iasi-6, Romania, e-mail: [email protected]
Supramolecular chemistry1 is one of the most expansive field in
chemistry. Coronands are targets of high interest in supramolecular
chemistry, being used as “hosts molecules” for cations, anions or organic
molecules. We report herein the synthesis of a new type of coronands
with aromatic arms using alpha-halogenated dihydroxy-acetophenone
units in reaction with aromatic dicarbonyl chloride. The structures of all
new compounds were confirmed by elemental and spectral analysis (IR,
1H RMN, 13C RMN, COSY, HMQC, HMBC)
.
Acknowledgements: to Romanian Ministry of Research and
Education – MATNANTECH program, grant no. 36/2005, for financial support.
References:
1. Godbert N., Batsanov A.S., Bryce M.R., Howard J.A.K., J. Org. Chem., 66, 3313, 2001.
2. Mertens I.J.A., Jenneskens L.W., Vlietstra E.J., van der Kerk-van Hoof A.C., Zwikker J.W., Smeets W.J.J., Speak A.L., J. Chem. Soc., Chem. Commun., 1621, 1995.
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P-2-08. Martensite-austenite and Ferromagnetic-paramag-netic Transformations in Ni2-xAxMn1-yByGa1-zCz (A, B=Co; C=Al) Heusler Alloys
Mihail-Liviu Craus1,2 , Viorel Dobrea1, Mihai Lozovan1 1 National Institute of Research and Development for Technical
Physics Iassy, Romania, 2 Joint Institute of Nuclear Research, Dubna, Russia,
Ni2MnGa Heusler alloy is known as potential smart material. At
room temperature it has a L21 type structure, undergoing a martensitic
transition (TM) at lower temperatures. Some authors have classified Ni-
Mn-Ga Heusler alloys on the martensitic transformation temperature and
Curie temperatures: first group formed by alloys with TM below room
temperature and TC, second group with TM around room temperature and
third group with TM>TC. The partial substitution of Ni with Mn leads to an
increase of the transition temperature and a decrease of the Curie
temperature. The Ni2-xMn1+xGa alloys have a complex tetragonal structure
at room temperature. The substitution of Ga with Al can change the
crystalline and magnetic structure of Heusler alloys: Ni2MnAl is
antiferromagnetic for a B2 (CsCl type, with Mn and Al randomly distributed
in the center of the cube) structure and ferromagnetic for a L21 (BiF3 type
with Mn and Al ordered distributed in the cube center) structure. A
dependence between the transition temperature and the magnetic field
was observed for some Ni2+xMn1-xGa (x=0.19) and Ni2+yMnAl1-y (y=0.12)
Heusler alloys. For some Heusler alloys a dependence of the transition
temperature on the applied magnetic field was observed.
We intend to put in evidence the structural change and the
dependence between the applied magnetic field on a side, and the
transition temperature, on other, for the Ni2-xAxMn1-yByGa1-zCz (A, B=Co;
C=Al) Heusler alloys.
The Ni2-xAxMn1-yByGa1-zCz (A, B=Co; C=Al; x=0.25; y=0.125;
z=0.125) Heusler alloys with stoichiometric compositions were melted in a
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furnace in Ar atmosphere, homogenized for 72 hours at 1273 K and aged
at 1073 K for 48 hours followed by air cooling. The alloys phase
composition and structural parameters (lattice constants, texture,
microstrains, average size of the coherent blocks were investigated by X-
ray diffraction at room temperature. XRD data were handled by DICVOL,
CeckCell and FullProf programs. The aged alloys are formed by a mixture
of tetragonal/orthorhombic and cubic phases. Only Al substituted alloys
contain a foreign phase (Al-rich). Large microdistortions and small size
coherent blocks were observed. The magnetic measurements were
performed between 77 K and 673 K, by using a Foner type magnetometer
(Hmax = 4 kOe). The Curie and martensitic transformation temperatures
were determined from the variation of specific magnetization with the
temperature. Ni2MnGa alloys have a Curie temperature around 50oC and
a transformation point from austenite to martensite below room
temperature. The presence of the Co in investigated Heusler alloys lead
to an increase of the Curie temperature. In the investigated range of
temperatures no martensite-austenite transition was observed for the
samples with Co. The substituted with Al alloys have Curie temperatures
around 50oC and transition point below room temperature, depending on
the Al concentration.
A correlation between the type of substitution, on a hand, and the
microstrains and size of coherent blocks was established. For the
Ni2MnGa Heusler alloys a dependence of Curie temperature on the
intensity of the magnetic field was observed.
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P-2-09. New Coronands with Aliphatic Arms
Ana-Maria Balan (married Zbancioc), Ondina-Cecilia Florea, Ionel Mangalagiu* “Al. I. Cuza” University, Organic Chemistry and Biochemistry Dep. 11 Carol I Bd.700506 Iasi-6, Romania, e-mail: [email protected]
During the last decades [1, 2], supramolecular chemistry became
a real paradigm in organic chemistry. We report here, synthesis of a new
type of oxacoronand using aromatic dihydroxi compounds and
polyfunctionalized reagents of type haloacyl chloride.
The novelty of these reactions consists in using alpha-halogenated
dihydroxy-aceto-phenone units which allow further a synthetic route of
obtaining ligands possessing multiple binding sites with many applications.
Acknowledgements: to Romanian Ministry of Research and Education –
MATNANTECH program, grant no. 36/2005, for financial support.
References
1. J. M. Lehn, Angew. Chem., Int. Ed. Engl., 1988, 27, 89; ibid,
“Supramolecular Chemistry – Concepts and Perspectives”, VCH, Weinheim, 1995.
2. T. Bogaschenko, S. Basok, C. Kulygina, A. Lyapunov, N. Lukyanenko Synthesis 2002, 15, 2266-2270.
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P-2-10. Effect of Ce and/or Gd Dopping on the Micro-structure Properties of PT Type Ceramics
M.Balasoiu1, V.Tripadus1, M.-L.Craus2, A-M. Moisin3
1 “Horia Hulubei” National Institute for Physics and Nuclear Engineering Bucharest, Romania; [email protected]
2 National Institute of Research and Development for Technical Physics, Iasi, Romania;
3 INCDIE ICPE-CA, Bucharest, Romania;
Advanced ceramic materials are now well established in many
areas of every day use. The improvements in performance, service life,
savings in operational costs and savings in maintenance are clear
evidence of the benefits of advanced ceramic materials. Life
expectancies, now in years instead of months with cost economics in the
order of only double existing component costs, give advanced ceramics
materials a major advantage. The production of these advanced materials
is a complex and demanding process with high equipment costs and the
requirement of highly specialised and trained people. The ceramic
materials of tomorrow will exploit the properties of polycrystalline phase
combinations and composite ceramic structures, i.e. the co-precipitation
or inclusion of differing crystalline structures having beneficial properties
working together in the final compound. Neutron scattering methods are
intensively used to obtain structural information about these materials.
We will analyze the structure, grain morphology and porosity of
sample of two different perovskite type systems lead titanate with rare
earths substitutions prepared at different temperatures by means of XRD
and small angles neutron scattering (SANS).
Conventional -2 X-ray diffraction scans using CoK radiation
were recorded in order to identify the crystallographic phases and to
determine the average coherent sizes and the microstrains of the
samples. Some lead titanate with Ce/Gd substitutions, with a structure
similar to makedonite were obtained by ceramic standard technology. The
structure and the phase composition of the samples were tested by
means of XRD.
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Sintered samples have a tetragonal structure, similar to
makedonite (PbTiO3) (s.Fig.1). PT have a phase transition from cubic to
tetragonal structure, which determine the appearance of large strains and
a decrease of mechanical stability. The doping with trivalent or tetravalent
cations as Gd3+
, respectively, Ce4+
etc seems to enhance the mechanical
stability and the to preserve the electric properties. We obtained
information concerning the geometry of the pore space, chemical
aggregation and defects in investigated materials. Small grain sizes
and/or high densities of inner pores could lead to a spectacular changes
of the mechanical properties.
Figure 1 The difractograms of: 1) PT(Gd) sintered at 1180ºC / 1h (green) (experimental) and 2) PbTiO3 (tetragonal structure, calculated with FullProf)
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P-2-11. Steroid Analogous through Ultrasounds Assisted Reactions
Vasilichia Bejan, Maria Caprosu, Ionel Mangalagiu* “Al. I. Cuza” University, Organic Chemistry Dep., 11 Carol I Bd., 700506 Iasi-6,Romania. e-mail: [email protected]
Literature describes a large variety of phthalazine compounds
with different biological activities: anticancer, antimicrobial,
antihypertensive, platelent aggregation inhibitor, etc.
A facile way to obtain diazine derivatives, are using cycloimmonium
ylides, as reactive species in organic synthesis. Considering the steroid
skeleton as the pharmacophoric group for the activity, in this work we
aimed to obtain new steroid analogous with potential antimicrobial activity,
having diazine heterocycles incorporated.
In order to synthesize the desired steroid analogous with
phthalazine skeleton incorporated, first we obtained the corresponding
cycloimmonium salt (1) which in alkaline medium (Et3N) generated the
ylide (2) in situ. Dienophiles, reacts with ylides (2) giving the steroid
analogous (3). The [3+2] cycloaddition occurs with high stereospecificity
and no formation of other isomers was observed. Under ultrasounds
irradiation the reaction times decrease, the amount of solvent used
decrease also and, the yields are much better. Antimicrobial activity was
tested in vitro on germs Gram positive (Staphylococcus aureus Oxford,
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Sarcina luteea, Bacillus subtillis, Bacillus cereus), germs Gram negative
(Escherichia coli, Klebsiella spp., Acinetobacter spp., Pseudomonas
aeruginosa), fungus (Candida albicans).
Acknowledgements: to Romanian Ministry of Education-
BIOTECH program, grant no. 49/2005 and, to CNCSIS Bucuresti, grant
no. 1155/2006 for financial support.
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P-2-12. 1, 2-Diazine with Biological Activity,
Roxana M. Butnariu (maried Tucaliuc), Maria Caprosu, Gabi Drochioiu, Ionel Mangalagiu “Al. I. Cuza” University, Organic Chemistry Dep., 11 Carol I Bd., 700506 Iasi-6,Romania. e-mail: [email protected]
The interest for synthesis of heterocyclic compounds is receiving
much attention due to their potential biological activities. The emphasis of
this work was to obtain new diazinic derivatives with potential biological
activities. In this reaspect, the cycloimmonium ylides (generated in situ
from the corresponding salts), was treated with variously non-symmetrical
substituted dipolarophiles. The reactions occurs as [3+2] cycloadditions
and involves additionl regiochimical problems.
The structure of the new compounds was proved by elemental
and spectral analysis (SM, IR, 1H NMR, 13C NMR, and two-dimensional
experiments 2D-COSY, 2D-HETCOR (HMQC), long range 2D-HETCOR
(HMBC)); the in vitro biological test was realized for the new heterocyclic
compounds synthesized.
Acknowledgements: to CNCSIS Bucuresti, grant no. 1155/2006,
for financial support.
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P-2-13. Poly (Aspartic Acid) Template for a Bioactive Structure
Aurica P. Chiriac, Loredana Elena Nita, Iordana Neamţu “Petru Poni” Institute of Macromolecular Chemistry Grigore Ghica Voda Alley, no 41A, 700487 Iasi,
ROMANIA
Poly (aspartic acid) belongs to the new family of biodegradable,
environmentally friendly poly(amino acid) polymers in which amide linkages
extend the chain. The biodegradability as well the chelating properties of
partially derivative poly (aspartic acid) determines the numerous
applications of this polymer. Thus, peptide hormone-polyamino acid
complexes can be used in medicine, for example for the therapy of
hormone-sensitive tumours, such as breast and prostate carcinoma, benign
prostate hypertrophy and in gynaecology for the treatment of endometriosis,
hysteroscopy and for the treatment of fertility disorders. The poly(amino
acid) – peptide hormone complexes can furthermore be prepared with a
controllable hormone content by lyophilization of the aqueous solutions. By
means of the nature and the molecular mass of the poly(amino acids) –
poly(aspartic acid) –, by incorporation of hydrophobic amino acids into the
polymer structure or by partial esterification, the release rate of the active
compound can be controlled. As it is well known Zeta potential
measurements give information about the overall surface charge of the
particles and how this is affected by changes in the environment (e.g. pH,
presence of counter-ions, and adsorption of proteins). Charge shielding by
hydrophilic groups can be used to predict the effectiveness of the barrier
function against opsonisation in vivo. Zeta potential is also used to
determine the type of interaction between the active substance and the
carrier; i.e. whether the drug is encapsulated within the body of the particle
or simply adsorbed on the surface. This is important because adsorbed
drug may not be protected from enzymatic degradation, or may be released
very rapidly after administration. The study presents the poly(aspartic acid)
characterization from the viewpoint of its zeta potential measurements in
order to be used as template for a bioactive compound preparation.
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P-2-14. Microstructure of La0.54Ho0.11Sr0.35-xNaxMn1-yCuyO3
Manganites
Mihail-Liviu Craus1,2, Nicoleta Cornei3, Carmen Mita3 1 Institute of Research and Development for Technical Physics,
Iassy, Romania, [email protected] 2 Joint Institute of Nuclear Research, Dubna, Russia, 3 Chemistry
Departament, 3 “Al.I.Cuza” University, Iassy, Romania,
Manganese perovskites, Re1-xAlkxMnO3 (Re= rare earth; Alk=
alkali earth/alkali elements) were intensively investigated in the last ten
years, due to the observed colossal magnetoresistance (CMR) near
ferromagnetic-paramagnetic transition temperature. The CMR effect is
most prominent for x≈0.3. Spin structure and electric properties are
controlled by Zener mechanism, despite some experimental results,
which can not be explained by means of double exchange theory. We
will establish a correlation between the radius and distribution of the
cations in the unit cell, on a side, and physical properties on other side
for La0.54Ho0.11Sr0.35-xNaxMn1-yCuyO3 manganites. The samples were
obtained by sol-gel method, using oxides (La2O3, Ho2O3; 99.99% purity),
Sr and Mn acetates (99%) and Cu nitrate (99%). Oxides and acetates
were solved in an aqueous solution of nitric acid, respectively, an
aqueous solution of acetic acid. The gel was obtained by adding an
aqueous solution of citric acid to a stoichiometric mixture of precursors.
Powders resulted from gel calcinations were presintered and finally
sintered at 1200°C in air. Presintered and sintered manganites were
monitored by X-ray analysis to determine begin of solid-state reaction,
the phase composition, the parameters of unit cell, the average size of
coherent blocks and the microstrains. XRD data were obtained with a
diffractometer with data acquisition system and Cu anode X-ray tube, at
room temperature, and handled with DICVOL, CELLREF and
FULLPROF programs. Mn-O distances, Mn-O-Mn bonds angles and
atoms positions in the unit cell were determined. Magnetic and electrical
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measurements were performed with a Foner type magnetometer and,
respectively, by means of four probe method, between 77 and 600 K.
The sintered samples contain only perovskite phases. A variation of the
average size of the coherent blocks and microstrains with Cu and Na
concentrations was observed. The substitution of Sr with Na leads to a
decrease of the unit cell volume, while the Cu substitution produced a
non-monotonous variation of the unit cell. We discussed the
dependence between the tolerance factor (experimental and calculated),
the chemical disorder degree and the band width, on a side, and the
Curie temperature on other side. The dependence of the transition from
metallic to insulator (semiconductor) state on chemical composition was
also investigated.
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P-2-15. Ferromagnetic Materials Synthesized in Silica Matrix
N. Suliţanu, V. Nica, F. Brînză Solid State and Theoretical Physics Dept., Faculty of Physics, Al.I.Cuza University, 700506, Iasi, Romania
The importance of nanosized and nanostructured magnetic
materials is established from many times ago. The played role is
sustained by new magnetic properties relieved at nanoscale. Various and
new application was developed e.g. materials for drugs carrier, contrast
agents for magnetic resonant images, EMI protective paintings,
information storage. In this paper we intend to present new obtained
results in synthesis of nanosized clusters of ferromagnetic elements, Fe,
Ni and Co and their various alloys. A chemical method was used in order
to obtain embedded nanoclusters of mentioned materials in a silica matrix.
A new shape of clusters is obtained and similarity with silicon and
silicon dioxide diffusion in some steels can explain those shapes. A
magnetic property was also investigated. Using proposed method, new
shapes of nanosized ferromagnetic clusters can be obtained and used for
new micro and nanoactuators application.
References
1. T. Sourmail, Near equiatomic FeCo alloys: constitution, mechanical and
magnetic properties, Prog. Mater. Sci., 2005:50, p816-880. 2. F. Johnson, C.Y. , Um, M.E., McHenry, H. , Garmestani, JMMM
Volume 297, issue 2, February 2006, 93-98. 3. F. Hamadache et all, J. Mater. Res., Vol. 17, No. 5, May 2002.
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P-2-16. Synthesis and Magnetic Properties of Fe3O4 Nanoparticles Embedded in a Zeolite Matrix
N. Suliţanu, F. Brînză Department of Solid State Physics and Theoretical Physics, “Al.I.Cuza” University of Iasi, Blvd. Copou 11, 700506 Iasi, Romania
In this paper we presented a theoretical and an experimental method
for embedding magnetite (Fe3O4) in a porous zeolite (ZSM-5 and
mordenite) using chemical and electrochemical methods.
Zeolites are crystalline aluminisilicate materials used extensively as
shape-selective and acid catalysts in many different industries. The
topology of the frameworks of these materials creates pores and channels
of varying sizes (for different zeolite materials) that admit or exclude
different adsorbate molecules. The channel systems in the zeolite
materials can range from simple unidimensional channels to complex 3D
pores networks.-
The structure of zeolites with pores or channels of well-defined size
are particularly suitable for the study of magnetic properties of ultrafine
particles of Fe3O4 introduced into the zeolites structure using chemical
and electrochemical methods. We obtained experimentaly a hysteresis
Magnetic
moment of
Fe3O4
electrodeposited
nanoparticles in
ZSM-5 zeolite.
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loop for a zeolite sample impregnated with Fe3O4, using electrochemical
method for embendding feromagnetic sample.
At low fields the sample have the tendance to behave like a
ferromagnetic substance, but, with incrising field, appear a diamagnetic
component (who alternate proportional with the field but with minus sign)
which tend to changes the hysteresis.
References
1. Ch. Baerlocher, W.M. Meier, D.H. Olson, Atlas of Zeolite Frame-
work Types, Elsevier, 2001. 2. Ch.J.-M.Y. Houssin, Nanoparticles in zeolite synthesis, Thesis,
Tech. Univ. Eindhoven, Netherland, 2003. 3. I.Zhang, A. Manthiram, Fine Magnetic Particles in Layered
Silicates and Zeolites, IEEE Transactions on Magnetics, 31, 6, 1995.
4. Despina Mehedintu Davis, Electrodeposition of magnetic nanowires and nanotubes, Thesis, Texas Tech. University, USA, 2005.
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P-2-17. Multilayered Thin Films with Selective Spectral Properties
Felicia Iacomi1, R. Apetrei1, G.M. Rusu1, C. Baban1, E.Budeanu2, M. Purica2, D. Luca1 1 “Al.I.Cuza” University, Faculty of Physics, Iasi. Romania 2 National R&D Institute for Microtechnologies, Bucuresti,
Romania
Multilayer structures formed from Al, SiO2, TiO2, Ag thin films were
deposited on glass substrates by using vacuum thermal evaporation and
RF magnetron sputtering methods.
The structure and morpho;ogy of thin films were studied by
means of X-ray diffraction (DRON2, CuKα) and atomic force mycroscopy
(home-made equipment). Transmittance and reflectance spectra of thin
films were analysed by using a STEAK-ETA-OPTIK instrument.
The obtained multilayerd structures exhibit an UV-Viz
transmittance maxima, more intence and more sharp as the thickness of
dielectric thin films and substrate temperature increase.
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P-3. NATURAL AND SYNTHETIC ZEOLITES
P-3-01. Compositional Particularities of the Piatra-Verde Slanic Volcanic Zeolitic Tuffs. Hump Effect.
Bogdan-Ion Mocanu*, Nicolae Naum**, Cristian Lungu*** * Refinery Petrobrazi, Brazi, Prahova district,
[email protected] ** Management Programs National Centre from Education and
Research Ministry, No.21-25 Mendeleev street, Bucharest, [email protected]
*** National Institute for Lasers Plasma and Radiation Physics, Magurele, [email protected]
Using up-today analysis methods, this paper confirms existence
like majority phase of the natural zeolite – clinoptilolite, to the prejudice of
the heulandite, and proves the presence alongside of the clinoptilolite, an
amount fine crystallizated silica in the Piatra-Verde Slanic zeolitic tuffs.
This quantity of the fine crystallizated silica causes the appearance
an „Hump effect” on the X-ray diffraction patterns in the range of the 15-
35° (2θ angles) and confers to this zeolitic tuff an very good pozzolanic
activity.
Pozzolanic activity together with the good ionic exchange capacity
could represent the premises a complex utilizations of this clinoptilolitic
tuff, such as nuclear decontamination of a contaminated with
radionuclides streams and theirs safety stocking.
Key-words: clinoptilolite, heulandite, fine crystallizated silica,
pozzolanic activity.
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P-3-02. Could the ESR Investigation Support the Presence of Au Nanoparticles Stabilized in Zeolites ?
S.Farcas, A.Popa, L.M.Giurgiu, Z.Qu(1) , E.Roduner(1)
National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, P.O.Box 700, Romania (1)Institut fur Physikalische Chemie, Universitat Stuttgart, D-70569 Stuttgart, Germany [email protected]
Zeolites are very promising to act as support for stabilizing
metallic particles because of the crown-ether-like ring structures in their
cages and channels. In this communication we used ESR spectroscopy to
study the possible anchoring of Au nanoparticles in Y-type zeolites. In a
previous paper we have reported for the first time the ESR observation of
the square-planar complex of Au(II) with four nitrogen atoms of two
ethylenediamine ligands in the super cage of the zeolite [1].
In the temperature range 4 – 300 K a sharp ESR signal was
observed in Au/NaY zeolites pretreated with oxygen at different
temperatures. The characteristic spectral parameters g = 2.008 and ∆H =
8 G are almost temperature independent.
A discussion is given concerning the possibility that this
resonance to be attributed to the conduction electron spin resonance
(CESR) of Au nanoparticles. Kawabata’s conditions and the quantum size
effects are taken into account [2].
References
1. Z.Qu, L.M.Giurgiu and E.Roduner, Chem. Commun. 26, 2507 (2006)
2. L.M.Giurgiu, 5-th National Conference “New Research Trends in Material Science”, Sibiu, Romania, 2007 – invited lecture
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P-3-03. Utilization of Natural Clinoptilolite for Reducing the Risk of Gall Stones Renal Calculus and Tumor Formation
N. Izmirova1, E. Djourova2, B. Aleksiev2, M. Baeva3, P. lagoeva4, P. Uzunov5, I. Tomova6, A. Boyanova3, Tz. Mircheva4
1 “Clinalex - Nedylka Izmirova” Pte, 2 SU “St. Kliment Ohridski” Faculty of Geology and Geography, 3 BAS Institute of Solid State Physics, 4 Sofia hospital for active treatment of onco-patients,
5 SU “St. Kliment Ohridski” Faculty of Physics, 6 “First obstetrics and gynecology hospital” St. Sofia,Sofia,
Bulgaria
The present study offers a possibility to use natural clinoptilolite
(Cpt) as a means for reducing the risk of tumor, gall-stones, and renal
calculus formation. It is based on the result of optical investigation of
central openening spherulites (Sph) in human urine of ill and healthy
organism /1/.
In experiments carried out on mice during a period of 24 months,
we observed that there exists a certain tendency toward reduction of
tumor (appearing spontaneously) formation in mice treated orally or
dermal with Cpt when compared to the untreated mice, especially in
regards to the Limphoma - Lymphosarcoma and Reticulum-cell Neoplasm
Type B /2/.
Comparative analysis of the XRD patterns of Cpt and Sph shows
that in most cases d-spaces of Sph fall into intervals or coincide with the
d-spaces of Cpt. Most probably in analogy with Cpt, Sph in human
organism exhibit adsorption, ion-exchange, catalytic and molecular sieve
properties.
Sph develop and reproduce normally when the symmetry and the
composition of the growth environment are not influenced by endo- and
exogenic factors. In case of intoxication of the organism the symmetry and
composition of the environment it changes. Then the polymorph
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transformation becomes slower, the central pores of the Sph close. The
latter tighten and display not typical for them processes – capsulation and
concentric growth. In the concentric layer thus formed radial orientation of
the crystals which is a predisposition for gall-stones and renal calculus.
For reducing the risk of tumor, gall-stones, and renal calculus formation
per oral application of natural Cpt alone or in combination with vitamin C is
recommended.
References
1. N. Izmirova, B. Aleksiev, Method for Diagnosis, Patent №
63679/1999, BG. 2. P. Blagoeva, Z. Gendgev, N. Izmirova, and Tz. Mircheva,
Investigation for Carcinogenesis of Natural Clinoptilolite on mice and rats, Report to the Ministry of Science and Education, № 54919/20.12.2001, Sofia, Bulgaria.
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P-3-04. On the Use of Zeolitic Volcanic Tuff in the Decontamination of Wastewaters
Doina Humelnicu1, Evelini Popovici2
1 “Al.I. Cuza” University, Iasi, Faculty of Chemistry, Dept. of Inorganic and Analitycal Chemistry, [email protected]
2 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
The significant cation exchange capacity of natural zeolites and
their availability at the low cost are the main reason useful for
radionuclides immobilization and implicit decontamination of radioactive
wastewaters.
Natural zeolite volcanic tuff was tested for its ability to remove
radioactive ions (UO22+
and Th4+
) from wastewaters. The sorption
behavior of U(VI) and Th(IV) from aqueous solutions has been studied in
the absence of the ionic competition as a function of contact time,
radioactive ions concentration, temperature and pH.
Distribution coefficients of uanium and thorium on zeolitic volcanic
tuff were measured using batch technique.
The apparent thermodynamic parameters ∆Ho and ∆S
o for the sorption
process were calculated. The results obtained indicate that this process is
endothermic. The negative values obtained for ∆Go and the increase of these
absolute values with increasing temperatures are consistent with the fact that higher
temperatures favor the sorption process.
References
1. D. Humelnicu, G. Drochioiu, M.I. Sturza, A. Cecal, K. Popa – J. Radioanal. Nucl. Chem., 270, (2006), 637.
2. S. Akyil, M. Eral - J. Radioanal. Nucl. Chem., 266, (2005), 89. 3. A. Kilincarslan, S. Akyil - J. Radioanal. Nucl. Chem., 264(2005), 541. 4. E. Popovici, D. Humelnicu, C. Hristodor – Rev. Chim. Bucharest,
57, (2006), 675.
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P-3-05. Synthesis and Characterization of Ferrierite/ZSM-35 Type Zeolite in the Presence of Ethylenediamine
Ioana Droahna, Iuliean Asaftei, Nicolae Bilba ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
Ferrierite is an intermediate port zeolite between small port (8-
MR) zeolites of 0.3-0.5 nm effective diameter and the large port (12-MR)
zeolites which sorbs the cyclic hydrocarbons. The FER framework
contains a 2-D system of intersecting channels, one straight, along [001]
direction with 10-ring elliptical openings (0.54x0.42 nm) and the other
(cages) parallel to [010] direction with 8 ring openings (0.48x0.35 nm). At
the 2-D intersections there are pseudo-spherical cavities (“ferrierite cage”)
with free diameter of 0.6-0.7 nm and with two 8-MR openings. FER is of
interest as a molecular sieve and of acid catalyst due to channels formed by
10-MR, high SiO2 /Al2O3 ratio (6-60), thermal stability and to good chemical
stability in either acidic or basic solution. FER possesses interesting
adsorption properties, exhibits an excellent shape-selectivity in the
isomerization of n-butene to iso-butene (an intermediate for the production
of MTBE, an additive in lead-free gasoline), in skeletal isomerization of 1-
hexene and a good activity for the selective reduction of NOx.
FER and ferrierite-type zeolites (Sr-D, ZSM-35, Fu-9, ISI-6, Nu-
23, ZSM-38) have been prepared in the reactant system without or with
organic templates. Synthesis of Sr-FER from aqueous gels in the
temperature range 340-3800C has been first reported by Barrer and
Marshall in 1964. Zeolite ZSM-35 was first synthesized in aqueous gels in
presence of organic compounds as template by Plank et al. in 1977. ZSM-
35 is isostructural with natural FER but have unit cell parameter a=1.892
nm instead of 1.92 nm and in the powder DRX pattern the strong line at
1.13 nm present in FER is absent or is of very low intensities. Most of the
reports on synthesis of FER required high crystallization temperature and
products were of low SiO2/Al2O3 ratio. Usually, FER/ZSM-5 zeolite is
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synthesized in an alkaline system containing different organic compounds
as templates, including pyrrolidine, pyridine, n-alkylamine, piperidine,
TMAOH, TPABr, 1,4-dimethylpiperazine, 1,4-butyldiamne, ethylenediamine,
diethanolamine, cyclohexyldiamine, choline, morpholine, dioxan,
hexamethyleneimine.
In this study FER/ZSM-35 materials with good phase purity and
crystallinities were prepared by hydrothermal synthesis using mixtures of
sodium silicate, aluminium sulphate, sulphuric acid and distilled water in
the presence of EDA as template in an autoclave at 1800C for 1 to 6 days.
The zeolites obtained were characterized with XRD, SEM, NH3/TPD, N2
sorption and n-hexane, benzene, cyclohexane, methanol and water
adsorption. XRD patterns have confirmed FER structure and are
consistent with a literature data. Close examination of FER/ZSM-35 show
the absence or presence of a very weak line at 1.13-1.15 nm. The
intensity of the peak appearing at 25.3o (2θ) was selected as a measure of
crystallization degree. According to their SEM photos, FER/ZSM-35
samples appear as a rectangle-shaped, sheetlike morphology. The N2
sorption isotherms at 77 K belongs to Langmuir type I, the surface area
being in the range 270-380 m2.g
-1 and the pore volume of
0.15-0.18 mL.g-1
. The NH3-TPD curve of the acid form of FER/ZSM-35
present two peaks of ammonia desorption: one at 2800C (in the range of
200-4000C) specific to weak acid sites and another at 600
0C (in the range
of 400-9000C) specific to strong acid sites.
The ability of synthetic FER/ZSM-35 to selectively sorbs normal-,
branched chain and cyclic hydrocarbons (non-polar compounds) and
water and alcohols (polar compounds) is possible due to the presence of
10-MR in channels and to surface hydrophilic/hydrophobic character.
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P-3-06. Synthesis of SnO2 Controlled size Nanoparticles in Zeolite Matrices
Aurelia Vasile, Eveline Popovici
''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
Zeolites have open crystalline structures with well-defined and
well-ordered channels of nanoscale dimensions which provide an ideal
environment for synthesizing and stabilizing clusters and nanoparticles.
Synthesis and stabilization of semiconductor nanoparticles encapsulated
in different zeolitic hosts has been studied for CdS, PbS, ZnS, MnS, ZnO.
The impregnation, ion exchange, heat dispersion, chemical vapour
deposition or direct synthesis for preparing of zeolite-nanoguest systems
are the main methods.
This research work was focused on the synthesis of SnO2
nanoparticles inside the channels of the silicalite-1 using the following
methods: the conventional method of impregnation, the original modified
impregnation method and in situ formation during silicalite-1 synthesis.
Influence of synthesis parameters, tin content of the impregnation
solution, temperature and duration of the calcination on in situ SnO2
nanoparticles formation was studied. The samples were characterized by
X-Ray powder diffraction method (Phillips diffractometer using filtered
CuKα radiation), SEM (JEOL-JSM-6300 scanning microscope), DRS UV-
VIS (Shimadzu UV 2401PC spectrophotometer with a integrating diffuse
reflective sphere and BaSO4 as reference), FT-Raman (Nicolet Nexus FT-
Raman spectrometer) spectroscopy. DRS UV-VIS spectra showed for all
synthesized samples an absorption edge in the range 250~270 nm that is
significantly blue shifted compared to that of bulk SnO2 (358nm). The blue
shift of the absorption edge indicates the presence of nanosized SnO2.
The blue-shift of the absorption edge in the DRS UV-VIS spectra is most
pronounced for the nanoparticles SnO2-silicalite-1 systems prepared by in
situ formation of SnO2 nanoparticles. The presence SnO2 nanoparticles
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encapsulated in the silicalite-1 pores was demonstrated and by the
Raman spectroscopy. The intensity of the peak of 634 cm-1
, due to the
nanosized SnO2 formation, is higher in the case of in situ method
comparatively with the other studied methods. It is found that all used
methods lead to nanoparticles SnO2-zeolite systems formation, but in situ
formation during silicalite-1 synthesis method is preferable because it is
more simple and efficient. The study suggested that a Silicalite-1 channel
system is a good confinement environmental for formation and
stabilization of SnO2 nanoparticles. In situ formation during silicalite-1
synthesis of the SnO2 nanoparticles is one-step preferable method.
Acknowledgments. The authors are grateful for the
MATNANTECH financial support, Project CEEX No.1/S1/2005.
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P-3-07. Synthesis and Properties of Au and Pt-Au Nanoparticles Dispersed in Nanoporous Materials
Eveline Popovici, Aurelia Vasile, Emiliana Dvininov ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
The stabilization of metallic nanoparticles inside the well-defined
microporous and mesoporous materials lead to an interesting class of
organic-inorganic hybrids with important catalytic properties. Among the
transition metals, gold and palladium are intensively studied. Gold had, for
a long period of time, the reputation of being catalytically inactive. Haruta
[1] demonstrated that nanosized gold particles, when are deposited on an
oxide support, exhibit surprisingly high catalytic activity in oxidation of
carbon monoxide at/or below ambient temperature.
Preparation of supported gold and palladium catalysts can be
achieved by the following different traditional routes: (i) impregnation of a
performed support with those salt solutions followed by drying and
reduction [2]; (ii) cation exchange with support by cationic gold and
palladium complexes followed by washing, drying and reduction [3]; (iii)
coprecipitation of hydroxides of both support and gold followed by drying,
calcination and reduction [4] deposition-precipitation of metal hydroxides
to a suspension of the support followed by drying, calcination and
reduction [5] and (iiii) chemical vapor deposition of a volatile compound of
gold and palladium to a high area support through an inert gas. Another
possibility for gold nanoparticles obtaining is in situ reduction of
chloroaurate ions (AuCl4-) via silanol groups present in inner surfaces of
organo-functionalized MCM-41 or on the surface of amorphous silica.
Metal nanoparticles embedded in titania - matrices could be obtaining by
photo-catalytic reduction of Pd2+
and Au3+
ions under mild conditions.
In this paper, we report the synthesis and characterisation of Au/,
Pd-Au/ and Pt-Au/ nanoparticles dispersed into channels system of the
mordenite (MOR). While Au3+
is a metal cation that is very easy to reduce,
gold nanoparticles are the most difficult to disperse and to anchor in
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zeolites [1-5]. The hydrogen form of the zeolites are characterised by high
dispersion of the metal and the high thermal stability of the obtained
nanoparticles, explained by chemical anchoring of metal clusters by the
Brønsted sites of the framework. Based on these properties of the zeolites
in the present study we have chosen to employ the H-MOR. It was applied
UV-mediated photoreduction method which consists in reduction of Au3+
,
Pd2+
and Pt4+
and ions in presence of a low amount of TX-100 and under
UV-irradiation.
In order to obtain metal nanoparticles dispersed into channels
system of the H-MOR were used solutions of HAuCl4, PtCl4 and PdCl2
with constant concentrations (5·10-3
M). The solutions of metallic
precursors were mixed with a proper amount of TX-100. After stirring for
few minutes, the H-MOR was added in order to obtain a solid/liquid ratio
in order to obtain a loading by 1% (wt%). These mixtures were irradiated
for 3 hours by using a 12W Vilber-Lourmat UV-lamp. The solids were
separated by centrifugation and dried at 80°C for 8 hours. For bimetallic
nano-composites, we synthesized first the H-MOR loaded with gold seeds
by using a similar procedure. In these systems, TX-100 plays roles of both
reducing agent and particles stabilizer.
The sample properties have been studied employing powder X-
ray diffraction, DRS UV-VIS, FTIR, TEM and AFM methods. Powder X-ray
diffraction (XRD) patterns were collected on a BRUKER D8 Advance
Instrument using CuKα1 radiation (Ni λ= 0.15401nm, 40 kV and 50 mA).
TEM images were taken with a JEOL LEM-100CXII transmission electron
microscope at an accelerating voltage of 100 kV. The DRS UV-VIS
spectra were recorded on a Shimadzu UV 2401PC spectrophotometer
with an integrating diffuse reflective sphere and BaSO4 as reference, in
the range 200nm –600 nm.
Different states of ionic and metallic gold were detected in the
mordenite channels and on the external surface of the mordenite – Au+
and Au3+
ions, charged clusters Aunδ+
and neutral nanoparticles. The gold
loading in each mordenite sample was strongly related to the aluminium
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content; the gold species were reduced in the pores of the mordenite only
at lower temperatures.
Acknowledgments. The authors are grateful for the
MATNANTECH financial support, Project CEEX No.1/S1-2005.
References
1. Haruta, M., Size and Support Dependency in the Catalysis by Gold, Catalysis Today, 36 (1997), 153-162.
2. Galvagno, S., Parravano, G., Chemical reactivity of supported gold IV. Reduction of NO by H2, Journal of Catalysis, 55 (1978), 178-190.
3. Guillemot, D., Borovkov, V.Y., Kazansky, V.B., Polisset-Thfoin, M., Fraissard, J., Surface characterization of Au/HY by 129XeNMR and diffuse reflectance IR spectroscopy of adsorbed CO. Formation of electron-deficient gold particles inside HY cavities, Journal of the Chemical Soociety, Faraday Transaction, 93 (1997), 3587-3593.
4. Haruta, M., Yamada, N., Kobayashi, T., Ijima, S., Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide Journal of Catalysis, 115 (1989), 301-309.
5 Haruta, M., Tsubota, S., Kobayashi, T., Kageyama, H.,Genet, M.J, Delmon, B., Low- Temperature Oxidation of CO over Gold Supported on TiO2, α-Fe2O3, and Co3O4, Journal of Catalysis 144 (1993), 175-192.
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P-3-08. Mns Clusters into Zeolite Matrices
Felicia Iacomi1, Aurelia Vasile2, Eleni Pavlidou3,
E.K. Polychroniadis3 1 Faculty of Physics, “Al.I.Cuza” University, Iasi, Romania, [email protected] 2 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-
700506, Iasi, ROMANIA
3 Department of Physics, Aristotle University of Thessaloniki, Greece
Well defined MnS clusters were prepared within the pore structure
of natural zeolite matrix (clinoptilolite, laumontite and heulandite) by using
two procedures: aqueous ion exchange and impregnation followed by a
sulfidation process with H2S{1-3].
