GEOC 99 |
| The effect of a strong oxidant, HOCl/OCl-, on the dissolution of Cr(III)–muscovite containing 0.5 ± 0.2 mol % of Cr(III) was investigated under flow–through conditions. In the absence of the oxidant at pH 2 and 9, Al was preferentially released over Cr likely due to the highly inert Cr(III)–O bonds. In its presence, release of Cr was accelerated at pH 9 by a factor of 3.7 but decreased slightly at pH 2. The acceleration at pH 9 may result from formation of soluble chromate by the oxidant, whereas the deceleration at pH 2 coincided with sorption of Cr(VI) to fuchsite that occurred only at pH < 2.5. Lower release rates of Al and Si observed in the presence of the oxidant than its absence at both pH's may be due indirectly to a charge imbalance in the framework, resulting from the preferential release of Cr(III) by oxidation. |
|
Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
1:30 PM-4:45 PM, Tuesday, 12 September 2006 Moscone Center -- Room 256, Oral
Sci-Mix
Division of Geochemistry |