Faculty of Mechanical Science and Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering Characterisation of nanomaterial release during their lifecycle Regulatory Challenges in Risk Assessment of Nanomaterials Topic 2: Measurement and characterization of nanomaterials Topical Scientific Workshop, ECHA, Helsinki, 2014-10-23/24 Michael Stintz Institute of Process Engineering and Environmental Technology, Research Group Mechanical Process Engineering
Transcript
Faculty of Mechanical Science and Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Characterisation of nanomaterial release during their lifecycle
Regulatory Challenges in Risk Assessment of Nanomaterials Topic 2: Measurement and characterization of nanomaterials Topical Scientific Workshop, ECHA, Helsinki, 2014-10-23/24
Michael Stintz Institute of Process Engineering and Environmental Technology, Research Group Mechanical Process Engineering
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 2
First defined – Release from powders
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 3
Published studies on nano-object release into air suffer more or less from three problems, i.e. a consistent terminology, standardized metrological procedures and the kind of data evaluation. Thus, a quantitative comparison between the different studies was often impossible, if necessary parameters are missing. This hinders also the conclusion on real exposure situations.
To fill this gap, ISO/TC 229/JWG 2/PG 10 has developed in a first step the technical specification ISO/TS 12025:2012, which is a general framework for determining airborne release of nano-objects from nanostructured powders by means of aerosol analysis.
The TS provides information on the methodology for nano-object release quantification that covers beside necessary measurands and process parameters also the presentation of measurement results by specific release numbers. It supports also standardization of nano-object release testing of nanocomposites, e.g. by abrasion procedures.
Nanoparticle Release Testing
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 4
ISO/TS 12025:2012, Nanotechnologies — Quantification of nano-object release from powders by generation of aerosols
nano-object number release total number of nano-objects, released from a sample as a consequence of a disturbance nano-object release rate total number of nano-objects, released per second as a consequence of a disturbance mass specific nano-object number release Nano-object number release, divided by the mass of the sample before the disturbance
Symbol Quantity SI Unit
n nano-object number release dimensionless
nt nano-object release rate s-1
cn nano-object aerosol number concentration m-3
nm mass specific nano-object number release kg-1
Vt aerosol volume flow rate m3 s-1
Definition of Nanoparticle Release
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
DMAw/ neutralizer
CPC
APS
OPC
SMPS
HEPAfilter
Vortex Shaker
Make-up air
Cyclone
Cyclone
HEPAfilter
Compressed dry air
Flowmeter
Valve
Dilution
HEPAfilter
PumpFlowmeter
Valve
CPC
Compressed dry air
HEPAfilter
Flowmeter
Valve
Exce
ss
2.5 μmcut
15 μmcut
Informative Example Vortex Shaker method
Nanoparticle Release from Powders
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 6
Limits from workplace background: Koponen IK, Jensen KA, Schneider T: Sanding dust from nanoparticlecontaining paints: physical characterisation. J Phys: Conf Ser 2009, 151:012048. Kuhlbusch et al.: Nanoparticle exposure at nanotechnology workplaces: A review, Göhler, Stintz: 4. Nanoparticle release studies under laboratory conditions Particle and Fibre Toxicology 2011, 8:22
Workplace Measurement
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 7
Nanocomposites testing under lab conditions
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Nr. 8
1. Test Setup TUD
Abrasion test under particle free atmosphere
Taber Abraser for stressing samples
Detection of aerosol particle emission with SMPS
Additional, microscopic investigations
CEFIC Workshop June 2008 in Brussels:
J. Aerosol Science, 2009, Vol 40, No 3, pp 209-217.
Vorbau M, Hillemann L and Stintz M, TU Dresden: Method for the characterization of the abrasion induced nanoparticle release into air from surface coatings
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Nanosafe November 2008 in Grenoble: Journal of Physics: Conference Series 170 (2009) 012014 Arnaud Guiot, Luana Golanski and François Tardif CEA-Liten: Measurement of nanoparticle removal by abrasion
Nr. 9
1. Test Setup CEA
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
nanoparticle release characterization for exposure assessment no harmonized methodology data comparability is very limited complex metrological challenge
objective risk assessment by systematic exposure characterization in laboratory qualitative & quantitative particle release characterization (Göhler et. al. 2010) 2 projects based on sanding of artificially aged/weathered nano-composites
Göhler, Stintz et al. Journal of Physics: Conference Series 429 (2013) 012045.
sample supply
sample treatment
aerosol sampling
aerosol sampling
background aerosol
phys. & chem. prop. type of quantity
instruments
measurands type of quantity
transferability
comparability
sample preparation
aerosolgeneration
aerosol conditioning
aerosol analysis
dataevaluation
sample conditioning
characterization
sample selection
General Release Test Cycle, e.g. Sanding
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 10
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
sample chamber
blower blower
humidifier
heater
filter
ventilation circuit
xenon-arc lamp cooling
controller
UVA-Lamps
detectors
Materials - Sample preparation & conditioning Project A
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Nanoparticle Release Test - Sanding
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Results - Data evaluation aerosol measurement data particle number concentration without additional information not suitable as release parameter number-weighted particle size distributions
independent release parameter fractional particle release numbers nA (e.g. x ≤ 100 nm, x< 10 µm, x ≥ 1 µm) relation to stressed area area specific release numbers [104…105 (particles ≤ 100 nm) /cm²]
0.005 0.05 0.5 5 50
0.00E+00
4.00E+02
8.00E+02
1.20E+03
1.60E+03
2.00E+03
0.0E+00
4.0E+02
8.0E+02
1.2E+03
1.6E+03
2.0E+03
0.005 0.05 0.5 5 50
aerodynamic particle diameter [µm]
c n·q
0*=
dc n
/dlo
gx
[cm
-3]
electrical mobility diameter [µm]
EEPSAPS
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Nanoparticle Release Test - Sanding
Göhler, Stintz et al. Journal of Physics: Conference Series 429 (2013) 012045.
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 15
ISO/TC 256 NWIP:2014 Pigments and extenders — Determination of experimentally simulated nano-object release from paints, varnishes and pigmented plastics Scope This standard specifies a method for experimental determination of the release of nanoscale pigments and extenders into the environment following an abrasive stress of paints, varnishes and pigmented plastics. The method is used to evaluate if and how many particles of defined size and distribution under stress (type and height of applied energy) are released from surfaces and emitted into the environment. The samples may be aged, weathered or otherwise conditioned to simulate the whole lifecycle.
Now – ISO/TC 256 Standardization project
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 16
Göhler, Stintz: Granulometric characterization of airborne particulate release during spray application of nanoparticle-doped coatings. J Nanopart Res (2014) 16:2520
Nanoparticle Release Test - Spraying
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
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Whole setup scheme for spray application, aerosol conditioning and characterization
Nanoparticle Release Test - Spraying
APS3321
ESP
-3 kV / +13 kV0.3 L∙min-1
3 L∙min-1
P
Kr85
3077
flow splitter
0.3 L∙min-1
CPC 23022A
EEPS3090
DDS560
compressed air supply
blower≤ 400 L·min-1
aerosol generation
aerosol conditioning
aerosol characterization
MFMM40211
2.5 bar
VKL10
VKL10
HEPA-filter
Kr85
3077
HEPA-filter
10 L∙min-1
5.0 L∙min-1
2.7 L∙min-1
2.3 L∙min-1
1-5 L∙min-1
spray-channel
spray module (no. 2)
exhaust, atmospherically decoupled
HEPA-filter
2.5 bar
HEPA-filter
P
compressed air supply
HEPA-filter
two-waystopcock
2.5 bar
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
TEM-image of a synthetic and fractal SiO2-aggregat (≈ 500 nm) containing sintered nanoscale primary particles (≈ 18 nm)
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 18
Example: Nanostructured Particles
100 nm
2000 nm
SEM-image of a dried spray droplet (≈ 5µm) made of acrylate topcoat with embedded TiO2 pigment particles (≈ 200 nm) and embedded iron oxide nanoparticles (< 100 nm)
which fulfil the EC recommendation on the definition of nanomaterials.
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 19
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 20
Standardization/TC Structure
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Standardization in nanoparticle characterization is performed in 15 Working Groups within ISO/TC 24/SC 4. Additionally to imaging methods for morphology inspection of single particles, aerosol measurement devices have some benefits for exposure analysis compared with particle measurement techniques for liquid dispersions (i.e. emulsions, suspensions or combinations of them), for instance the ability of providing absolute count numbers or the independency from specific material properties (e.g. from the index of refraction).
A fundamental aerosol measurement principle that allows the characterization of particles down to a view nanometre is the electrical mobility analysis as described within ISO 15900:2009. One problem from metrological view, which still exists for aerosol measurement technology, is the lack of a concentration reference material. An important step in this direction represents the international standard draft (DIS) ISO/DIS 27891:2013 for the calibration of condensation counters.
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 21
Nanoparticles in Aerosols
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
In the field of liquid dispersion characterization, a fundamental challenge is the characterization of the dispersion stability, i.e. “the absence of change in specified properties over a given timescale”. Therefore, the technical report ISO/TR 13097:2013 was issued by WG 16, which describes two different approaches to determine relative property changes.
Especially in larger cluster research projects, dealing with fate, exposure and hazard of nanomaterials the sample preparation turned out to be the deciding step, e.g. for risk assessment of TiO2.
Zeta potential measurement proved to be a necessary tool for checking dilution and stabilization protocols. Therefore, WG 17 issued methods for zeta potential determination within ISO 13099, which consists currently of two standards and one final draft of an ISO standard (FDIS).
Respecting the preparation preconditions comparable and reproducible particle or agglomerate size measurement by centrifugal sedimentation or hydrodynamic mobility analysis (e.g. by dynamic light scattering - DLS) can be achieved.
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Nanoparticles in Suspensions
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
WG 1 "Representation of analysis data" WG 2 "Sedimentation, Classification" WG 3 "Pore Size distribution, porosity" WG 5 "Electrical sensing zone methods" WG 6 "Laser diffraction methods" WG 7 "Dynamic light scattering" WG 8 "Image Analysis methods" WG 9 "Single Particle light interaction methods" WG 10 "Small angle X-ray scattering" WG 11 "Sample preparation" WG 12 "Electrical mobility and number concentration analysis for aerosol particles" WG 14 "Acoustic methods" WG 15 "Focused scanning beam techniques" WG 16 “Characterisation of particle dispersion in liquids” WG 17 "Methods for zeta potential determination"
(16 P-Members, 12 O-Members, Liaison to ISO TC 229 and CEN TC 352)
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ISO/TC 24/SC 4 Particle Characterization
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Concept of particle number concentration standard (detection efficiency determin.)
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ISO/FDIS 27891:2014 Aerosol particle number concentration — Calibration of condensation particle number counters
optical detector
condensation chamber
WG 12 Aerosol Measurement
Condensation
Particle Counter
Optical Particle Counter
10 nm 100 nm 1000 nm
Aerosol
Electrometer
1 cm-3
100 cm-3
10000 cm-3
1 nm
Part
icle
Con
cent
ratio
n
Particle Size
ISO 15900:2009 Determin. of particle size distribution — Differential electrical mobility analysis for aerosol particles
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 25
Nanoparticle Double Layer Interaction
K. Schießl, F. Babick et al. Advanced Powder Technology 23 (2012) 139–147
WG 17 Zeta Potential Measurement
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 26
Nowack et al.: Potential release scenarios for carbon nanotubes used in composites, Environment International 59 (2013) 1–11
CNT Composites - Scenarios
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
From characterisation of nanomaterial release during their lifecycle: - Particle size distribution and concentration alone are not sufficient - Sample amount related quantities (e.g. numbers) and also larger particle
size ranges for plausibility balancing are necessary
- Sample treatment processes can be more important than sample material
- Matrix and nanoparticle embedding properties are important - Nanoparticle release from non-nanomaterials like polymer matrices
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Results
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
For characterisation of nanomaterial release during their lifecycle: - Methodology is now available and subject of international standardization. - World wide community has test methods adopted and validation and ILC
started. - Estimation of potential release (Precaution) on basis of TEM-images of
prepared nano-object structures is not longer a sound scientific basis. (Apart from granulometric analyses by imaging methods (SEM, TEM), the
metrological determination of characteristic properties allowing the classification of a material as a nanomaterial in accordance with the recommendation of the European Commission is still a complex scientific and technical challenge.)
The measurement of aggregate/agglomerate size distributions under defined conditions (e.g. dispersing procedures, release scenarios) is essential for characterizing particulate systems.
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Conclusions
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 29
Thank you!
Attachments for further information: Nanosafetycluster ILSI NanoRelease Consumer Products NANOfutures
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
Nanomaterials from release to exposure Kai Savolainen (coordinator), Ulrika Backman, Derk Brouwer, Bengt Fadeel, Teresa Fernandes, Thomas Kuhlbusch, Robert Landsiedel, Iseult Lynch, and Lea Pylkkänen: Nanosafety in Europe 2015-2025: Towards Safe and Sustainable Nanomaterials and Nanotechnology Innovations. 2013 Finnish Institute of Occupational Health, http://www.nanosafetycluster.eu/news/83/66/Nanosafety-in-Europe-2015---2025.html
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 30
NanoSafetyCluster: Study 2013
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
1. Production Possible release during production may occur through leaks into water and air in closed systems or open production processes.
(NANOSH,CarboSafe, nanoGEM) 2. Handling and use Handling and use covers several process-related stages e.g. handling of powders, diffuse emission from production plants, mechanical treatment of nanomaterials 3. Aging Aging encompasses all processes taking place in the environment such as selective degradation, wash-out, increased brittleness of the material
General processes and areas of possible release and exposure:
ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 31
NanoSafetyCluster Study 2013
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
4. End of Life (EoL) End of Life activities refer to activities related to i) re-use or recycling; ii) waste treatment, and iii) disposal. In particular, during high energy processes, the release of nano-objects may not be excluded. The required research priorities on exposure, transportation and life cycle include: - Mechanistic understanding of processes determining the release of ENM. - Understanding the transformation and transport of ENM. - Understanding workplace, consumer and environmental exposure.
http://www.nanosafetycluster.eu ECHA Workshop 2014-10-23 M. Stintz: Characterisation of nanomaterial release during their lifecycle 32
General processes and areas of possible release and exposure:
NanoSafetyCluster Study 2013
Faculty of Mechanical Engineering Institute of Process Engineering and Environmental Technology Research Group Mechanical Process Engineering