SEM examinations revealed that no disintegration of zeolite framework
had occurred during the synthesis. Optical absorption spectra evidenced
that impregnation method favors the formation of crystalline aggregates.
Optical spectra of MnS clusters formed by using the ion exchange method
are blue shifted and evidence bands at 276 nm and 233 nm. Some
emission spectra were studied as a function of temperature. The emission
band located at 410 nm was attributed to band-band transition of intra-
zeolite MnS cluster.
References
1. F. Iacomi, Surface Science, 532-535 (2003) 816. 2. F. Iacomi, A. Vasile, E.K. Polychroniadis, Material Science and
Eng. B101 (2003) 275. 3. F. Iacomi, M. Vasilescu, S. Simon, Surface Science 600 (2006)
4323.
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P-3-09. Synthesis and Characterization of SnO2 Nanoparticles Encapsulated in Zeolite Hosts
Aurelia Vasile, Carmen Mita
''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
Zeolites are the aluminosilicate members of the family of
microporous solids known as molecular sieves. This is due to a very
regular pore structure of molecular dimensions. The maximum size of the
molecular or ionic species that can enter the pores of a zeolite is
controlled by the diameters of the channels. Zeolites have diversified
areas of conventional application, including separation and adsorption
agent, shape selective solid catalyst, ion exchange agent,
chromatographic column filler, chemical reaction substrate, moisture
control agent, building materials.The nanosized channel system of the
zeolites provides a size- and shape-selective matrix for absorbed
molecules while maintaining a high surface-to-mass ratio. Molecules can
be organized within the framework with a high spatial precision on the
nanometer scale. In the area of optical materials, zeolites will be of
particular interest when specific distances or a spatial pattern of atomic,
ionic, molecular or nanoscaled quest species are required in order to
obtain the desired physical effects.
Synthesis and stabilization of semiconductor nanoparticles
encapsulated in different zeolite hosts has been studied for CdS, PbS, ZnS,
MnS, ZnO /1-6/. The methods for preparing of zeolite-entrapped nanoguests
are usually impregnation, ion exchange, heat dispersion, chemical vapour
deposition or direct synthesis. Synthesis of SnO2 zeolite-entrapped
nanoparticles by ion exchange from aqueous solution is not possible because
strong hydrolysis of Sn (IV) and complex cations formation.
This study presents the synthesis of zeolite-entrapped SnO2
nanoparticles by MSSIE method. The method allows incorporation of
SnO2 nanoparticles in zeolite hosts preventing the hydrolysis in the
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exchange slurry. Influence of zeolite structure type, SiO2/Al2O3 ratio (SR),
exchangeable cation, weight ratio (WR) and irradiation time on
incorporation of SnO2 nanoparticles was studied
Zeolites MOR and ZSM-5 were crystallized by hydrothermal
synthesis.The pure Na-forms were obtained by ion exchange from
aqueous solution of NaNO3 and H-form via NH4+
form. Tin tetrachloride
pentahydrate (SnCl4.5H2O) used was the reagent of analytical purity.
SnO2 nanoparticles semiconductor entrapped in zeolite hosts was
synthesized by the following procedure. The activated zeolite powder was
first mixed with SnCl4.5H2O at a given weight ratio and ground in a mortar.
The mixtures obtained were microwave irradiated using a non-modified
domestic oven (2450GHz, 700W) for 30 min. After heating, the samples
were washed with distilled water and ethanol, dried at 373K and calcined
at 573K for 3h. Zeolite samples used have high crystallinity and purity.
XRD, SEM, FTIR and DRS UV-VIS spectroscopy were used for
characterization of the prepared samples.
The XRD patterns show that after microwave irradiation the loss
crystallinity was not detected. Also, no crystalline SnO2 was detected in all
samples. DRS UV-VIS spectra of zeolite entrapped SnO2 show the
absence of the absorption band in the range 310~380 nm which is
attributed to crystalline SnO2. However, the absorption band in the range
250~270 nm was observed for all zeolite entrapped SnO2.The absorption
edge was determined as crossing point of the tangent through the point of
inflexion with the x-axis. For all the zeolite entrapped SnO2 samples the
absorption edge (in the range 250~270 nm) is significantly blue-shifted
compared to that of bulk SnO2 (358 nm). This blue- shift of the absorption
edge in comparison to bulk SnO2 indicates the presence of SnO2 very
small particles exhibiting quantum size effects. Zeolite structure type, SR,
exchangeable cation, WR and irradiation time influenced the properties of
the resulting samples. Na-zeolite is superior to H-zeolite and the lower
values of the SR lead to formation higher quantity of SnO2 nanoparticles in
zeolite hosts.
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SnO2 nanoparticles entrapped in zeolite hosts were prepared by
MSSIE method. The Sn (IV) can be effectively introduced into the
channels of zeolite hosts by MSSIE method avoiding the hydrolysis and
complex cations formation in the exchange slurry. The study showed that
microwave irradiation is a practical and simple technique and non-
modified domestic microwave ovens can be used as safe and convenient
laboratory devices.
References
1. Stucky, G. D., MacDougall, J. E., Science, 1990, 247, 669. 2. Wang, Y., Herron, N., J. Phys. Chem., 1991, 95,525. 3. A. Vasile, F. Iacomi, M. Caraman, Sci.Anal.”.Al.I.Cuza” Univ Iassy,
Physics. Plasma and Spectroscopy, tom XLVII, 2001, 157. 4. F.Iacomi A.Vasile,13
th IZC, Montpellier, France, 2001, Recent
Research Reprints 14-r-01. 5. F.Iacomi, A. Vasile, M. Caraman, Bul. Inst. Pol. Iaşi, tom XLVIII (LII)
fasc.1-2, 2002, 135 6. F.Iacomi, A.Vasile, E.K.Polychroniadis, Materials Science and
Engineering B101, 2003,275
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P-3-10. Some Studies on Natural Zeolite from Chilioara Area -
Romania
Eveline Popovicia, Maria Alexandroaeia, Aurelia Vasilea, N.Sulitanua, I.Calbb
a ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
b Exploatarea minieră Zalău
Natural zeolites – microporous crystalline aluminosilicates – have
found wide application in ion - exchange, adsorption/separation and
catalytic processes [1-3].
New discovered clinoptilolite deposits from Chilioara areal –
Romania represent a promising material for theoretical studies and
applications.
Samples from 5 zones of this areal were structural characterized
by X-ray diffraction, RES and FTIR analysis.
The Na-form samples -1, obtained by ultrasound assisted ion -
exchange with NaCl solution, were following subjected for ion-exchange
with Au3+
and Ag+ solution.
Special behavior was observed in the case of gold – clinoptilolite
samples: three types of gold species, inside the zeolite channels were
decelated: (a) Au3+
cations, (b) neutral onAu clusters and, (c) Au
nanoparticles located on the external surface of zeolite icrocrystals. Gold
nanoparticles were observed only as the result of reduction of the Au-
exchanged forms at elevated temperatures due to reduction of Au3+
species and aggregation of clusters.
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Figure 1. XRD patterns of samples 1-5 from Chilioara deposit.
The DRS spectra of all studied samples were observed. The
absorption band at 61500; 61472; 220 nm is assigned to the Au3+
ions
and the peaks with the maxim in the region 230 - 380 nm are supposed
to be attributed to the gold clusters [4].
In contrast, silver – clinoptilolite, after similar treatment, contains
only onAg clusters.
References
1. Horvath D., Polisset-Thfoin M. etc., Solid State Ionics, 2001, 141-142, 153.
2. Mohamed M., Ichikawa M., J. Colloid and Interface Science, 2000, 232, 381.
3. G. Riahi, D. Guillemot etc., Catalysis Today, 2002, 72, 115. 4. Y. Kang, B. Wan, Catalysis Today, 1997, 35, 379.
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P-3-11. Synthesis and Characterisation of Alumina Supported ETS-4
Pierantonio De Luca, Danilo Vuono, Alfonso Nastro. Department of Pianificazione Territoriale, University of Calabria, Via P. Bucci, I-87036, Arcavacata di Rende (CS), Italy. [email protected], phone-fax (+39) 0984 496783
In this paper we report on own results concerning the preparation
of ETS-4 supported on α-Al2O3. First, the pre-treatment conditions of the
support are optimised using a basic solution. Second, the best conditions
are searched for the deposition of the ETS-4 crystal.
The so-obtained materials are characterised by XRD, SEM, EDS
analysis, XR fluorescence. The adhesion strength of the crystals to the
support is checked by ultrasound bath, abrasion tests and thermal
treatment.
Keywords Molecular sieve, ETS-4, microporous.
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P- 4. MESOSTRUCTURED MATERIALS - SYNTHESIS AND MODIFICATION
P-4-01. Adsorptive Removal of Cationic and Anionic Dyes from
Aqueous Solutions on Si-MCM-41 Mesoporous Material
Camelia Luchian*, Iuliean Asaftei, Nicolae Bilba ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA *[email protected]
The discharge of coloured wastewater from textile and dyeing
paper, plastic, cosmetic leather and printing industries into natural water
bodies is currently a major environmental concern. Dyes in water affect
the nature of the water, impedes sunlight penetration into the stream and reduce
the photosynthetic reaction. Many dyes are toxic and even carcinogenic to some
organisms causing destruction of aquatic communities. The removal of colour
from dye-baring effluents is a major problem due to difficulty in treating such
wastewaters by conventional treatment methods (coagulation/flocculation, froth
flotation, reverse osmosis, chemical oxidation and adsorptive techniques).
Currently, the adsorption process provides an attractive viable and effective
alternative treatment due to its sludge free clean operation and completely
removed dyes. A large number of adsorbents have been used for the removal
studies of dyes: activated carbon, sepiolite, alunite, coal, fly ash, clayey soil, red
mud, perlite, zeolites, bagasse, rice husk, coir pith, peat, hardwood, chitosan.
In present work, the use of ordered mesoporous Si-MCM-41 as
adsorbent has been investigated as an ideal alternative for removal of
cationic (crystal violet, methylene blue, rhodamine B) and anionic dyes
(crysoidine, xylenol orange) from their aqueous solutions.
The Si-MCM-41 was synthesized by sol-gel method through a
hydrothermal route. The synthesis comprises alkaline hydrolysis of TEOS
in presence of C16TMAB as surfactant according to the modified reported
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procedure from one mixture with molar composition: 1.0TEOS:
0.2C16TMAB: 5.7NH4OH: 113 H2O.
The structure and the porosity of the calcined Si-MCM-41 sample
were characterized by XRD and N2 sorption. The highly ordered
hexagonally packed 1-D cylindrical pore was confirmed by the presence
of typical four-peaks, one, very strong at a low angle (d100 reflection lines)
and three weaker at a higher angle (d110, d200 and d210 reflection lines). N2
adsorption/desorption isotherm at 77 K is of type IV with a steep increase
at intermediate relative pressure (p/po) between 0.2 and 0.35, indicating
the capillary condensation related to the diameter of the mesopore. The
physical properties of Si-MCM-41 sample are: surface area, SBET=1200
m2.g
-1, pore volume, PV=0.83 cm
3.g
-1 and BJH pore size, DBJH=2.36 nm.
In order to evaluate the efficiency of Si-MCM-41 in adsorptive
removal of dyes from synthetic wastewaters, batch adsorption
experiments of cationic (CV, MB and RB) and anionic (CRI, XO) dyes
were achieved. The scope included the sorption isotherms, the initial dye
concentration and solution pH, temperature, contact time and adsorbent
dosage for all dyes. It was found that the percent of dye removed is
strongly depended on the solution pH, this affecting the surface charge of
the adsorbent. In the case of cationic dyes the adsorption increases when
pH was increased to 5.5-6 but in case of anionic dyes the maximum
adsorption is attained at pH = 1-2 after which decreases. For all studied
systems, percent of dye removal increases with the adsorbent dose and
temperature and decreases with increase of concentration of solution: the
required time for equilibrium establish is of maximum 1 hour. The
equilibrium adsorption data were analyzed using the sorption isotherms
models Freundlich and Langmuir.
Acknowledgments. This study was supported by the CEEX grant
No.1/S1/2005.
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P-4-02. Nanomaterials Based on Cyclodextrins Inclusion Compounds with Antioxidant Properties
C. Luca1, A.-M. Grigoriu1, B. Stoica2, A. Grigoriu3
1 „Gh.Asachi” Technical University, Iaşi, Faculty of Chemical Engineering
2 „Gr.T.Popa” University of Medicine and Pharmacy, Iaşi, Facultaty of Medicine 3 „Gh.Asachi” Technical University, Iaşi, Faculty of Textile and Leather Engineering
Cyclodextrins are substances which present nanocavities (with
the diameter in the range 0.57-0.97 nm) that include molecules of the
same size order (Fig. 1).
Fig. 1 The molecular structure and the schematical representation
of α-, β- and γ-CDs
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The term „antioxidant” refers to the capacity of molecules to
neutralize the so-called free radicals. Inclusion compounds of
β-cyclodextrin and of monochlorotriazinyl-β-cyclodextrin with different
guests with antioxidant properties (ascorbic acid, cinnamic derivatives –
ferulic acid, ethyl ferulate, caffeic acid) have been obtained. The inclusion
compounds have been prepared by crystallization from a mixture of a host
water solution and a guest alcoholic one. The products have been
characterized by ATR-FT-IR spectroscopy and chemiluminiscence. Both
the formation of the inclusion compounds and their antioxidant character
were emphasized. These compounds can find applications in the
cosmetically (toothpastes, creams, lotions, emulsions), pharmaceutical,
textile industries („wellness” textiles with an improved wearing comfort).
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P-4-03. Synthesis Characterization and Photocatalytic Activity of MCM-41 Containing ZnO Nanoparticles
G. D. Mihai1,2*, P. Cool1, N. Bilba2, E. F. Vansant1 1 University of Antwerpen, Laboratory of Adsorption and Catalysis,
Department of Chemistry, Universiteitsplein 1, B-2610 Wilrijk, Belgium; *E-mail: [email protected]
2 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
Due to its semiconductor properties, nanometer-sized ZnO has
attracted extensive attention as a photocatalyst for the degradation of
organic pollutants in water and air [1].
Mesoporous solids have received considerable attention in recent
years as host matrices for metal and semiconductor nanoparticles, which
may find important applications in photocatalysis and optoelectronic
devices. Due to its very high surface area and its narrow size pore
distribution, MCM-41 seems to be a good support material for ZnO
nanoparticles to be used as catalyst in potential applications in waste
water treatment and air purification. Methods that are based on the
impregnation of mesoporous silica matrices with zinc precursors have
become popular, but it is generally difficult to achieve high particle
loadings of the host matrix with this method. In this present investigation,
high ZnO particle loadings were prepared using MCM-41 support through
an impregnation method using non aqueous solution of organic salts [2].
X-ray powder diffraction, N2 sorption, EPMA and UV-vis spectroscopy are
used to characterize the ZnO-loaded MCM-41 materials. The influence of
the synthesis parameters on the pore characteristics and the
photocatalytic activity towards degradation of methylene blue in water
under the illumination of ultraviolet rays are investigated.
We have shown that the MCM-41 siliceous matrix can be loaded
by impregnation with Zn(ac)2 changing different parameters and some
structure modifications occur without the collapse of the porous
framework. XRD patterns confirm the existence of ZnO nanoparticles with
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hexagonal wurzite structure. Also, it was found that the ZnO loaded MCM-
41 exhibits high photocatalytic activity for degradation of methylene blue,
indicating that these materials are promising as semiconductor
photocatalysts.
Acknowledgments This study was supported by the NoE project
“Inside Pores” and the GOA project funded by the Special Fund for
Research of the University of Antwerp. This work is also part of the CEEX
No. 1/S1/2005 project.
References
1. M. D. Driessen, T. M. Miller, V. H. Grassian, J. Mol. Catal. A:
Chem. 131 (1998) 149. 2. Ying Xiong, Lei Z. Zhang, Guo-Qing Tang, Gui-Lan Zhang, Wen-
Ju Chen, J. Lumin 110 (2004), 17.
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P-4-04. Modification of Porous Supports for the Development of Hybrid Materials.
V. Meynen1,2, M. Özen1, A. Buekenhoudt2, P. Cool1, E.F. Vansant1
1 Laboratory of Adsorption and Catalysis, Department of Chemistry, University of Antwerpen, Campus Drie Eiken, Universiteitsplein 1, B-2610 Wilrijk, Belgium, email: [email protected]
2 Flemish Institute for Technological Research, VITO, Boeretang 200, B-2400 Mol, Belgium
Zeolites are the best known nanoporous materials with a wide
variety of applications in technology, industry and medicine. However, due
to their microporous nature (ø < 2 nm) large molecules and viscous liquids
are excluded from their porous network. Therefore, mesoporous
materials with large pore dimensions (2 < ø < 50 nm) are gaining
increasing interests due to their applicability in these type of processes
like in fine chemistry, biotechnology, biology, pharmacy. They create
accessibility for large molecules and the ability to allow and control high
mass transfers. Nevertheless, they are inferior to zeolites with regards to
stability, selectivity and activity.
Therefore, hybrid mesoporous materials are being developed in
order to create selectivity and stability which gives them more
opportunities in industrial applications.
Two main synthesis approaches can be applied for the creation of these
hybrid materials, which implement high selectivity and stability in
mesoporous materials. On one hand, mesoporous materials can be
impregnated with zeolitic nanoparticles creating materials with bimodal
porosity and unique porous characteristics.
On the other hand, mesoporous materials can be modified with
organic molecules which form functional and selective groups on the
surface of the carrier material (hybrid organic-inorganic materials).
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P-4-05. Mesoporous Carbons Obtained by Nanocasting Route
Maria Ignat, Eveline Popovici ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA [email protected]
Nanocasting, using highly ordered mesoporous silica as a
template, has brought forward large possibilities in preparing novel
mesostructured materials, like nanostructured carbons. These materials
with controllable pore size, high surface areas, and large pore volumes
have been greatly investigated in many fields of science and technology,
such as storage of hydrogen and methane, supercapacitor, molecular
separation, and catalysis [1].
The nanostructured carbons have been synthesized by various
methods e.g. electric arc discharge, laser evaporation and chemical vapor
deposition. Will be described a method to prepare mesoporous carbon by
using mesoporous silica with an interconnected pore system, type SBA-
15, as nanocasting molds.
The resulting porous carbon obtained after removal of the silica
mold by leaching is a negative replica of the host. The obtained carbon
materials can then be used as a mold for further replication to other metal
oxides, where the carbon is removed by combustion.
In the present work several nanostructured carbons were
synthesized by means of liquid impregnation of SBA-15 and
montmorillonite, as template, with sucrose – as reference – and polyol,
respectively. The precursors (sucrose or polyol) were converted to carbon
inside the mesopores of the silica molecular sieves through a mild
carbonization process using a sulfuric acid catalyst. The starting silica
monoliths were synthesized according to the procedure described by
Nakanishi [7].
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X-ray diffraction, nitrogen sorption, transmission electron
microscopy, atomic force microscopy and FTIR methods were used to
characterize the obtained nanostructured carbons.
The silica template allows a control of the pore morphology of the
obtained carbons. The nature of the carbon precursor influences the
characteristics of the obtained materials.
Keywords: nanocasting, hard template, mesoporous carbon
Reference
1 Ryoo, S. H. Joo, S. Jun, J. Phisical Chemistry B, 103, 37, 1999 2. M.S. Fuhrer, J. Nygard, L. Shih, M. Foreco, Y.G. Yoon, M.S.C.
Mazzoni, H.J. 3. Choi, J. Ihm, S.G. Louie, A. Zettl, P.L. McEuen, Science 288, 494
(2000) 4. A. Bachtold, P. Hadley, T. Nakanishi and C. Dekker, Science 294,
131 (2001) 5. R.H. Baughman, A.A. Zakhidov and W.A. de Heer, Science 297,
787 (2002) 6. A. Srivastava, O. N. Srivastava, S. Talapatra, R. Vajtai and P. M.
Ajayan Nature Materials; 3, 610 (2004) 7. K. Nakanishi, J. Porous Mater., 1997, 4, 67. 8. K. Jurewiczb, C. Vix-Guterla, E. Frackowiak, Journal of Physics
and Chemistry of Solids 65 (2004) 287–293 9. Smalley et al., 7125534, Catalytic growth of single- and double-
wall carbon nanotubes, Oct. 24, 2006 10. M. Monthioux, H. Allouche, R. Jacobsen, Chemical vapour
deposition of pyrolytic carbon on carbon nanotubes, Carbon 44 (2006) 3183–3194
11. John C. Hulteen, Charles R. Martin, A general template-based method for the preparation of nanomaterials, J. Mater. Chem., 1997, 7(7), 1075–1087
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P-4-06. Synthesis of Nanostructured Carbons by Solid Waste Valorization
Maria Ignat, Eveline Popovici ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA [email protected]
The controlled assembly of nanoparticles has been proposed as
one of the most promising ways to achieve the targets of Nanotechnology.
Once we are capable of such control, the creation of components and
devices which can exploit the fascinating, size-dependent properties of
nanomaterials will be possible.
Carbon nanotubes (CNT), both SWNT and MWNT, are unique
nanostructures with remarkable electronic and mechanical properties and
could be used as key components in the production of high-strength
composites, and advanced sensors, electronic and optical devices,
catalysts, batteries and fuel cells.
Conventionally, carbon nanotubes have been manufactured by a
physical method, such as discharging or laser vaporization, or by a
chemical method such as chemical vapor deposition.
We present a simple, generally applicable procedure for the
assembly of nanoparticles on carbon nanotubes in aqueous solution. This
method for manufacturing carbon nanotubes using waste binding carbon
nanoparticles (pitch) resulted in house ovens, based on coal [1]. Binding
carbon nanoparticles (pitch) are dispersed in a strong acid solution and
heated at 130º C , under reflux, followed by its transformation into carbon
nanotube. By this method, a solid waste was transformed into a
mesoporous nanostructured materials. It was realized a valorization of
solid waste by its transformation into carbon nanotubes.
X-ray diffraction, nitrogen sorption BET, Transmission electron
microscopy, Atomic force microscopy, FTIR were used to characterize the
obtained nanostructured carbons.
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Keywords: carbon nanoparticles, pitch, valorization.
Reference
1. Patent USA 7078007 Yu et al., Jul. 18, 2006. 2. R.K Gupta and I. Dwivedy, Current Applied Physics, Volume 5,
Issue 2 , 2005, Pages 163-170. 3. Y. Cheng, J. Gerald, L. Chadeerton et al., Nanoporous carbon
produces by ball milling, Apl. Ph. Letters, V 74, 1999. 4. S. Iijima, helical microtubules of graphitic carbon, Nature 354, 56-
58 5. Erik Oscar Sunden, Carbon nanotube synthesis for microsystems
applications, Georgia Institute of Technology, august 2006. 6. K. Elias, R. Price, T. Webster, Enhanced functions of osteoblasts
on nanometer diameter carbon fibers, Biomaterials, vol. 23, p. 3279-3287, 2002.
7. H.Hu, Y. Ni, V. Montana, R. Haddon, V. Parpura, Chemzcalyz functionalized carbon naotubes as substrates for neuronal growth, Nano Letters, vol.4, p. 507-511, 2004.
8. V..Lovat, D. Pantarotto, L. Lagostena, B. Cacciari, M. Grandolfo, M. Righi, G. Spalluto, M. Prato, L. Ballerini, Carbon nanotube substrate bosst neuronal electrical signaling, Nano Letters, vol.5, p. 1107-1110, 2005.
9. J. Charest, L. Bryant, A. Garcia, W. King, Hot embossing for micropatterned cell substrates, Biomaterials, vol.25, 4767-4775, 2004.
10. M. Savopulo, B. E. Burakov, Development, Fabrication and Study of Fullerene-Containing Carbon Material (FCC) for Immobilization of Iodine, Saint-Petersburg - 2004
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P – 4-07.Study of Grafted Layer of Mesoporous Alumina Modified with Alkylphosphonic Esters by Spin Label Technique
P.E.Burtseva, P.G.Mingalev, G.V.Lisichkin Moscow State University, Chemistry Department Moscow, Russia, [email protected]
Phosphonic esters are new, promising type of modifiers for the
surfaces of various oxides, such as oxides of aluminum, iron, copper etc.
At the same time, in order to make the samples of modified oxide with
predictable properties, one should have a clear knowledge of the structure
of the grafted layer and of the factors, which can have influence on this
structure.
Spin label technique is a convenient and powerful method for the
investigation of the grafted layer structure. We used it to study the grafted
layer structure of mesoporous alumina, modified with esters of various
phosphonic acids. It was shown that these esters can give a dense
monolayer, which, however, have some defects. As was found,
submonolayers of grafted phosphonic groups have a pronounced island-
like character, and these islands merge as the surface density value is
increased.
It was also shown that the increase of the modifier concentration
and the temperature of reaction results in the increase of the surface
density value.
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P-4-08. Carbon Nanotubes Decorated with Fe, Co, Zn Nanoparticles
Maria Ignat 1, P.Barvinschi2 , Eveline Popovici1, A. Nastro3
1 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA, [email protected]. 2 West University of Timisoara, Faculty of Physics, Bvd. V.Parvan
4, 300223, Timisoara, Romania 3 University of Calabria, Department of Pianificazione Territoriale, Via P. Bucci, 87036 Arcavacata di Rende (CS), Italy.
In recent years, carbon nanotubes (CNTs ) have received a great
deal of attention due to their special physico-chemical, mechanical and
electronic properties [1–3].
By decoration with the catalytically active metal nanoparticles,
impregnated in pores volume or attached to the external walls [4-8], the
carbon nanotubes bring new possibilities of uses in catalysis. The
electronic properties of CNTs have stimulated many applications as
conductors or semiconductors and in the magnetic data storage media.
The results of this research are based on a rapid, convenient and
environmentally benign method for the fabrication of metal nanoparticle–
multiwall carbon nanotube (MWCNT) composites. Functionalized carbon
nanotubes it was prepared by impregnation of CNTs with Fe, Co, Zn, organic
aqueous solutions as metal precursors. Metal nanoparticles were synthesized
by decomposition of metal organic compounds inside CNTs pores.
X-ray diffraction, Raman spectroscopy, Transmission Electron
Microscopy, FT-IR spectroscopy was used to characterize the obtained
metals nanoparticles coated with carbon nanotubes.
Keywords: carbon nanotubes, metal nanoparticles, functionalization.
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References
1. P. M. Ajayan, Chem. Rev., 1999, 99, 1787. 2. J. Hu, T. W. Odom and C. M. Lieber, Acc. Chem. Res., 1999, 32, 435. 3. E. W. Wong, P. E. Sheehan and C. M. Lieber, Science, 1997, 277, 1971. 4. X. R. Ye, Y. Lin and C. M. Wai, Chem. Commun., 2003, 642. 5. Z. L. Liu, X. H. Lin, J. Y. Lee, W. D. Zhang, M. Han, L. M. Gan,
Langmuir, 2002, 18, 4054. 6. B. Xue, P. Chen, Q. Hong, J. Lin and K. L. Tan, J. Mater. Chem.,
2001, 11, 2378. 7. V. Lordi, N. Yao and J. Wei, Chem. Mater., 2001, 13, 733. 8. X.R. Ye, Y. Lin, C. Wang, M. H. Engelhard, Y. Wanga, C. M. Wai,
J. Mater. Chem. , 2004 , 14 , 908 – 913
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P-5. CATIONIC AND ANIONIC CLAYS
P-5-01. Removal of Cr (VI) from Wastewater by Sorption on Isomorphic Substituted Mg/Zn-Al - Type Hydrotalcites
Laura Cocheci1, Rodica Pode1, Eveline Popovici2, Elena Seftel2, Emiliana Dvininov2 1 “Politechnica” University, Timisoara, 300006, Romania
[email protected] 2 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
Chromium (VI) is generally produced via industrial processes
(electroplating, mining, tanning and synthetic fertilisers) and it is
commonly found at contamination sites. Exposure to Cr(VI) may increase
one’s risk of contracting cancer or developing hypersensitivity of the skin
or respiratory system. Moreover, because Cr (VI) exhibits high mobility in
most neutral and alkaline soils, it poses a great threat to surface and
groundwater. Therefore, it is necessary to eliminate Cr (VI) from the
environment.
Layered double hydroxides (LDHs) or hydrotalicite-like
compounds exhibit properties such as anionic mobility and surface
basicity, and they are effective sorbents for the removal of oxoanions,
heavy metals as oxometallate anions and cations and organic pollutants.
The chemical composition of the LDHs can be described by the formula
[M2+
1-xM3+
x (OH)2]x+
[An-
x/n . mH2O]
x-, short denoted [M
2+R - M
3+ - A], where
M2+
and M3+
are metal cations, An-
is an exchangeable anion, and R is the
molar ratio M2+
/M3+
. The decomposition of LDHs when heated at around
500°C leads to mixed metal oxides, which are characterized by high
specific surface areas and homogeneous dispersion of metal cations.
The aim of this study was to investigate the role of a second
bivalent cation intercalation (isomorphic substitution) in the LDHs structure
on the sorption of Cr (VI).
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The sorption experiments used the mixed oxides obtained after
calcination of Mg/Zn-Al - type hydrotalcites, where Mg/Zn = 3; 2; 1; 0. All
experiments were conducted batch wise, at 20±2°C, in an orbital shaker
model GFL 3017.
The aim of the equilibrium experiments was to establish the
optimum conditions (LDHs concentration and granulation, mixing rate) of
the sorption process, and to determine the maximum sorption capacities
of the mixed oxides for the Cr (VI) removal. The calcined LDHs were able
to remove more than 50% of Cr (VI) anionic species within a wide range
of concentration.
The data from the kinetic experiments were processed based on
Lagergren equation and the results fitted satisfactory.
Acknowledgments. The results are obtained as part of the
Project CEEX No. 1/S1 – 2005 activities, under the auspices of
MATNANTECH Scientific Authority.
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P-5-02. Preparation and Characterization of nano SnO2 –Cationic Clays
Aurelia Vasile, Eveline Popovici, Claudia Hristodor
''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA
In the last year’s metal-clays, aluminosilicates with properties and
characteristics of microporous materials have received more attention, as
the possibility of their use as matrix for encapsulation and stabilization of
the nanoparticles. The recognized importance of size quantized
semiconductor particles has prompted their extensive investigations and
the appearance of an ever increasing number of publications. Tin dioxide,
a material with versatile applicability in a large number of physicochemical
procedures, is one of the most intensively studied semiconductors. As an
n-type semiconductor, it is extremely sensitive to reducing gases (CO, H2,
ethanol, hydrocarbons) and may therefore be made use of as a gas
sensor.
This study was focused on the synthesis of nano SnO2 by in situ
between the lamellae clay synthesis, the conventional impregnation
method and the original modified impregnation method followed by
calcination or microwave irradiation. Influence of tin content of the
impregnation solution, surfactant content of the modified sodium-
montmorillonite, temperature and duration of the calcination on in situ
SnO2 nanoparticles formation was studied. The tin oxide content of nano
SnO2-montmorillonite varied between 15 and 40 wt%.
The starting material Romanian industrial montmorillonite, fraction
of size between 0.060 and 0.125 mm, from Valea Chioarului area was
used as starting material. The clay was firstly purified and homoionized by
ionic exchange with NaCl solution. The clay had the following composition
(% wt): SiO2-72.87; Al2O3-14.5; MgO-2.15; Fe2O3-1.13; Na2O-0.60; K2O-
0.60; CaO-0.90; PC-5.70. The clay mineralogical composition consists of
kaolinite (K), illite (I), montmorillonite (M) and nontronite (N), besides small
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quantities of feldspar–albite (F) and quartz (Q). The cationic exchange
capacity (CEC) value of the Na-clay was found to be 82 meq/100g
(determined by ammonium acetate method). The specific surface area of
98m2g
-1 was measured using the methylene blue adsorption method.
Also, a surfactant modified Na – montmorillonite with CTAB was prepared
and used as starting material. The nano SnO2-montmorillonite were
prepared in the following way: a 1% Na-montmorillonite or surfactant
modified Na – montmorillonite suspension was added different amount of
SnCl4.5H2O (as tin precursor) with constant stirring (magnetic stirrer);
stirring was continued for 1 day for ion exchange processes to be
completed. Then, solution of 0.5 M NaOH was added drop wise.
Formation of tin oxide nanoparticles between the lamellae of the
clay or surfactant modified clay was verified by X-ray diffraction (BRUKER
D8 Advance instrument using CuKα1 radiation; Ni filter, λ = 0.15401nm, 40
kV and 50 mA), diffuse reflectance DR-UV/Vis (Shimadzu UV 2401PC
spectrophotometer with a integrating diffuse reflective sphere and BaSO4
as reference), FT-Raman (Nicolet Nexus FT-Raman spectrometer) and
gas adsorption (BET) technique. The photocatalytic activity of the
obtained nano SnO2 - montmorillonite samples was investigated by
degradation of salicylic acid. XRD measurements indicated the sizes of tin
oxide particles to be in the 2-6nm diameter range between the layers of
clay. The distinct blue-shift of absorption edges in DR-UV/Vis spectra
point to a decrease of the particles size in comparison to the bulk material.
It was established that the sizes of the SnO2 nanoparticles depend
strongly on the preparation method. Also, the size of the SnO2
nanoparticles is correlated with the photocatalytic activity of the obtained
nano SnO2 - montmorillonite samples. Due to the smaller sizes of the tin
oxide species obtained, the surfactant modified sodium-montmorillonite
appears to be the most promising matrix for hostage of tin oxide
nanoparticles. It was established that the photocatalytic activity of the
nano SnO2 - montmorillonite prepared is mainly due to presence of
nanosized tin oxide particles. By selecting the appropriate experimental
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conditions, was accomplished size-controlled synthesis of nanoSnO2 -
montmorillonite. In the case of the surfactant modified Na–montmorillonite
with 0.14 mmol CTAB/g, the spectra showed the absorption centred on
315-318 nm, 230-233nm.The observed blue-shift of absorption edges in
DR-UV/Vis spectra point to a decrease of the particles size in comparison
to the bulk material. The similar behaviour was observed and in the case
of samples prepared with 0.05 mmol CTAB/g. The surfactant modified
sodium-montmorillonite appears to be the most promising matrix for
hostage of tin oxide nanoparticles.
Acknowledgments. The authors are grateful for the
MATNANTECH financial support, Project CEEX No.1/S1/2005.
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P-5-03. TiO2-Pillared Montmorillonitic Clay for Sustainable Development
Evelini Popovici1, Rodica Pode2, Aurelia Vasile1, Vasile Pode2, Laura Cocheci2 1 ''Al.I.Cuza'' University, Faculty of Chemistry, 11 Carol I Blvd., R-700506, Iasi, ROMANIA, [email protected] 2 University “Politehnica” Timisoara, Faculty of Industrial
Chemistry and Chemical Engineering, Victoriei Sq. No.2, 300006 Timisoara, Romania
Reports within the last years pointed towards the presence of new
xenobiotic substances in the environment as a consequence of massive
utilization of chemicals for various manufacturing purposes and in day-by-
day life. The incapacity of the conventional wastewater treatment
techniques to fully eliminate most of the biorefractory pollutants has
increased the environmental awareness with respect to set up and
development of more effective treatment systems (FORANO, 2004). A
strong carcinogenic potential was ascribed to azoic dyes and their
degradation products. In addition, they contribute to eutrophication and
disturbance of aquatic ecosystems.
This paper studied the sorption and photodegradation of Congo red
on TiO2-pillared montmorillonite and TiO2-pillared montmo- rillonite
modified by surfactant intercalation. The main goals were equilibrium and
kinetics of photocatalysis, and identification of the appropriate theoretical
models (SAFA OZCAN et al., 2005, GUETTAI & AIT AMAR, 2005). The
equilibrium data interpreted by using the Langmuir model allowed the
determination of the specific thermodynamic constants and identification
of the process as a physical sorption. The Langmuir – Hinshelwood model
was the base for interpreting kinetic data and working out of the rate
constant and reaction order. Under the conditions of the adsorbent
excess, from the kinetics point of view, an apparent first-order model can
be assumed and the pseudo-first-order rate constant was determined
(k’=3.85·10-1 min-1). Also was finding that, under well determined
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conditions, the efficiency of the photocatalysis was double as compared to
sorption.
The study highlighted the role of photocatalysis as part of the dye
removal process. Given the working conditions (Congo Red
concentration: 20 mg L-1 and adsorbent concentration: 0.4 g L-1), the
photocatalysis practically determined double Congo Red removal
efficiency on Ti-PILC as compared to the simple adsorption of the dye.
The experiments carried out on montmorillonite-monocationic form, TiO2-
pillared montmorillonite and TiO2-pillared montmorillonite modified by
surfactant intercalation showed that pillaring increased the dye removal
yield and intercalation enhanced the process. Clay samples incorporating
various concentrations of cetyltrimethylammonium bromide (CTAB) were
synthesized to determine the optimum concentration of surfactant. To get
data concerning the optimum surfactant concentration required to modify
the clay to increase efficiency, three clay samples were studied for
surfactant intercalation by using various surfactant concentrations and the
results were compared to the pillared clay. After ten minutes contact time,
the dye removal efficiency increased from 25.4% in the presence pillared
clay (Ti-C) to 42.7% in the presence of 0.059 g surfactant /g clay. After the
same time interval, the dye removal efficiencies on S2-Ti-PILC and S3-Ti-
PILC samples were similar, which concluded that a concentration of 0.29
g surfactant/g clay was not justified. The intercalation of the surfactant
within clay lattice was reasonable up to 0.29 g surfactant/g clay. For the
same duration, the increase of the photocatalytic material concentration,
i.e., increase of catalytic surface area, led to the increase of removal
efficiency.
Based on results, beyond a certain CTAB concentration the
positive effect of surfactant was not noticed.
Acknowledgments. The authors are grateful for the
MATNANTECH financial support, Project CEEX No.1/S1/2005.
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References
1. FORANO, C. (2004): Environmental Remediation involving
Layered Double Hydroxides.– In: WYPYCH, F. & SATYANARARAYANA K. G. (eds.): Clay Surfaces. – Elsevier, London, 425 p.
2. GUETTAI, N. & AIT AMAR, H. (2005): Photocatalytic oxidation of methyl orange in presence of titanium dioxide in aqueous suspensions. – Desalination, 185, 439-448.
3. SAFA OZCAN, A., ERDEM, B. & OZCAN, A. (2005): Adsorption of Acid Blue193 from aqueous solutions onto BTMA - bentonite. - Colloid Surface A, 266, 73-81.
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P-6. INDUSTRIAL AND ENVIRONMENTAL APPLICATIONS
P-6-01. Removal of Copper (II) Ions from Aqua Solutions by Adsorption on Poplar Sawdust
Corneliu Cojocaru *, Mariana Diaconu, Matei Macoveanu, Igor Cretescu Department of Environmental Engineering and Management, Technical University of Iasi Bvd. D. Mangeron 67, 700050 Iasi, Romania [email protected]
The applying of natural organic materials as low-cost adsorbents
for the removal of heavy metals ions from wastewater is an actual trend in
environmental protection science and technology. Locally available
sawdust of Populus sp is a waste material derived from the commercial
processing of poplar wood. This type of sawdust was found to be a low-
cost adsorbent promising for the removal of copper (II) ions from aqua
solutions and wastewater. In the present work, the ability of poplar
sawdust to remove Cu (II) ions from aqueous solution has been
investigated. In this respect the batch techniques were employed. The
equilibrium adsorption level was determined to be a function of the
solution pH, initial Cu(II) concentration and temperature. Freundlich,
Langmuir, Redlich-Peterson and Sips isotherm have described the
equilibrium adsorption capacity of poplar sawdust for copper. In addition,
the equilibrium nature of copper (II) adsorption at different temperature
(20-50C) has been investigated. The thermodynamic parameters like
free energy and enthalpy changes for adsorption of Cu(II) by poplar
sawdust have been computed and discussed.
Also the poplar sawdust has been employed in the studies
concerning the optimization of sorption removal efficiency of copper from
aqua solutions. The prior investigations indicated that the initial pH of
solution, initial concentration of Cu(II) ions and the sorbent dose are the
most important factors that affect the sorption removal efficiency.
Therefore, the present paper discusses also the experimental design and
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response surface methodology (RSM) as an efficient approach for
predictive model building and optimization of removal efficiency using the
sawdust of Populus sp as inexpensive sorbent. All experiments were
statistical planned according to central composite experimental design
(CCD) of orthogonal type. Based on experimental design the response
surface model was developed and the optimization of factors was
accomplished in order to ensure high sorption removal efficiency. The
developed response model has been validated from statistical standpoint
to ensure the goodness-of-fit. Likewise, the 3D plots and contour-line plots
were drawn for spatial representation and analysis of the response
surface.
P-6-02. The Use the Zeolite Molecular Sieves for CO2 Capture
from Exhaust Gases of Power Plants
Aurelia Bolma1, Dorin Bombos2, Gheorghe Bumbac3, Fanica Bacalum4, Rodica Ganea5, Marcela Pitu5, Mihaela Bombos4, Agnes Serbanescu1 1 ICEMENERG S.A, 8 Energeticienilor Blvd. Bucharest 3, Romania
2University Gas & Oil Ploiesti, 39 Bucuresti Bldv., Ploiesti, Romania,
3 University Politehnica Bucuresti, CTTIP, Polizu #1, Bucharest 6, Romania
4 INCD - ICECHIM, 202 Independentei Blvd. , Bucharest 6, Romania
5 ZECASIN S.A., 202 Independentei Blvd. , Bucharest 6, Romania [email protected]
The global pollution produced by the greenhouse gases represents now
one of the most complex problems of global environmental protection. The
greenhouse gases (GES) participate in the modification of the
atmospheric strata, having direct consequences on the Earth’s
temperature, process known as “global warming” or, of late, as “global
climatic change”. The GES specified in the Kyoto International Agreement
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are: carbon dioxide, methane, nitrogen oxide, hydrofluorocarbons,
perfluorocarbons, sulphur hexafluoride.
This paper presents a modern post-burning technology for capturing the
green house effect gases produced of power plants in the adsorbant
structure, such as zeolite molecular sieves. The process operates on a
repeated cycle with the basic steps being adsorption and regeneration. In
the adsorption step, gas is fed to a bed of solids that adsorbs CO2 and
allows the other gases to pass through. When a bed becomes fully loaded
with CO2 the feed gas is switched to another clean adsorption bed and
the fully loaded bed is regenerated to remove the CO2. In pressure swing
adsorption (PSA), the adsorbent is regenerated by reducing pressure.
The paper also presents the characterization of the composition of
burning gases resulted from energetic industry and the adsorbants
synthesis. The adsorbant structure was synthetised so that the adsorption
process should present a high selectivity for the component which is to be
removed. In achieving this process, the main role is played by the
physical-chemical characteristics of the adsorbant: specific surface,
volume of pores and medium pore radius, which must approach the
molecular dimensions (micropores).
Index Terms: burning gases, CO2 , post-burning technology, zeolite
molecular sieves, physical-chemical characteristics of the adsorbant.
References
1. H. J. Maldonado and R. T. Yang, Industrial Engineering Chemistry
Research, 42, 2003, 3103
2. Khelifa, Z. Derriche, 13th International Zeolite Conference,
Montpellier, France, July 8-13, 2001, 17-P-14
3. E. Munoz, E. Diaz, S. Ordonez and A. Vega, Annual Meeting: Environmental Applications of Adsorption, 2006
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P-6-03. The Role Played by the Convergent Technologies in Accomplishing Textile Structures
Carpus Eftalea, Dorogan Angela, Scarlat Razvan - The Research – Development National Institute for Textile and Leather [email protected] Ignat Mircea - The National Institute for Electrical Engineering Research – Advanced Research
New materials, nanotechnologies and production processes are
among the most attractive research areas and they remain a mystery for
the public. At the beginning of the 3rd
millennium, humanity is at a
crossroad. The fascination offered by the recorded achievements in
physics, chemistry, biology, medicine and engineering led to new
technological approaches having an overwhelming economic – social
impact. There occurred a shift in the consumers’ values: instead of
wishing for the finest natural materials, people look at beauty through
engineering, innovative design and the intelligent aspect of products.
The scientists, engineers and political factors of the convergent
technologies sketched general domains in which there will probably result
human benefits and social problems:
� the assembly potential of the convergent technologies;
� the extending of human knowledge and contact;
� the improving of human health and physical capacities;
� the improving of the social and group results;
� the national security;
� the unifying of science and education;
The need of convergence in textiles is defined by the following
requirements: the garment as a universal interface; the miniaturization of
technologies; the satisfying of the customers’ needs; the improving of life
quality; textiles as the third dimension of intelligence. The
nanotechnology, biotechnology, information technology and cognitive
science convergence under the generic title “Convergent technologies for
improving human performance” implies human creativity and innovative
ideas aiming at accomplishing personalized, adaptable, synchronized -
with - people textiles that are used in information processing at any
moment, in any place and for anybody.
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P-6-04. The Pb (II) Sorption from Aqueous Solutions by Sphagnum Moss Peat
L.Bulgariu, B. Robu, M. Macoveanu Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering and Management, D. Mangeron 71 A, 700050 Iasi, Romania Phone/fax: 00 40 232 271 759, email: [email protected]
The lead is a biological poison; it has a high toxicity and could
bring out the obstruction of human nervous central system. Due of the fact
that there are so many industrial sources of lead pollution; there is a high
interest of his removal from industrial wastewaters. The actual interest is
to remove toxic metals such as lead from wastewaters using very
economical materials and very accessible experimental procedures.
The sorption of lead from aqueous solutions by Sphagnum moss
peat from Poiana Stampei, Romania has been studied as a function of
several experimental parameters. The aqueous solution influence of
various pH, also the initial metal concentration, peat dose and contact
time were studied in batch experiment, for three types of peat. The
Sphagnum moss peat was collected from different deeps such as 5 cm
deep, 1 m deep and from 3 m deep. For each experiment was used the
natural peat as collected from site Poiana Stampei, Romania, and the
activated peat with solutions of NaOH and H2SO4 1N.
For natural peat analysed, the sorption percent of lead has a
maximum value (99.3%) when the solution has a pH = 6.0, and is still
increasing with the increase of peat dose. The maximum concentration of
lead that can be removed is 33.2 mg Pb/g peat, and it is considerable
higher than the actual values from literature. Concordant to literature the
activated peat has more efficiency for lead adsorption, so that the
Sphagnum moss peat can successful used for removal of lead ions from
wastewaters.
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P-6-05. Basic Investigation on Phase Behavior of Hydrogenated Castor Oil and Possible Applications in Encapsulation Using PGSS Technique
Lucian Hanu, Sabine Kareth, Eckhard Weidner Chair for Process technology, Ruhr-Universität, Bochum, Germany, e-mail: [email protected]
Hydrogenated Castor Oil can be used as an additive for
formulations or encapsulation for food and pharmaceutical industry.
Additionally, hydrogenated Castor oil can be designed with tailor-made
morphologies and sizes by supercritical spray processes.
For these processes, the need of knowledge about phase behavior and
fluid dynamic properties in presence of supercritical fluids is evident.
Phase behavior analyses were performed to see the influence of
temperature and pressure (induced by CO2) on physical properties of
the fat. The solubility of CO2 in the fat, the viscosity and density of
CO2 saturated fat were measured. It was of special interest whether a
decrease of the melting point of hydrogenated Castor oil with
increasing pressure would occur. The dissolved gas causes a
decrease in the melting temperature.
High pressure technologies like PGSS (Particles from Gas
Saturated Solutions) allow generating powders with properties which are
difficult to achieve by classical methods like milling, crystallization or
spray drying [1]. A very promising possibility is to use PGSS process to
obtain filled micro particles, solid - solid or solid – liquid composites [2].
Encapsulation of sensitive substances can form an effective protection
against stress factors. The objective is not only the protection of the
sensitive substances, but additionally the micro encapsulation opens
new possibilities for the control of the release of the active substances.
Using a matrix like hydrogenated Castor oil the aim is to generate
particles with the active substance (e.g. a natural plant extract)
encapsulated.
References
1. E. Weidner, Proc. 6th International symposium on supercritical
fluids, Versailles, (2003), 1483– 1495;
2. G. Brandin, Herstellung pulverförmiger Komposite mittels Hochdrucksprühverfahren, Dissertation Bochum, 2005.
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P-6- 06. Ecological Pesticides Based on Layered Double Hydroxides Nanocomposite
Mihaela Frunza, Ionel Marcel Popa Technical University, Iasi, Romania, [email protected]
Pesticides are nowadays widely used in modern agriculture. Only
a small quantity of the applied pesticide is bioactive while a high quantity
is released in the environment (e.g. migrating on or in the soil and
groundwaters, being volatilized in air or being photocatalytically
degraded). The high amount of the used pesticides gives rise not only to
environmental problems but also can affect our health.
Layered double hydroxides (LDHs) represented by the empirical formula
[M(II)1-x M(III)x ·(OH)2]x+
(An-
)·mH2O are a class of ionic lamellar solids with
positively charged layers, counterbalanced by exchangeable interlayer
anions. The large variety of anions that can be incorporated in the brucite-
like layer and the high anionic exchange capacity of these materials allow
using them as matrices for tailoring specific organic – clay hybrid
structures with new potential applications.[1-3]
The incorporation of the organic pesticides in the structure of
layered double hydroxides (LDH) can offer premises to increase the
pesticide active life by reducing its volatilization, controlling the release of
the pesticide from the layered structure and decreasing the pesticide
adsorption in soil and groundwaters.
We want to report in this work the synthesis and characterisation
of layered double hydroxides intercalated with some pesticide (4,6-dinitro-
o-cresol, 2,6-dichlorobenzonitril and 2,4-dichlorophenoxyacetic acid).
References 1. Carja G., Frunza M., Popa M.I. and Popescu C., 2005: The
Polytechnic Institute Bulletin, Iaşi, Tomul LI (LV), Fasc. 1. 2. Hussein M. Z., Long C. W., 2004: Materials Chemistry and Physics,
85, p.427-431. 3. Van der Ven L., Van Gemert M. L. M., Batenburg L. F, Gielgens J.J.,
2000: Appl. Clay Sci., 17, p.25-34.
Acknowledgements: This work has been supported by Ministry
of Education and Research Romania, by CNCSIS cod 53/2006.
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P-7. OTHER ASPECTS OF NANOMATERIALS SCIENCE AND TECHNOLOGY
P-7-01. Small Angle Neutron Scattering from Ferrofluids in
Magnetic Elastomers
E.M. Anitas1, C. Muresan1, M. Balasoiu1, A.I. Kuklin1, I. Bica2 1 Joint Institute for Nuclear Research, Dubna, Moscow
region, Russian Federation. 2 The West University of Timisoara, Timisoara, Timis County,
Romania. Email address: [email protected]
We report small angle neutron scattering (SANS) from ferrofluids
in magnetic elastomers. SANS method is a powerful technique for
studying the microstructure of ferrofluids (magnetic liquids) under different
conditions and is based on the interaction of thermal neutrons with atoms
of the studied medium. Neutrons are charactarised by a large penetration
depth, which makes it possible to study the unmodified bulk samples.
Fig.1. Experimental data (points) and the theoretical model (curve) of non-interacting polydisperse core-shell particles
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SANS was applied for determining the structure of colloidal
suspensions of a magnetic liquid embedded in a composite material. The
mathematical model founded, which fits experimental data well, see Fig.
1, and is of non-interacting polydisperse core-shell particles. The
magnetic liquid consists of magnetic particles and oleic acid in mineral oil.
The composite material is a polymer matrix of stomaflex crème.
