Electrochemical depassivation for recovering Fe⁰ reactivity by Cr(VI) removal with a permeable reactive barrier system

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• 作者：Xin Lu^a ; Miao Li^a ; ^{limiaowater@gmail.com} ; Cuimei Tang^b ; Chuanping Feng^c ; Xiang Liu^a
• 关键词：Cr(VI) ; Electro-PRB ; Fe0 ; Passivation ; Electrochemical depassivation
• 刊名：Journal of Hazardous Materials
• 出版年：2012
• 期刊代码：50_03043894
• 类别：ce
• 出版时间：30 April, 2012
• 卷：213-214
• 期：Complete
• 页码：355-360
• 文件大小：684 K

摘要

A new electrochemical permeable reactive barrier (Electro-PRB) system for removal of hexavalent chromium [Cr(VI)] using Fe⁰ meshes was developed. Electro-PRB was found to be effective for electrochemical depassivation of Fe⁰ to remove Cr(VI) during treatment. During initial treatment, Cr(VI) removal rates decreased with time, due to loss of Fe⁰ reactivity by mineral fouling. After Fe⁰ was passivated, electrochemical depassivation was introduced for different electrolysis times to recover Fe⁰ reactivity. It was found that there was approximately 100.4-131.3%initial removal rate recovery, due to the electrochemical break down of precipitates on the Fe⁰ surfaces. During the treatment, the decreasing pH and increasing oxidation-reduction Potential (ORP) of the effluent implied the passivation of Fe⁰ surfaces. Scanning electron microscope analysis of acid-washed, electrochemically depassivated, and passivated Fe⁰ confirmed the efficiency of Elecro-PRB in the recovery Fe⁰ reactivity. The results indicate that the Electro-PRB system proposed here is capable of recovering the reactivity of Fe⁰, which may prolong the operation of Cr(VI) removal processes.