Project 6: Nanomaterial Design for Environmental Health and Safety

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New nanomaterials offer promise as enabling components in next-generation environmental technologies, but may also pose health risks of their own through unintended exposure. Project 6 uses modern methods of nanosynthesis to create, characterize, and formulate new materials for study of both their implications and applications to environmental health and safety. In the initial funding period, a panel of nanomaterial and nanostructured material sorbents was created and evaluated for capture of vapor phase mercury. Ozone-treated carbon and nanoscale Ag, Cu, Ni, S, and Se were shown to have much higher adsorption capacities than conventional versions of the same materials, and one nanosorbent formulation (unstabilized, amorphous nano-selenium) had fifty-fold higher activity than any sorbent commercially available today. The renewal will investigate the detailed mechanisms of Hg/nanomaterial reactions with emphasis on creating new technologies for aqueous-phase mercury removal in collaboration with Project 5 and new technologies for managing the mercury released from fluorescent lamps that break during handling, use, or end-of-life disposal. In the area of nanotechnology implications, techniques were developed to quantify metal bioavailability and identify the role of hydrophobic surface area in the toxicity of carbon nanotubes. Research was also carried out on safer nanomaterial formulations including new purification protocols that detoxify nanotubes through targeted removal of bioavailable metal, functionalization of nanotubes to suppress folate adsorption that inhibits cell proliferation, and the use of TPGS as a new anti-oxidant surfactant for "green" aqueous nanotube processing, all in close collaboration with Project 2. In the next funding period, we hypothesize that the biological response to nanoscale nickel, nickel oxide, chromate, and Ni/Y-containing carbon nanotubes will depend on size, surface state, and specific formulation. Alternative formulations will be prepared through annealing, oxidation, purification, and covalent and noncovalent surface modification, and the behavior of the materials will be studied in complex biological and environmental fluid phase simulants. A joint goal of Projects 2, 4, and 6 is to understand the materials and molecular bases for nanotoxicity through iterative nanomaterial formulation and biological testing. It is anticipated that this iterative and collaborative process will lead to nanomaterial structure/activity relations and general rules for safe nanomaterial design.