Simultaneous Reduction of Arsenic(V) and Uranium(VI) by Mackinawite: Role of Uranyl Arsenate Precipitate Formation
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- 作者：Lyndsay D. Troyer ; Yuanzhi Tang ; Thomas Borch
- 刊名：Environmental Science & Technology
- 出版年：2014
- 出版时间：December 16, 2014
- 年：2014
- 卷：48
- 期：24
- 页码：14326-14334
- 全文大小：329K
- ISSN：1520-5851
文摘
Uranium (U) and arsenic (As) often occur together naturally and, as a result, can be co-contaminants at sites of uranium mining and processing, yet few studies have examined the simultaneous redox dynamics of U and As. This study examines the influence of arsenate (As(V)) on the reduction of uranyl (U(VI)) by the redox-active mineral mackinawite (FeS). As(V) was added to systems containing 47 or 470 渭M U(VI) at concentrations ranging from 0 to 640 渭M. In the absence of As(V), U was completely removed from solution and fully reduced to nano-uraninite (nano-UO2). While the addition of As(V) did not reduce U uptake, at As(V) concentrations above 320 渭M, the reduction of U(VI) was limited due to the formation of a tr枚gerite-like uranyl arsenate precipitate. The presence of U also significantly inhibited As(V) reduction. While less U(VI) reduction to nano-UO2 may take place in systems with high As(V) concentrations, formation of tr枚gerite-like mineral phases may be an acceptable reclamation end point due to their high stability under oxic conditions.