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首页> 外文期刊>Environmental Science & Technology >Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes
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Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes

机译：了解使用旋转环盘电极的钒（V）水溶液和转化产物的还原动力学

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摘要

Vanadium(V) is an emerging contaminant in the most recent Environmental Protection Agency's candidate contaminant list (CCL4). The redox chemistry of vanadium controls its occurrence in the aquatic environment, but the impact of vanadium(V) speciation on the redox properties remains largely unknown. This study utilized the rotating ring-disk electrode technique to examine the reduction kinetics of four pH- and concentration-dependent vanadium(V) species in the presence and the absence of phosphate. Results showed that the reduction of VO_2~+, H_xV_4O_(12+x)~((4+x)-) (V_4), and HVO_4~(2-) proceeded via a one-electron transfer, while that of Na_xH_yV_(10)O_(28)~((6-x-y)-) (V_(10)) underwent a two-electron transfer. Koutecky-Levich and Tafel analyses showed that the intrinsic reduction rate constants followed the order of V_(10) > VO_2~+ > V_4 > HVO_4~(2-). Ring-electrode collection efficiency indicated that the reduction product of V_(10) was stable, while those of VO_2~+, HVO_4~(2-), and V_4 had short half-lives that ranged from milliseconds to seconds. With molar ratios of phosphate to vanadium(V) varying from 0 to 1, phosphate accelerated the reduction kinetics of V_(10) and V_4 and enhanced the stability of the reduction products of VO_2~+, V_4, and HVO_4~(2-). This study suggests that phosphate complexation could enhance the reductive removal of vanadium(V) and inhibit the reoxidation of its reduction product in water treatment.
机译：钒是最新出现的环境保护局候选污染物清单（CCL4）中的污染物。钒的氧化还原化学作用控制了其在水生环境中的发生，但钒（V）形态对氧化还原性能的影响仍然未知。这项研究利用旋转圆盘电极技术研究了在存在和不存在磷酸盐的情况下，四种pH和浓度依赖性钒（V）物种的还原动力学。结果表明，VO_2〜+，H_xV_4O_（12 + x）〜（（4 + x）-）（V_4）和HVO_4〜（2-）的还原通过单电子转移进行，而Na_xH_yV_（10 O_（28）〜（（6-xy）-）（V_（10））经历了两次电子转移。 Koutecky-Levich和Tafel分析表明，固有还原速率常数遵循V_（10）> VO_2〜+> V_4> HVO_4〜（2-）的顺序。环电极收集效率表明，V_（10）的还原产物是稳定的，而VO_2〜+，HVO_4〜（2-）和V_4的还原产物的半衰期较短，范围从毫秒到秒。磷酸盐与钒（V）的摩尔比在0到1之间变化时，磷酸盐加速了V_（10）和V_4的还原动力学，并增强了VO_2〜+，V_4和HVO_4〜（2-）的还原产物的稳定性。 。这项研究表明，磷酸盐络合可以增强水处理中钒（V）的还原去除并抑制其还原产物的再氧化。

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  • 来源
    《Environmental Science & Technology》 |2017年第20期|11643-11651|共9页
  • 作者

    Chen Gongde; Liu Haizhou;

  • 作者单位

    Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, CA, United States;

    Department of Chemical and Environmental Engineering, University of California at Riverside, Riverside, CA, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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