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SORPTION OF ARSENATE AND ARSENITE ON RUO2 X H2O: ANALYSIS OF SORBED PHASE OXIDATION STATE BY XANES IN ADVANCED PHOTON SOURCE ACTIVITY REPORT 2002
Citation:
Impellitteri**, C A., K G. Scheckel*, AND J A. Ryan*. SORPTION OF ARSENATE AND ARSENITE ON RUO2 X H2O: ANALYSIS OF SORBED PHASE OXIDATION STATE BY XANES IN ADVANCED PHOTON SOURCE ACTIVITY REPORT 2002. Argonne National Laboratory, Argonne, IL, 2003.
Description:
The sorption reactions of arsenate (As(V)) and arsenite (As(III)) on RuO2 x H2O were examined by X-ray Absorption Near Edge Spectroscopy (XANES) to elucidate the solid state speciation of sorbed As. At all pH values studied (pH 4-8), RuO2 x H2O showed a high affinity for As regardless of the initial As species present. Sorption was higher at all pH values when the initial As species was As(III). Oxidation of As(III) (250 mg/L solution) to As(V) was virtually complete (98-100%) within 5 seconds. XANES results showed the presence of only As(V) on the RuO2 x H2O regardless of the initial As oxidation state. There was no change in the oxidation state for 4 weeks in both oxic and anoxic environments. It is speculated that changes in the RuO2 x H2O structure, due to oxidation reactions, caused the higher total As sorption capacity when As(III) was the initial species.