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Coprecipitation of Arsenate and Arsenite with Green Rust Minerals
Citation:
Holder, C. AND C. SU. Coprecipitation of Arsenate and Arsenite with Green Rust Minerals. Presented at The Oklahoma Research Day at the University of Central Oklahoma, Edmond, OK, October 26, 2007.
Impact/Purpose:
To present information at the Oklahoma Research Day .
Description:
The objectives of this experiment were to evaluate the extent and nature of arsenic co-precipitation with green rusts and to examine the influence of arsenic incorporation on the mineralogy of formed solid phases. Stoichiometric green rusts were obtained by coprecipitation of ferrous and ferric ions in both carbonate and sulfate-containing solutions spiked with arsenate or arsenite. The batch tests showed that As removal ranged from 90-100% by carbonate green rust with As(V) and As(III). We observed partial oxidation of As(III) in the system to As(V) when As(III) was the added As species. The oxidation of As(III) is advantageous because As(V) is less toxic and less mobile than As(III) in the environment. We observed sulfate green rust form at 0.05 M As(III) at a pH of 6.34. We observed that other iron oxides removed both As(V) and As(III) efficiently.