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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
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.
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.
Record Details:Record Type: DOCUMENT (SUMMARY)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
WATER SUPPLY AND WATER RESOURCES DIVISION
WATER QUALITY MANAGEMENT BRANCH