GEOC 166 |
| Paul Fenter1, Changyong Park1, Likwan Cheng1, Zhan Zhang2, and Neil C. Sturchio3. (1) Environmental Research Division, Argonne National Laboratory, Argonne, IL 60439, (2) Northwestern University, 2225 N. Campus Drive, Evanston, IL 60208, (3) University of Illinois at Chicago and Argonne National Laboratory, Chicago, IL 60607 |
| The chemical weathering of silicate minerals has been extensively studied, but insights into the dissolution mechanisms have been obscured by the complexities associated with traditional chemical methods of probing mineral dissolution. We describe the use of x-ray reflectivity to probe the dissolution of orthoclase (KAlSi3O8). The systematic variation of dissolution kinetics was measured as a function of temperature (31.5°C £ T £ 76°C) and pH (0 £ pH £ 3.5). These measurements allow for precise determination of dissolution rates due to the known, crystallographically controlled, reactive site density on freshly-cleaved (001) surfaces. The results will be discussed in the context of a proton promoted dissolution mechanism as modeled using surface complexation models. |
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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 |