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Environmental Risks for the Metal Nanopowders

#4029


Scientific Aspects of Hazard-Based Classification of Metal Nanopowders, Considering Fire, Explosion and Toxic Release Hazards

Tech Area / Field

  • CHE-SAS/Safety and Security/Chemistry
  • BIO-SFS/Biosafety and BioSecurity/Biotechnology
  • ENV-DMT/Dangerous Materials Transportation /Environment
  • ENV-EHS/Environmental Health and Safety/Environment
  • ENV-MRA/Modelling and Risk Assessment/Environment

Status
3 Approved without Funding

Registration date
05.02.2010

Leading Institute
Institute of problems of chemical-energetic technologies Siberian Branch of Russian Academy of Sciences, Russia, Altay reg., Biysk

Supporting institutes

  • Tomsk State University, Russia, Tomsk reg., Tomsk\nInstitute of Physics of Strength and Materials Technology, Russia, Tomsk reg., Tomsk

Collaborators

  • Fraunhofer Institute Chemische Technologie, Germany, Pfinztal\nJAXA / Institute of Space and Astronautical Science, Japan, Kanagawa\nDefence Research and Development Canada, Canada, QC, Valcartier\nSNPE Matériaux Energétiques, France, Paris\nMinistry of Defense / DSTL, UK, Kent, Sevenoaks\nEuropean Space Agency / Directorate of Human Spaceflight, The Netherlands, Noordwijk\nMACH I Inc., USA, PA, King of Prussia\nPolitecnico di Milano / Space Propulsion Laboratory, Italy, Milan

Project summary

The problem of safety of nanotechnology as a whole, as well as assessment of risks of nanopowder production and use in particular, considering nanopowders as fire/explosion hazardous environments, is fundamental. Nanoparticles of metals are very reactive, this cannot be described by extrapolation of size effect solely. Nanoparticles have the following specific properties, which are not observed for larger particles: self-ignition and thermal explosion in the air and other active gases; acute decrease of ignition temperature and increase of combustion speed; probability of detonation-type distribution of ignition; ignition initiated by ignition sources which are non-specific for metals, e.g. static charges.

No fundamental researches which would make it possible to assess all risks connected with nanosized materials as fire/explosion hazardous environments were conducted at present. However the use of nanopowders requires the risks connected with pyrophoricity of nanoparticles to be assessed and taken into account at the stage of process engineering.

The Project involves a comprehensive investigation of behavior of metal nanoparticles under the influence of external factors from a safety point of view – release of inflammable gases, ignition temperature, combustion rate, possible self-ignition, reactions leading to self-heating and explosion.

As new nanopowder production facilities are being created, society faces the problem of studying toxic properties of metal nanoparticles, the properties which are not observed in comparatively coarse particles. Nanoparticles as a component of an aerosol, unlike coarse fractions, probably have more profound pathogenic effects, than nanopowders of asbestos, quartz and other materials. Nanoparticles have larger surface area per unit weight, thus they can cause severe inflammatory reactions (e.g. in lung tissue). Apart from that, the size of nanoparticles gives them an ability to penetrate into the brain, liver and other vital organs. Thus the toxicology of nanoparticles cannot be limited to study of the impact on respiratory system solely, but it has to analyze the impact on brain, blood, liver and skin.

The goals of the Project are production and characterization of metal nanoparticles, scientific study of their fire, explosive and toxic properties, elaboration of criteria and classification of metal nanoparticles by hazard class, development of laboratory analytical complex for certification of nanopowders for use in production, storage and transportation technologies.

In the framework of this Project combustion and oxidation parameters of nanoparticles as a separate substance and as a part of a mixture will be a subject of detailed study using workbenches of IPChET and ISPMS SB RAS. Laboratory tests of electrostatic sensitivity of nanoparticles and their mixtures with various samples of explosive substances will be carried out in Tomsk State University at the same time. Mathematical models of abovementioned processes will be developed. A comprehensive study of toxicity of nanoparticles will be carried out by R&D Institute of Biology and Biophysics (Tomsk State University).

The following tasks are to be completed in order to achieve the Project’s goal:

  • Production of lots of Al, Ti, Fe, Cu, Ni, Zn nanopowders by electric explosion of wire (EEW) - method and their characterization: particle size distribution, metal phase and specific surface area evaluation;
  • Study of oxidation kinetics of metal nanopowders in relation to heating characteristics;
  • Study of short-pulse ignition process with low-calorie ignition source as well as study of electrostatic charge ignition processes of nanoparticles of Ti, Fe, Cu, Ni and Zn.
  • Measurement of flame propagation rate for various types of nanopowders with different passivation degree (modification of surface behavior and metal phase content), particle size and specific surface area;
  • Determination of intensity of hydrogen generation upon interaction of Al and Zn and other metal nanoparticles with water in relation to metal phase content, particle size and specific surface area;
  • Elaboration of fire hazard criteria, classification of investigated nanopowders by hazard class.
  • Investigation of mechanisms of influence of metal nanoparticles on living organisms at molecular, cytogenetic, physiological and behavioral levels. Elaboration of physiologically validated criteria of environmental threats of metal nanopowders.

Project members and their responsibilities

Project authors have the knowledge and equipment necessary for independent research. The results of the Project will be up to the world standards considering extensive experience of Project proponents in the field of nanotechnology and simulation of processes of ignition and combustion of high energy materials (HEM) under various conditions.

Each team will perform a specific research providing other teams with the results to be used for solving their tasks. The combination of activity of different teams will ensure successful implementation of the Project. In particular,

  • Institute for problems of chemical and energetic technologies (Biysk) – developer of technology and producer of metallic HEMs. Institute experts have extensive experience in simulation of ignition, combustion and explosion of HEMs, as well as in calculation of thermal and concentration fields and evolution of propagation of aerosol clouds produced by combustion and explosion.
  • Tomsk State University (Tomsk) has considerable experience in the field of characterization and passivation of nanopowders and development of encapsulation methods. R&D Institute for Biology and Biophysics (TSU) has considerable experience in the field of investigation of impact of potentially toxic components of aerosols (nanopowder suspension and products of their detonation or combustion) and estimation of potential environmental risks.
  • Institute of Strength Physics and Material Science SB RAS (Tomsk) is one of the developers of technology of metal nanopowder production by EEW-method. The institute produces metal nanopowders in industrial lots. Investigation of fire hazard of Al, Cu, Ni, Zn and Fe nanopowders are carried out here.

Expected outcome

The following results are expected as a result of Project activity:

  1. Creation of a laboratory workbench for investigation of fire/explosion hazard of metal nanopowders, including the chamber for pre-spraying of nanomaterials in a certain atmosphere for investigation of fire/explosion hazard of metal nanopowder air mixtures;
  2. Development of the methods of investigation of fire/explosion hazard of metals as nanopowders and particle clouds containing metal nanoparticles.
  3. Production of lots of Al, Ti, Fe, Cu, Ni, Zn nanopowders by EEW-method and their characterization: particle size distribution, metal phase content and specific surface area.
  4. Investigation of short-pulse ignition process of metal nanopowders with low-calorie ignition source as well as ignition and detonation initiated by an electro-static charge.
  5. Measurement of flame propagation rate for various types of nanopowders with different passivation degree and encapsulation methods. Lots of Al, Ti, Cu, Zn, Fe, Ni, W nanopowders (with average particle size 50-100nm) passivated in different environmental conditions are required to be produced for this purpose; a procedure of passivation and micro-encapsulation of nanoparticles with organic layers for nanopowders of the most pyroforic materials (Al, Ti, Fe) is also required to be developed.
  6. Determination of intensity of hydrogen generation upon interaction of various types of nanoparticles with water.
  7. Elaboration of fire hazard criteria, classification of nanopowders by hazard class.
    • by flammability groups;
    • by inflammability of metal nanopowders in the course of short-pulse ignition process with low-calorie ignition source.
    • by flame propagation rate;
    • by intensity of gas generation upon interaction of metal nanopowders with water;
    • by hazard class.
  8. Investigation of mechanisms of influence of metal nanoparticles on living organisms at molecular, cytogenetic, ontogenetic and physiological levels. Elaboration of physiologically validated criteria of environmental threats of metal nanopowders.

The Project fully conforms to goals and objectives of ISTC. The proposed program will enable Russian "weapon" scientists to use their knowledge and experience in the field of solving international problems of disarmament and environment protection.

Cooperation with foreign collaborators will facilitate integration of Russian "weapon" experts into the international scientific community, this will enable further use of obtained results for creation of laboratory analytical complex for certification of nanopowders for use in production, storage and transportation technologies.

New scientific knowledge and recommendations, worked out in the course of Project implementation will promote development of means and approaches to minimization of economic and environmental risks connected with production, storage and transportation of nanoparticles and nanomaterials.

Collaborators of the Project include leading world organizations and experts in the field of nanotechnology. Cooperation with foreign collaborators will promote integration of Russian "weapon" experts into the international scientific community, this will enable more effective dissemination and use of research results on scientific assurance of safety for production, storage and transportation of nanopowders.


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