GEOC 30 |
| Natural organic matter (NOM) exists as dissolved molecules, solid particles, or mineral coatings, which can all bind aqueous metals. When NOM coats minerals, its sorption capacity and the underlying solid's reactivity may change. To characterize reactivity changes we are investigating the structure of dissolved NOM with and without barium at the mica(001)-water interface using in-situ X-ray reflectivity. When 100 ppm Elliott Soil Fulvic Acid II (FA) mixed with 0.005 m BaCl2 was added to mica, the distribution and occupancy of interfacial barium were not significantly different from those in 0.005 m BaCl2 alone. However, when FA was added to mica before BaCl2, preliminary results suggest that more Ba resided over a broader region of the sorbed FA layer. FA thickness varied from 8 to 12 Angstroms, with the higher value occurring when barium was present. Funded by Office of Science, Geoscience Research Program, US-DOE under grant FG02-02ER15364 and contract W-31-109-ENG-38. |
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Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
1:30 PM-5:10 PM, Sunday, 10 September 2006 Moscone Center -- Room 256, Oral
Division of Geochemistry |