GEOC 90 |
| Christopher S. Kim1, Jillian F. Banfield2, and Glenn A. Waychunas1. (1) Earth Sciences Division, Lawrence Berkeley National Laboratory, MS 70R0108B, 1 Cyclotron Road, Berkeley, CA 94720, (2) Departments of Earth and Planetary Science and Department of Environmental Science, Policy, and Management, University of California- Berkeley, 307 McCone Hall, Berkeley, CA 94720 |
| Of the many nanoscale mineral phases present in the environment, iron (oxy)hydroxides are among the most common and most reactive in terms of metal contaminant uptake. However, the degree and mode of metal uptake onto nanoparticles as a function of particle size are not well understood. Goethite batches of 10, 25, and 75 nm in effective diameter were synthesized for use in uptake experiments featuring As(V), Cu(II), Hg(II), and Zn(II), metal(loid) contaminants associated with acid mine drainage systems. EXAFS spectroscopy analysis indicates changes in metal speciation on the 10-nm particles compared with the 25- and 75-nm particles. Such differences may be due to changing proportions of binding sites (e.g. edges, corners) and particle morphology evolution from oblong (10-nm particles) to more acicular (25- and 75-nm particles) as particle size increases. Additionally, macroscopic uptake measurements indicate that the degree of uptake varies with particle size, independent of surface area effects. |
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Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
1:00 PM-5:50 PM, Tuesday, March 30, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |