Kinetics of Reduction of Nitrobenzene and Carbon Tetrachloride at an Iron-Oxide Coated Gold Electrode

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• 作者：Brian A. Logue and John C. Westall
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：June 1, 2003
• 年：2003
• 卷：37
• 期：11
• 页码：2356 - 2362
• 全文大小：201K
• 年卷期：v.37,no.11(June 1, 2003)
• ISSN：1520-5851

文摘

The rates of reduction of carbon tetrachloride (CT) andnitrobenzene (NB) by iron-oxide coated gold electrodeswere studied to gain insight into the processes that controlreduction of groundwater contaminants by zerovalentmetal permeable reactive barriers. Fe(III)-oxide films weredeposited on gold electrodes with a small fraction of the Fe(III) electrochemically reduced to Fe(II) to investigate therole of Fe(II) in the reduction of the CT and NB. Mass transportto the surface of the oxide film was controlled throughuse of a well-defined flow-through system similar to a wall-jet electrode. The factors affecting the overall reductionrate were investigated by varying the Fe(II) content in the iron-oxide, controlling mass transport of the electroactivespecies to the oxide surface, and varying the thickness ofthe oxide film. The rates of reduction of CT and NBwere found to be independent of Fe(II) content in the iron-oxide and were only slightly dependent on the rate oftransport to the surface of the oxide under a few sets ofreaction conditions. Conversely, the rates of reduction weregreatly dependent on the thickness of the oxide film,with the reduction rate decreasing as the oxide thicknessincreased. Evidence suggests that the location of thereduction reaction for CT and NB is at the gold surfaceand supports a barrier model for the system studied, in whichthe oxide film physically impedes direct contact of theelectroactive species and the gold electrode, increasesthe diffusion path length, and creates adsorption sites.