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Studies on the Synthesis of magnetic iron oxide nanoparticles
and its
environmental application for the removal of arsenic from
water
A Report Submitted for Ph.D. Registration
in the partial fulfilment for the Award of the Ph.D. Degree
Submitted by:
Uttam Kumar Sahu
Roll No. : 514CY6006
Under the Guidance of
Prof. Raj Kishore Patel
Prof. Siba Sankar Mohapatra
Department of Chemistry
National Institute of Technology
Rourkela-769008, Odisha, India
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Introduction
Water pollution is the contamination of water bodies (e.g.
lakes, rivers, oceans and ground
water) due to discharge of effluents and harmful compounds
directly or indirectly either by
natural or anthropogenic activities into water bodies without
adequate treatment. The water
pollution is described as the water with enough harmful or
objectionable material to damage
the quality of water. It is one of the major global problems
which are concerned to
everybody. It has been reported that more than 14,000 people die
every day worldwide
because of taking contaminated water. In addition to the acute
problems of water pollution in
developing countries, industrialized countries continue to
struggle with pollution problems.
Water pollution has many sources and characteristics. 10 to 15
billion pounds of waste
materials like garbage, effluents from municipalities,
pesticides and industries, enters to
different water bodies throughout the Globe.
Among hazardous materials, arsenic compounds are one among the
priority hazardous
materials, due to its carcinogenic effect and other environment
effect. The compounds are found
in soil and water which require removal as it affects both human
and aquatic life. Acute and
chronic poisoning may cause nausea, dryness of the mouth and
gastro-intestinal symptoms. Long-
term exposure of arsenic may cause damage to lungs, bladder and
kidney as well as pigmentation
changes. It also causes skin cancer According to WHO, the
maximum permissible limit of
arsenic in water is 0.01 mg/L. Arsenic exists in both organic
and inorganic forms in nature and
the inorganic arsenic is more poisonous as compared to organic
arsenic because it is highly
soluble in water.1 The toxicity of arsenic depends on its
speciation and the most significant forms
for natural exposure of arsenic in drinking water are its
inorganic forms, arsenite H2AsO3,
H2AsO3− and arsenate H2AsO4
−, HAsO42−. As(III) and As(V) are both linked to energy
related functions of mitochondria in a cell. As (III) has very
high affinity for sulfhydryl
groups in protein leading to formation of thiolated species
which inhibit the enzyme
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activity. As(V) compete with phosphate and limit oxidative
phosphorylation which is key
to the high bond energy of ATP molecules. As(V) is less toxic
than As(III), but in the most of
the aquatic environments arsenic is present in its oxidized
form.2 So removal of arsenic from the
water now is a global level challenge. In the recent past,
several methods have been used in order
to remove arsenic from water such as coagulation-flocculation,
ion exchange, reverse osmosis,
membrane filtration and adsorption. Among all, adsorption is
very easy, economical, less time
consuming and are efficient even at low concentration of arsenic
provide the adsorbing material
are suitable.
Researcher have used several adsorbent but iron oxide
nanoparticles, iron based bimetal oxide
and iron nanocomposite materials as a adsorbent are more
favourable because;
These particles have advantages like large surface area, high
number of active sites and
high magnetic properties and environmental friendly.
These properties are suitable for high adsorption efficiency,
high removal rate of
contaminants and easy and rapid separation of adsorbent from
solution via magnetic field.
Hence uniformly accessible pores to ensure high adsorption
kinetics and high surface area
to provide high density of adsorption sites for the ease in
operation.
However, applicability of the iron nanoparticles is shown to
suffer from their poor
chemical stability and mechanical strength and tendency to
aggregate. Furthermore, these
nanoparticles as such are not suitable for fixed-bed column or
flow-through systems due
to for instance mass transport problems and significant pressure
drops.
Hence iron oxide nanoparticles is activated with clay materials
and fibrous hybrid
material.
Hence bimetal oxides or composites are synthesized by
incorporating metal elements
such as Zr, Ti, Ce, Co and Mn, into iron oxides have shown a
superior performance of
arsenic adsorption.
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Decorating cerium oxide with iron oxides can significantly
improve the arsenic uptake
performance in waste water.
So the materials with high specific surface area and uniformly
dispersed iron oxides can
be used as an ideal materials for arsenic removal with the
advantages of large capacity,
fast adsorption, easy operation, and long cyclic stability
Literature Survey
Water-Dispersible Magnetite-Reduced Graphene Oxide Composites
for Arsenic Removal from
drinking water was investigated.3 The composites with very small
size about 10nm was formed.
The effect of initial concentration, pH, and contact time were
investigated. As(V) removal
was strongly pH dependent and pH 4, maximum removal of arsenate
took place. Langmuir
adsorption isotherms was fitted with the experimental data.
Adsorption kinetics was governed
by a pseudo first order rate equation cases. The composites are
superparamagnetic at room
temperature so in arsenic solution it can be separated by an
external magnetic field. The
composites show near complete (over 99.9%) arsenic removal
within 1 ppb, they are
practically usable for arsenic separation from water.
Composite materials, containing magnetic nanoparticles and
cellulose, were synthesized by
one-step co-precipitation using NaOH-thiourea-urea aqueous
solution for cellulose
dissolution and used for arsenic removal from aqueous
solutions.4 It was reported that for the
removal of arsenate batch adsorption experiments was conducted
with variation of various
parameters such as adsorbent dose, contact time, equilibrium pH,
initial arsenate
concentration, and isotherms. It was reported that the
percentage removal was increase
gradually with decrease of pH and maximum removal was 32.11 mg/g
at pH ∼2. The
Arsenate adsorption was well fitted by Langmuir adsorption
isotherm with correlation
coefficient R2 = 0.996.
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K. J. Reddy et. al.5 shows a novel arsenic removal process for
water using cupric oxide
nanoparticles. A reactor with CuO nanoparticles was developed to
conduct continuous flow-
through experiments to filter arsenic from water samples.
Samples from the flow-through
reactor were collected at a regular interval and analysed for
arsenic and other chemical
components (e.g., pH, major and trace elements). At different
time interval from 0 to 1200
minute the sample were examined in neutral pH. Arsenic mass
balance data from
regeneration studies suggested that 99% of input arsenic
concentration was recovered. Kyle J.
McDonald et. al.6 his study demonstrates the intrinsic abilities
of cupric oxide nanoparticles
(CuO-NP) towards arsenic adsorption and the development of a
point-of-use filter for field
application. Field experiments were conducted with a
point-of-use filter, coupled with real-
time arsenic monitoring, to remove arsenic from domestic
groundwater samples shows that
the zeta potential of CuO nanoparticles at approximately pH 9.4
± 0.4, allows for adsorption
of arsenic under most naturally occurring drinking water
systems. At lower pH < pHpzc
arsenate was adsorbed.
Z. Wen et al. 7 used a magnetic mesoporous iron manganese
bimetal oxides in which has the
high surface area of about 154.73 m2/g. at pH 3 maximum removal
of arsenate took place.
The experimental data best fitted with the Freundlich isotherm
with uptake capacity of 35.32
mg/g with correlation coefficient 0.99. The regeneration study
was done and up to its six
cycle the adsorption capacity was nearly same about 32.15
mg/g.
Green synthesis of Fe2O3 nanoparticles for arsenic(V)
remediation with a novel aspect for
sludge management by D. Mukherjee et al.8 Here a natural Aloe
Vera leaf is used for the
preparation and used for the removal of arsenate. The effect of
pH, particle dosage and
initial arsenic concentration on arsenic adsorption was
investigated using response
surface methodology involving five levels for each parameter.
The nanoparticles showed
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a high sorption capacity of 38.48 mg/g in the experimental range
of concentration
compared to other inorganic oxide based adsorbents.
