GEOC 86 |
| Birnessites are among the most abundant of nature's nanoparticles. Birnessites are enriched in trace metals (TMs) by many orders of magnitude relative to crustal averages, and have long been recognized as the 'scavengers of the environment'. A key problem in environmental geochemistry is to determine how TMs are structurally bound to mineral species from this family. Important progress has been made recently by the synergistic application of X-ray fluorescence, diffraction and absorption techniques at micron-scale lateral resolution to nanocrystalline birnessites coupled with determination of structural and chemical defects (stacking faults, ionic vacancies and occupancies, impurity sites, stoichiometry) of these birnessites by modelling of X-ray scattering profiles. This new hybridization of experimental and modelling approaches to the characterization of birnessites will be illustrated with examples we are currently investigating. |
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Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
8:15 AM-11:55 AM, Tuesday, 12 September 2006 Moscone Center -- Room 256, Oral
Division of Geochemistry |