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CNRS 
Du stiness of airborne functional nanomaterials with tailored size, shape and surface chemistry: evaluation and potential solutions
Université Pierre et Marie Curie, Paris
Chimie de la Matière Condensée de Paris
Nanotechnology Physical Chemistry Ecotoxicology and Pollution 
Full Description:

Please note, this offer is for Chinese students ONLY. Please read about the application details at the link below. Funding IS NOT granted at the moment. Selection will occur on CV.

http://candidature.sorbonne-universites.fr/images/emundus/prog_CSC_doctorants_%C3%A9tape_2_ENGLISH_7d813.pdf

 

Summary

Nanotechnologies have a strong economic impact and present a societal challenge. During the last twenty years, technological advances in nanomaterials have allowed the development of new applications in fields such as medicine (for therapeutic and diagnostic purposes), environment (water treatment), food (membranes for purification) and industry (electronics, energy). However, the scientific knowledge on health and environmental risks indicated that nano-objects have potentially adverse health effects on exposed workers and the general population through potential routes of exposure like ingestion, epidermal absorption, and, above all, inhalation[i] of airborne particles – the most predominant and dangerous form in the workplace. Potential release of nanoparticles in air is important to consider in order to design a potential industrial processes,[ii] since accidental release can occur at any time through the nano-powder life cycle, such as the manufacturing, handling, use and compaction steps. A European regulatory framework for nano-objects is now emerging and it is essentially focused on end-products containing manufactured nanomaterials (such as cosmetics, novel foods). While some regulations concerning airborne particles exist (e.g.: particulate matter released from vehicle emission in Europe), none of them actually cover specifically manufactured airborne nano-objects. The physico-chemical parameters that characterize the nano-objects, such as particle number concentration, size distribution, surface composition are crucial and under actual consideration for future health-based legislation for workplaces survey and industrial processes control.[iii] Therefore, there is a clear need to focus on exposure assessments of nano-objects. In a recent work, we have characterized the physical-chemistry properties of the most important manufactured and engineered nanomaterials in the industry,[iv] titanium dioxide (TiO2) and silicon dioxide (SiO2), directly provided by the manufacturers within the framework of the NANOGENOTOX EU Project.[v],[vi] In that study, among others, we have demonstrated that the dustiness of TiO2 nanoparticles strongly
varies as a function of their morphology and crystal structure. In particular, we have found that the mass specific release (number of particle per kg) of TiO2 (rutile) is 10000 higher than TiO2 (anatase), where the main differences are the crystal structure and aspect ratio (0.9 for anatase versus 0.62 for rutile). More interestingly, a mixture of 90% anatase and 10% rutile and for a comparable average aspect ratio (0.8), the mass specific release is still 1000 higher than pure rutile!6

In terms of the relationship between structure/morphology and in-vivo toxicity, recent works start to appear on the skin penetration pathways[vii] and toxicokinetics in blood stream, [viii] for instance. However, a lot of work mainly concentrates on silica and titania. This is justified by the fact that, according to the EU commission, the global quantity of nanomaterials annually marketed was estimated to be around 11.5 million tons in 2010 among which 1.5 million and 10 000 tons synthetic amorphous silica and titanium dioxide respectively.[ix] Nevertheless, if compared to the
actual development of nanomaterials in research laboratories, SiO2 and TiO2 can definitely be considered as “primitive” in terms of their complexity. In fact, an extensive variety of materials are actually synthesized and are of potential interest in fields as wide as catalysis, drug delivery, chromatography, fillers, antimicrobial agents, energy, etc… and many of these material are more and more obtained in the form of dried powders. An example for all, new trends in the field of anode materials for lithium-ion batteries is to use spray drying as a preferred synthetic pathway, as shown by the recent works on the synthesis of silicon–carbon composite particles, where silicon
nanoparticles are embedded in porous carbon particles.[x] Beside the richness in terms of chemical formula (metal, metal oxides, organic, carbon, organic-inorganic hybrids…), it is possible to control the shape (e.g., spheres, rods, star-shaped, raspberry, mass fractals, core-shell, layered, tetrapods, etc...) and surface chemistry (hydrophilic, hydrophobic, charged, complexing, etc...). Most, if not all, of these nanomaterials need to be assessed and the goal of this project is double: 1) to evaluate their dispersion in air (dustiness) as a function of their chemical formula,  structure, morphology and surface chemistry;  2) identify possible pathways to limit the airborne dustiness.