Keywords: Ferrofluids, small angle neutron scattering, magnetic
elastomers, stomaflex crème, oleic acid
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P-7-02. Investigations on the Micronisation of Cacao Butter by the PGSS Process
L.Gontaru, S.Kareth, M. Petermann, M., E.Weidner Chair for Process Technology – Faculty of Mechanical Engineering, Ruhr-University Bochum, Universitätstr.150, 44780 – Bochum, Germany. Contact E-mail: [email protected]
High pressure technologies allow to generate powders with tailor
made properties (like: size, size distribution, morphology, crystalinity) that
are difficult or even impossible to achieve by classical methods like
milling, crystallization, spray drying or agglomeration. One of these
technologies is the PGSS process (Particles from Gas Saturated
Solutions) which offers the possibility not only to generate particles from
pure substances, but can also be applied for the formation of composites.
This process runs at low temperatures with pressurized carbon dioxide
and is suitable for products that are sensitive to heat or oxidation. The use
of organic solvents, emulsifying agents or other additives can be avoided.
For these reasons the PGSS process operates at especially gentle
conditions and is environmentally compliant. The possibilities of the PGSS
process have successfully been demonstrated over the last years for
numerous substances. Solid as well as liquid substances are transferred
into a form, which is easy to be dosed and admixed. One of the
applications for the PGSS process is to obtain powderous cocoa butter in
form V. Six polymorphic forms of cocoa butter are known. However, only
form V shows the optimal melting behavior for cocoa butter in chocolate.
Recently it was demonstrated, that the PGSS technology is suitable for
generating fluid-filled particles for food applications (e.g. powderous
chocolate encapsulated with liqueur).
Keywords: PGSS, Particles from Gas Saturated Solutions, high pressure,
food products.
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P-7-03. Magnetic Field Effect upon Bioactive Substances
Adsorption
Loredana Elena Nita1, Aurica Chiriac1, Sossio Cimmino2, Clara Silvestre2, Donatella Duraccio 2 1 “Petru Poni” Institute of Macromolecular Chemistry
Grigore Ghica Voda Alley no. 41A, 700487 Iasi, [email protected] 2 Istituto di Chimica e Tecnologia dei Polimeri,Via Campi Flegrei,
34, 80078 POZZUOLI, ITALIA
Methyl methacrylate (MMA) copolymers with 2, 3 epoxypropyl
methacrylate (GMA) and styrene (S) copolymers with GMA were tested as
matrices for the coupling of the bioactive products. The preparation of
polymeric matrices was realized by classic emulsion polymerization (CW)
and also comparatively obtained through unconventional procedure in the
presence of a magnetic field (MF) of 1500 Gs intensity.
In the paper, the albumin (BSA) adsorption onto the
synthesised polymeric matrices, it was study. Thus, it was compared
the coupling process performed with or without the magnetic field
presence.
It was also studied the influence of the temperature, pH and ratio
between BSA and polymer upon the albumin adsorption yield. The yield of
BSA adsorption is higher in case of the copolymers matrices synthesised
in the MF presence. At the same time the BSA adsorption performed in
the MF presence evidences decreased yields of coupling.
Keywords: albumin adsorption, magnetic field effect, methyl methacrylate
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P-7-04. Azaheterocycles: Effect on Germination and Seedling Growth on Plants
Marian Risca, Elena I. Perju, Maria Caprosu, Gabi Drochioiu, Ionel Mangalagiu* “Al. I. Cuza” University, Organic Chemistry Dep., 11 Carol I Bd., 700506 Iasi – 6 Romania, email: [email protected]
Higher plants are recognized as excellent indicators of
cytogenetic and mutagenic effects of some chemicals and are applicable
for the etection of environmental noxious compounds. Recently it was
proved that some diazine salts with similar structures to phenoxyacetic or
indolylacetic phytohormones, could have on plants either inhibitory or
stimulating activity, according with their concentrations. Having in view the
above consideration, the emphasis of this work was to synthesize new
salts analogous of phytohormones and to test their influence on plants
germination. The cycloimmonium salts were prepared treating the
nitrogen heterocyles with variously halogenated derivatives, under
classical conditions or under ultrasounds irradiation.
Studies on the germination and seedling growth of Norway spruce
have been done. The experiments were conducted in controlled
temperature room and results showed that germination percentages,
shoot and root lengths and fresh weights varied as a function of
concentration and structure of each investigated compound. Higher
concentrated solutions of the investigated compounds exhibited highly
inhibitory activity on spruce germination, while the lower concentrations
resulted in a stimulating action, especially for the radical’s length.
Acknowledgements: to CNCSIS Bucharest, grant no.
1155/2006, for financial support.
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P-7-05. Synthesis of Highly Fluorescent Materials through Eco-friendly Methods
Gheorghita Zbancioc, Costel Moldoveanu, Maria Caprosu, Ionel Mangalagiu* “Al. I. Cuza” University of Iasi, Organic and Biochemistry Department, Bd. Carol 11, 700506, Iasi, Romania,e-mail: [email protected]
The synthesis of highly fluorescent material continues to arouse strong
interest in the field of biochemistry as well as in the field of material science
because of their fascinating applications such as sensors and biosensors,
electroluminescent materials, lasers, and other semiconductor devices.1-4
The overall goal of this work was to develop a new, efficient and general
method for preparation of highly fluorescent pyrrolo- diazine derivatives
using MW. In this respect, variously dazinium ylides (derived from
pyridazine, phthalazine and pyrimidine), generated in situ from the
corresponding cycloimmonium salts, were treated with activated
electronwithdrawing –alkynes or alkenes under MW and classical heating
conditions.
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Under MW heating the reaction times decrease dramatically (from
several hours to 5 min.) and the amount of solvent used had decreased
also (several times). Most remarkably the yields are much higher with the
use of MW heating, being, in some cases, almost double. Stereo - and
region - chemistry of the Huisgen 3+2 dipolar cycloaddition it was also
discussed.
Acknowledgements: to CNCSIS Bucharest, Romania (grant
A, cod 1155/2006) and NATO(PDD(CP)-(CBP.EAP.CLG 982499)
/20.11.2005), for financial support.
References
1. Valeur, B.’Molecular Fluorescence’, Willey-VCH, Weinheim, 2002. 2. Lee, S.; Nakamura, T.; Tutsui, T. Org. Lett. 2001, 3, 2005. 3. Thompson, M.A.; Forrest, S.R. Nature 2000, 403, 750. 4. a). Rotaru, A.V.; Druta, I.I.; Oeser, T.; Muller, T.J. Helv. Chim. Acta
2005, 88, 1798; b). Mitsumori, T.; Bendikov, M.; Sedo, J.; Wudl, F. Chem. Mater.
2003, 15, 3759; c). Zbancioc, Ghe.; Mangalagiu, I.I. Syn Lett. 2006, 5, 804.
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P-7-06. Optical Properties of Ni(NiOx)/Al2O3 Cermet Solar Absorber Deposited by Spray Pyrolysis
Elena Purghel*, Luminita Isac*, Anca Duta* * The Centre: Product Design for Sustainable Development,
Transilvania University of Brasov, Eroilor 29, 500036, Romania, e-mail: [email protected]
In order to increase the conversion efficiency of solar energy into
thermal energy, a selective surface with high absorbance (α>0.90) over
the solar spectrum and low emittance (ε<0.1) in the infrared domain is
required. Cermets, consisting of fine metal particles embedded in a
ceramic matrix, are considered promising materials for selective surfaces
due to their optical properties and costs. The Ni(NiOx)/Al2O3 cermets, with
maximum absorption (α = 0.92÷0.98) and minimum emission (ε =
0.07÷0.03), are widely used as absorbers of solar energy in solar
selective coatings.
The Ni/NiOx films were deposited onto micro-glass and Al2O3/micro-glass
substrates by spray pyrolysis (SPD). As precursors, aqua-ethanolic
solutions of nickel chloride and nickel acetate were used. Deposition
parameters such as temperature, precursor’s concentration and the
number of spraying sequences were varied for optimizing the nickel
cermet properties. The optical properties of the films (UV-VIS, IR) were
correlated with their chemical composition, crystalline structure and
morphology.
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P-7-07. Synthesis of New Imidazole Derivatives of Potential Interest as Phytohormones under Ultrasounds Irradiation
Marian Risca, Elena I. Perju, Maria Caprosu, Gabi Drochioiu, Ionel Mangalagiu* “Al. I. Cuza” University, Organic Chemistry Dep., 11 Carol I Bd., 700506 Iasi – 6 Romania, email:[email protected]
It is well know that imidazole is one of the most important
biologically potent heterocycle. Certain imidazole derivatives was proved
to be phytohormones, and could have on plants either inhibitory or
stimulating activity, according with their concentrations. Having in view the
above consideration, the emphasis of this work was to synthetise new
imidazole derivatives analogous of phytohormones and to test their
influence on plants germination. The cycloimmonium salts were prepared
treating the imidazole heterocyles with variously halogenated derivatives,
under classical conditions or under ultrasounds irradiation.
Studies on the germination and seedling growth of Norway spruce
have been done. The experiments were conducted in controlled
temperature room and results showed that germination percentages,
shoot and root lengths and fresh weights varied as a function of
concentration and structure of each investigated compound. Certain
influence on germination was found, the imidazole derivatives being of
interest as grow up factors.
Acknowledgements: to CNCSIS Bucharest, grant no.
1155/2006, for financial support.
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P-7-08. Liant hidraulic multifunctional pe baza de ciment portland
Dumitrescu Cristina*, Menicu Mirela*, Georgeta Voicu**, Ionela Popovici*** * S.C. CEPROCIM S.A. ** Universitatea POLITEHNICA Bucuresti *** Universitatea Ovidius Constanta
Prezenta lucrare face obiectul unui proiect CEEX si are ca
obiectiv final realizarea unui ciment cu adaos de calcar fin macinat si alte
adaosuri corectoare cum sunt silicea ultrafina, TiO2 si aditivi
superplastifianti.
Adaosurile corectoare au rolul de a influenta mecanismul
hidratarii cimentului, compozitia fazala si microstructura cimentului intarit.
De asemenea adaosul de TiO2 ii confera produsului finit proprietatea de
autocuratare, fiind eficace in reducerea anumitor poluanti (NOx,
hidrocarburi aromatice etc.).
Prin analize de difractie de raze X, ATD, RMN, SEM, TEM si
analize chimice s-au obtinut informatii privind microstructura cimentului
intarit, compozitia mineralogica si porozitatea la scara nano (2-50 nm) a
acestuia.
Aceste informatii permit imbunatatirea performantelor materialului
cimentoid propus a se realiza.
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P-7-09. Iron Complexes with Ligands Containing Siloxanes
M. Cazacu1, A. Vlad1 F. Iacomi2, L.V.Giurgiu3 1 “P. Poni” Institute of Macromolecular Chemistry Iasi, Romania 2 “Al.I.Cuza” University, Faculty of Physics, Iasi. Romania 3 ITIM Cluj-Napoca, Romania
A series of iron complexes with siloxane-containing Schiff bases
ligands have been prepared by one pot reaction and characterized [1-3].
Depending on the carbonylic compound nature, either macromolecular or
low molecular chelates have been obtained. The polyesteric structures
based on the difunctional chelate monomer have lower thermal stability as
compared with directly synthesized macromolecular chelate. A low iron
content was obtained in all synthesized chelates in the chosen conditions.
Based on IR and ESR spectra, in all these compounds, the complexed
iron was found to be paramagnetic. References
1. Welch, K.D., Davis, T.Z., Aust, S.D. Arch.Biochem. Biophys, 397 (2002) 360.
2. Gabryszewski, M. Spectr. Lett. 34 (2001) 57. 3. J. Sima, Croatica Chemica Acta, 74(3) (2001) 593.
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P-7-10. Nanostructured Materials Type Layered Double Hydroxides Intercalated with Piroxicam: Preparation and Characterization
Mihaela Frunza1, Ionel Marcel Popa1, Viorel Melnig2 1 Technical University, Iasi, Romania, 2 University Al.I.Cuza Iasi, Romania, [email protected]
Piroxicam is a non-steroidal anti-inflammatory drug used to
relieve the symptoms of rheumatoid and osteoarthritis, primary
dysmenorrhoea, postoperative pain; and act as an analgesic, especially
where there is an inflammatory component. Piroxicam use can result in
gastrointestinal toxicity, tinnitus, dizziness, headache, rash, and pruritus.
The most severe adverse reactions are peptic ulceration and
gastrointestinal bleeding.
The pharmacological studies show that intercalation of the drugs
in the layered double hydroxides (LDH) has a synergic effect. On one
hand the presence of the layered double hydroxides ensures a buffered
environment and on the other hand it reduces the ulcerating side effects
of the intercalated drug [1-3].
In this work we have investigated the intercalation behavior of
piroxicam into LDHs by coprecipitation method and ion-exchange
reaction. The intercalated compounds were examined by X-ray diffraction
(XRD), FTIR spectroscopy, thermo gravimetric analysis and SEM
techniques.
References
1 Z. Wang, E. Wang, L. Gao and L. Xu, J. Solid State Chem. 178, 736-741,(2005).
2 B. Li, J. He, D. G. Evans and X. Duan, Appl. Clay Sci., 27, 3-4, 199-207, (2004).
3 V. Ambrogi, G. Fardella, G. Grandolini, L. Perioli, Int. J. Pharm., 220, 23-32. (2001).
Acknowledgements: This work has been supported by Ministry
of Education and Research Romania, by CNCSIS cod 53/2006.
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