Electrochemically Induced Oxidative Precipitation of Fe(II) for As(III) Oxidation and Removal in Synthetic Groundwater

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• 作者：Man Tong ; Songhu Yuan ; Peng Zhang ; Peng Liao ; Akram N. Alshawabkeh ; Xianjun Xie ; Yanxin Wang
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 6, 2014
• 年：2014
• 卷：48
• 期：9
• 页码：5145-5153
• 全文大小：517K
• 年卷期：v.48,no.9(May 6, 2014)
• ISSN：1520-5851

文摘

Mobilization of Arsenic in groundwater is primarily induced by reductive dissolution of As-rich Fe(III) oxyhydroxides under anoxic conditions. Creating a well-controlled artificial environment that favors oxidative precipitation of Fe(II) and subsequent oxidation and uptake of aqueous As can serve as a remediation strategy. We reported a proof of concept study of a novel iron-based dual anode system for As(III) oxidation and removal in synthetic groundwater. An iron anode was used to produce Fe(II) under iron-deficient conditions, and another inert anode was used to generate O₂ for oxidative precipitation of Fe(II). For 30 min鈥檚 treatment, 6.67 渭M (500 渭g/L) of As(III) was completely oxidized and removed from the solution during the oxidative precipitation process when a total current of 60 mA was equally partitioned between the two anodes. The current on the inert anode determined the rate of O₂ generation and was linearly related to the rates of Fe(II) oxidation and of As oxidation and removal, suggesting that the process could be manipulated electrochemically. The composition of Fe precipitates transformed from carbonate green rust to amorphous iron oxyhydroxide as the inert anode current increased. A conceptual model was proposed for the in situ application of the electrochemically induced oxidative precipitation process for As(III) remediation.