[i] [a] G. Oberdörster, Pulmonary effects of inhaled ultrafine particles, Int. Arch. Occup. Environ. Health 74 (2001) 1–8; [b] A.D. Maynard, E.D. Kuempel, Airborne nanostructured particles and occupational health, J. Nanopart. Res. 7 (2005) 587–614; [c] O. Witschger, J.F. Fabriès, Particules ultra-fines et santé au travail. 1 — Caractérisation des effets potentiels sur la santé, Hyg. Sécur. Trav. 199 (2005) 21–35 ; [d] A. Nel, T. Xia, L. Madler, N. Li, Toxic potential of materials at the nanolevel, Science 311 (2006) 622–627; [e] Agence Française de Sécurité Sanitaire de l'Environnement et du Travail AFSSET, Les nanomatériaux, effets sur la santé de l'homme et de l'environnement, Agence Française de Sécurité Sanitaire de l'environnement et du Travail, 2006 ; [f] B. Hervé-Bazin, Nanoparticles: A Major Challenge for Occupational Health? 1st ed. Les Ulis EDP Sciences, 2007.

[ii] F. Hamelmann, E. Schmidt, Methods for estimating the dustiness of industrial powders — a review, KONA 21 (2003) 7–18.

[iii] ISO/TR 13014, Nanotechnologies — Guidance on Physico-chemical Characterization of Engineered Nanoscale Materials for Toxicologic Assessment, 2012.

[iv] Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail ANSES report, Développement d'un outil de gestion graduée des risques spécifique au cas des nanomatériaux (control banding), http://www.anses.fr/sites/default/files/documents/AP2008sa0407.pdf 2011

[v] http://www.nanogenotox.eu

[vi] Motzkus C., F. Gaie-Levrel, Patrick Ausset, Michel Maille, Baccile N., Vaslin-Reimann S., Idrac J., Oster D., Fischer N. and Macé T., Impact of batches variability on physicochemical properties of manufactured TiO2 and SiO2 nanopowders, Powder Technol., 2014, 267, 39-53

[vii] H. I. Labouta, L. K. El-Khordagui, T. Krausc, M. Schneider Mechanism and determinants of nanoparticle penetration through human skin, Nanoscale, 2011,3, 4989-4999 Hagar I. Labouta,ab   Labiba K. El-Khordagui,b   Tobias Krausc and   Marc Schneider*a

[viii] S. Laurent, D. Forge, M. Port, A. Roch, C. Robic, L. Vander Elst, R.N. Muller, Magnetic iron oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical characterizations, and biological applications, Chem. Rev. 108 (2008) 2064–2110.

[ix] E. Gaffet, D. Block, B. Gouget, N. Herlin-Boime, B. Honnert, A. Lombard,M. Riediker, F. Tardif, Nanomaterials and occupational safety report, AFSSET report, http://www.afssa.fr/ET/DocumentsET/08_07_ED_nanomateriaux_2_rapport_EV_opti.pdf 2008.

[x] [a] D. Soo Jung, T. Hoon Hwang, S. Bin Park, J. Wook Choi, Spray Drying Method for Large-Scale and High-Performance Silicon Negative Electrodes in Li-Ion Batteries, Nano Lett., 2013, 13, 2092–2097; [b] L. Gan, H. Guo, Z. Wang, X. Li, W. Peng, J. Wang, S. Huang, M. Su, A facile synthesis of graphite/silicon/graphene spherical composite anode for lithium-ion batteries, Electrochimica Acta 2013, 104, 117–123

 

 

 

 

 



Posted on: 02 February 2015Deadline to apply: 28 February 2015Start Date: 01 October 2015 Duration: 36 months
The Fund category is Not Defined and the salary is 15-20k€ annual gross
Doctoral School is Materials physics and chemistry in the Ile-de-France Region.

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