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Meeting in New Orleans: An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media
Citation:
LOUX, N. T. AND N. SAVAGE. Meeting in New Orleans: An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media. Presented at American Chemical Society National Meeting, New Orleans, LA, April 06 - 10, 2008.
Impact/Purpose:
Task 12553 focus is on producing technical products of increasing utility to EPA by incorporating recent findings of the professional research community into existing EPA tools, and by advancing state-or-the-science in a number of areas related to geochemical and interfacial phenomena significant to assessing environmental contaminant fate and transport. One aspect of this task is devoted to developing proof-of-concept and/or research models in areas relevant to EPA's mission.
Description:
This work assesses potential aqueous environmental metal oxide nanomaterial self-aggregation through the application of recent developments in surface complexation theory with historical DLVO procedures. Findings include: 1) nanomaterials with a Hamaker constant as large as 1E-19 J (and an absolute surface potential < 25 mV) will likely aggregate in most environmental aquatic media, 2) natural organic matter coatings may render metal oxide nanomaterials less likely to aggregate in aquatic media, 3) nanomaterials in aqueous suspension will likely have an absolute surface potential less than their micron-sized counterparts of the same composition, and 4) robust diffuse layer model databases of intrinsic surface site reactivity constants with multivalent aqueous environmental ions will need to be developed to provide accurate estimates of the surface potential of nanoparticles suspended in aqueous environmental systems.