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ARSENATE REDUCTION BY ORGANIC COMPOUNDS
Citation:
Smieja, J. AND R W. Puls*. ARSENATE REDUCTION BY ORGANIC COMPOUNDS. Presented at 223rd Natl. Mtg. of the American Chemical Soc, Orlando, FL, 04/07-11/2002.
Description:
Arsenic is found in a variety of forms and oxidation states depending on soil pH and redox conditions. Under oxic conditions, arsenate is thermodynamically favored but arsenite, the more toxic and mobile form of arsenic, is favored under mildly reducing conditions. In many soils, organic compounds are the dominant reductants and play a critical role in metal speciation. Since the most abundant functional groups in natural organic matter are carboxylate, carbonyl alcoholate, and phenolate groups, organic molecules possessing alpha-hydroxy carboxylate or phenolate functional groups are used to model soil organic matter. These model compounds are known to reduce manganese (III, IV), iron(III), and chromium(VI), and based on thermodynamic considerations, are potential reductants for arsenate. Here we report the results of a laboratory study designed to explore rates of arsenate reduction by these model compounds in the presence and absence of a variety of metal oxide catalysts.