D. Morillo et al.9 prepared 3-mercaptopropanoic acid-coated
superparamagnetic iron oxide
nanoparticles for arsenate removal and found that the arsenate
adsorption to be highly pH-
dependent, and the maximum adsorption was attained in less than
60 min. at pH 3.8
maximum removal took place. The effect of adsorbent dose and
initial arsenic concentration
also studied in the process. Adsorption data well fitted with
the Langmuir isotherm with
maximum uptake capacity of 1.9 mm/g. Again D. Morillo et
al.10
prepared an adsorbent of
Novel Forager Sponge-loaded superparamagnetic iron oxide
nanoparticles and used for
removal of arsenic in acidic wastewater. In this case also
maximum adsorption took place at
pH 3.8 and the experimental data best fitted with the Langmuir
adsorption isotherm with
uptake capacity of 12.1 mm/g. Though many process and materials
are well documented but
till date, an efficient, environmental friendly, cost effective
and widely acceptable process by
using a suitable adsorbent for the removal of arsenic has not
been proposed in spite of great
potential exist for the development of adsorbent.
Research gap
In all the reported processes, arsenic is removed in different
percentage but there are some
disadvantages. The major disadvantages are: no regeneration of
adsorbent, use of large
amount of adsorbent, complicated experimental set up, arsenic
removal is less than
permissible limit and disposal of adsorbent etc. To overcome
these disadvantages, the present
work is undertaken.
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Objectives of the study
Keeping all the facts in literature in mind, the present work
has been undertaken with the following
objective:
To establish the synthesis of iron oxide nanoparticles by
suitable process, specially
emphasizing on microemulsion method and to modify the iron oxide
nanoparticles to be
used for the removal of arsenic from water.
To understood the detail mechanism, kinetics, isotherm of the
adsorption process.
To optimize the process parameters using the Response surface
methodology (RSM)
To validate the data by performing the experiment with actual
polluted water from the field.
To develop an engineer low cost model (inexpensive, locally
available materials,
simple construction method, simple and easy maintenance) for a
versatile water
filter suitable for arsenic rich water purification.
Material & Methods
Attempt will be made to prepare adsorption media incorporating
iron oxide nanoparticles in
different matrix by suitable process (especially microemultion
process) with variation of process
parameters to establish the mechanism of particle formation
which can be effectively used to
remove arsenic from water. The removal efficiency of arsenic
from water will be studied as a
function of contact time, pH of solution, initial concentration
of adsorbate, absorbent dose and
temperature. The mechanism of this process will also be
evaluated by analysing kinetic and
adsorption model. Finally optimum condition will be evaluated.
The various thermodynamic
parameters will be measured to ascertain the feasibility of the
process. Subsequently a model will be
designed for field application by incorporating the data of the
above studies. The process will be
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developed which will be suitable for rural setting and will
sustain availability of safe drinking water.
Subsequently the process developed will be evaluated on the
mathematical modelling.
Work already done
1st Part
CeO2@Fe2O3 mixed oxide is synthesized by solvothermal process
and used for the
removal of As(V) from aqueous solution.
The CeO2@Fe2O3 mixed oxide material is characterized by XRD, BET
surface area
measurement, FTIR, Zeta potential and SEM.
The effect of various parameters like adsorbent dose, pH,
initial arsenate
concentration, contact time, kinetics and isotherms has been
investigated to determine
the adsorption capacity of the mixed oxide CeO2@Fe2O3 mixed
oxide.
The adsorption kinetic study shows that the overall adsorption
process followed the
pseudo-second-order kinetics. The maximum adsorption capacity
calculated from
Langmuir isotherm model is found to be 32.12 mg/g at solution pH
3.
The interfering anions reduced the arsenate adsorption in the
order of PO43-
> CO32-
>
SO42-
> NO3- ≈ Cl
-.
Desorption experiments are carried out by taking different
concentration of NaOH
solution.
2nd Part
Fe3O4 nanoparticles is synthesized by water in oil microemultion
process.
A novel biodegradable surfactant Extron is used as surfactant in
this process.
The nanoparticles is characterised by various instrumental
technique such as XRD,
FESEM, TEM, BET analyser, VSM and FTIR technique.
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Work to be done
Synthesis and characterization of more novel iron oxide
nanoparticles based
adsorption media by microemultion process.
Separation of iron oxide nanoparticles and reuse of oil &
surfactants for the
preparation of another batch iron oxide nanoparticles by the
same process.
Development of a dynamic model for nanoparticle formation via
w/o microemulsions.
Batch adsorption studies on the arsenic by synthesized iron
oxide nanoparticles and
compares adsorption efficiencies with other materials.
Optimization of batch adsorption process parameters with design
of experiments by
RSM methods.
Development of a versatile arsenic removal water filter and its
field application.
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ROAD MAP OF MY RESEARCH WORK
Uttam Kumar Sahu Roll No.-514CY6006
Date of Enrolment:-22th July 2014
Time
Activity
I Year II Year III Year IV Year
July 01
2014 to
Dec 31,
2014
Jan 01
2015 to
Jun 30,
2015
July 01
2015 to
Dec 31,
2015
Jan 01
2016 to
Jun 30,
2016
July 01
2016 to
Dec 31,
2016
Jan 01
2017 to
Jun 30,
2017
July 01
2017 to
Dec 31,
2017
Jan 01
2018 to
Jun 30,
2018
Course Work
Literature
Survey
Experimental
Work
Analysis of
experimental
work
Writing of
manuscript
Writing of
thesis and
submission
Course work
Subject ID Name of the subject Credit Grade obtained
CY611 Advanced Analytical Chemistry 03 B
CY616 Nuclear Magnetic Resonance Spectroscopy 03 B
CY622 Organometallics Compounds and their Application 03 B
CY623 Catalysis- Principle and Application 03 B
CY632 Chemistry of Nanomaterial 03 B
CY636 Specials topics in Physical Chemistry 03 B
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Workshops and Conferences attended
1. Presented a poster “Synthesis of magnetic iron oxide
nanoparticles (Fe3O4) by
microemultion process and its study on the removal of As(III)
from aqueous solution”
in international conference on “Innovative application of
chemistry on Pharmacology
and technology” held on 6th-8th February, 2015 at Berhampur
University.
2. Participated in the work shop on “Short Term Course on
Mathematical Modelling and
its applications” held on 22th-24th February, 2015 at NIT,
Rourkela, Odisha.
Paper publication
1. Manoj Kumar Sahu, Uttam Kumar Sahu and Raj Kishore Patel,
Adsorption of
safranin-O dye on CO2 neutralized activated red mud waste:
process modelling,
analysis and optimization using statistical design. RSC
Adv.,2015, 5, 42294
2. Uttam Kumar Sahu, Manoj Kumar Sahu and Raj Kishore Patel,
Synthesis and
characterization of CeO2@Fe2O3 mixed oxide for the removal of
As(V) from aqueous
solution, is under review in New Journal of Chemistry.
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Reference
1 W. Li, D. Chen, F. Xia, J. Z. Y. Tan, P. P. Huang, W. G. Song,
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Environ. Sci. Nano, 2015.
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4 V. A. Online, X. Yu, S. Tong, M. Ge, J. Zuo, C. Cao and W.
Song, 2013, 959–965.
5 K. J. Reddy, K. J. Mcdonald and H. King, J. Colloid Interface
Sci., 2013, 397, 96–102.
6 K. J. McDonald, B. Reynolds and K. J. Reddy, Sci. Rep., 2015,
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7 Z. Wen, C. Dai, Y. Zhu and Y. Zhang, RSC Adv., 2014, 5,
4058–4068.
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Pharmacol., 2016, 4, 639–
650.
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