GEOC 164 |
| Stephen B. Johnson, Tae Hyun Yoon, and Gordon E. Brown Jr. Department of Geological & Environmental Sciences, Stanford University, Building 320, 450 Serra Mall, Stanford, CA 94305-2115 |
| Macromolecular organic materials such as humic acids are prevalent in a wide range of environments, and are strongly associated with mineral particles under environmentally relevant pH conditions. A variety of past studies of humic acid adsorption on mineral surfaces have treated humate adsorption as an inner-sphere process, that is, one involving formation of a direct bond between the surface cations and (predominantly) the humate carboxyl groups. To date, however, few spectroscopic studies have been performed to directly probe the nature of the interaction between humic acids and mineral surfaces. In this study, the adsorption of a reference humic acid on goethite has been probed using in situ ATR-FTIR spectroscopy and macroscopic adsorption experiments. Measurements have been performed over a wide range of humic acid concentrations and pH conditions. Based on these results, the nature of the dominant humate – goethite interaction, and its implications for mineral dissolution processes, have been determined. |
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Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
1:20 PM-5:40 PM, Wednesday, March 31, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |