- Title
- Simultaneous redox conversion of chromium(VI) and arsenic(III) under acidic conditions
- Creator
- Wang, Zhaohui; Bush, Richard; Sullivan, Leigh; Liu, Jianshe
- Date
- 2013
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99750
- Identifier
- vital:10416
- Identifier
-
https://doi.org/10.1021/es400547p
- Identifier
- ISSN:0013-936X
- Abstract
- Arsenic and chromium are often abundant constituents of acid mine drainage (AMD) and are most harmful as arsenite (As(III)) and hexavalent (Cr(VI)). To simultaneously change their oxidation state from As(III) to As(V), and Cr(VI) to Cr(III), is a potentially effective and attractive strategy for environmental remediation. The coabundance of As(III) and Cr(VI) in natural environments indicates their negligible direct interaction. The addition of H 2O2 enables and greatly accelerates the simultaneous oxidation of As(III) and reduction of Cr(VI). These reactions are further enhanced at acidic pH and higher concentrations of Cr(VI). However, the presence of ligands (i.e., oxalate, citrate, pyrophosphate) greatly retards the oxidation of As(III), even though it enhances the reduction of Cr(VI). To explain these results we propose a reaction mechanism where Cr(VI) is primarily reduced to Cr(III) by H2O2, via the intermediate tetraperoxochromate Cr(V). Cr(V) is then involved in the formation of •OH radicals. In the presence of ligands, the capacity of Cr(V) to form •OH radicals, which are primarily responsible for As(III) oxidation, is practically inhibited. Our findings demonstrate the feasibility for the coconversion of As(III) and Cr(VI) in AMD and real-world constraints to this strategy for environmental remediation. © 2013 American Chemical Society.
- Publisher
- American Chemical Society
- Relation
- Environmental Science and Technology Vol. 47, no. 12 (2013), p. 6486-6492
- Rights
- Copyright © 2013 American Chemical Society.
- Rights
- This metadata is freely available under a CCO license
- Subject
- MD Multidisciplinary; Acid mine drainage; Acidic conditions; As oxidation(III); Attractive strategies; Direct interactions; Environmental remediation; Natural environments; Reaction mechanism
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