Slides presented at the workshop Safe-fy-Design: a joint event of TU Delft and the Dutch Ministry of Infrastructure and Water Management.

1. Safety of Nanomaterials
J. Ruud van Ommen, ChemE, TU Delft
Workshop Safe by Design
5 October 2018

2. Nanomaterials
o Why nano?
o Potential risks
o Pathways for safe design
Disclaimer: these slides are meant to reflect thoughts
and start a discussion, not to present a finished study

3. But why nano?

4. Nano-objects: 1 or more dimensions 1 – 100 nm
Nanoparticle Nanotube Nanosheet
5x107 smaller 5x107 smaller
Nanoparticle

5. Nano-objects: 1 or more dimensions 1 – 100 nm
Nanoparticle
1 gram: 1x1018 nanoparticles
300 m2 surface area
5x107 smaller 5x107 smaller
Nanoparticle

6. CO+O2CO2
Kim et al., N Engl J Med 2010
Size
[nm]
Tmelt[K]
Diam. [nm]
Diam. [nm]
Cat. activity [-]
Bell,
Science 2003
Schoen et al., J Mat Chem 2009
Melting point reduction
Color change
Scale of life
From commons.wikimedia.org
Gold: Macro to Nano

7. or
Nanoparticle Nanotube Nanosheet
Nanostructured particles:
even more exciting properties!
Combine
multiple
materials
Nanostructured particles

8. To come to real solutions,
large amounts are needed!
1g ~1018 nanoparticles

9. 1900
2000
2000Bulk chemicals
Nanostructured materials
*Eckelman et al., J. Ind. Ecol (2008)

10. Reduce the use of critical materials
McElroy et al., Green Chem 2015
Time till depletion
of known reserves
1. Use nanostructures as alternatives (e.g., replace Indium in ITO by graphene)
2. Use critical materials as optimal as possible (e.g., Platinum)

11. Fuel cell in person car: ~30 g platinum
Global Pt production: 180 ton/year
Example: optimum use of platinum
Max. 6 mln cars/year can be supplied
30 g Pt <1 g Pt?

12. Potential risks

13. Nanoparticle interactions with cells
Nel et al., Science 311 (2006) 622
Kim et al., N Engl J Med 2010
Size
[nm]

14. Mechanistic injury pathways
Nel et al., Acc.
Chem. Res. 46
(2012) 607

15. Zhou et al. J.Controlled Release 270 (2018) 290
Crossing the blood-brain barrier

16. Oxidative stress model
Nel et al.,
Science 311
(2006) 622
Amount of oxidative stress determines reaction in the cell.

17. Safe by design
• Shape selection
• Materials selection
• Coating
• Agglomeration
• Embedding

18. Manufacturers, scientists and shipbuilders
are commonly exposed to CNTs
Worldwide CNT usage
in industry (tons)
2012
2022
(projected)
1969
2014
UK deaths from
asbestos
Shape selection
Nanoparticles might be less problematic than nanotubes/nanofibers
www.technologynetworks.com

19. Manufacturers, scientists and shipbuilders
are commonly exposed to CNTs
Worldwide CNT usage
in industry (tons)
2012
2022
(projected)
1969
2014
UK deaths from
asbestos
Shape selection
Nanoparticles might be less problematic than nanotubes/nanofibers
www.technologynetworks.com

20. Materials selection
Zhang et al., ACS Nano 6 (2012) 4349

21. Coating
researchscholarinfo.blogspot.com
Risks: Skin penetration
Environmental
Solution: Coating
Example:
Sunscreen
10 nm
Al2O3 on TiO2
Valdesueiro et al.,
Materials 8 (2015) 1249

22. Clustering
Aerosil – Fumed silica; technical overview by Evonik
van Ommen et al., J. Nanopart. Res. 12 (2012) 737
4 mm
complex
agglomerates
simple
agglomerates
aggregates

23. Fabre, Clemente et al., Environ. Sci.: Nano 4 (2017) 670
van Ommen et al., J. Nanopart. Res. 12 (2012) 737
4 mm
complex
agglomerates
simple
agglomerates
aggregates
Clustering

24. Embedding
Example: mixing nanosilica in rubber for energy-efficient tyres
project: Univ. of Twente (Dierkes) & TU Delft (van Ommen)

25. Embedding
Possible solutions
Proper choice of material,
e.g. silica or carbon
Concentration so low that it
become negligible
Challenges
Materials might become
hard to separate
Recovering valuable
materials hard when too
much diluted

26. • MSc ChemE:
– Core course: Product & Process Design
– Elective course: Nanoparticle Technology
• PDEng programme Chemical Product Design
Education

27. Conclusions
o Nanomaterials can contribute to solving grand challenges
(energy, water, health, …)
o Health and environmental risks are not yet fully clear
o Proper design can help to minimize the risks
j.r.vanommen@tudelft.nl