HR: 16:30h
AN: NS44A-05    [Abstracts]
TI: The colloid behavior of nanoparticles in aqueous environments
AU: * Gilbert, B
EM: BGilbert@lbl.gov
AF: Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 United States
AB: Microbial metabolism-driven biomineralization is a productive source of nanoscale oxide and sulfide minerals in subsurface environments. In common with synthetic nanoparticles, biogenic nanoparticles can possess modified surface and interior structures, and confined electronic structure. The lifetime and geochemical behavior of nanoparticles in the environment are poorly understood, but it is anticipated that their fate and mobility are strongly affected by their colloid properties. Electron microscopy indicates nanoparticles to be gregarious, readily clustering to form nanoporous aggregates. Such aggregate formation reduces the nanoparticle surface area that is accessible to aqueous species, and permits growth via oriented aggregation. Nanoparticle transport properties are dependent on aggregate structure, which thus is a significant factor for the effectiveness of contaminant immobilization through bioremediation. We present synchrotron- and laboratory-based studies of the colloid behavior of synthetic nanoparticles under environmentally-relevant conditions and describe approaches for the quantitative description of aggregate structure.
DE: 1045 Low-temperature geochemistry
DE: 3250 Fractals and multifractals
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
DE: 4805 Biogeochemical cycles (1615)
DE: 4809 Colloids
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly