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首页> 外文期刊>Environmental Science & Technology >Redox Control and Hydrogen Production in Sediment Caps Using Carbon Cloth Electrodes
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Redox Control and Hydrogen Production in Sediment Caps Using Carbon Cloth Electrodes

机译：碳布电极在沉积物帽中的氧化还原控制和产氢

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摘要

Sediment caps that degrade contaminants can improve their ability to contain contaminants relative to sand and sorbent-amended caps, but few methods to enhance contaminant degradation in sediment caps are available. The objective of this study was to determine if, carbon electrodes emplaced within a sediment cap at poised potential could create a redox gradient and provide electron donor for the potential degradation of contaminants. In a simulated sediment cap overlying sediment from the Anacostia River (Washington, DC), electrochemically induced redox gradients were developed within 3 days and maintained over the period of the test (-100 days). Hydrogen and oxygen were produced by water electrolysis at the electrode surfaces and may serve as electron donor and acceptor for contaminant degradation. Electrochemical and geochemical factors that may influence hydrogen production were studied. Hydrogen production displayed zero order kinetics with ～75% Coulombic efficiency. Rates were proportional to the applied potential between 2.5 and 5 V and not greatly affected by pH. Hydrogen production was promoted by increasing ionic strength and in the presence of natural organic matter. Carbon electrode-stimulated degradation of tetrachlorobenzene in a batch reactor was dependent on applied voltage and production of hydrogen to a concentration above the threshold for biological dechlorination. These findings suggest that electrochemical reactive capping can potentially be used to create "reactive" sediments caps capable of promoting chemical or biological transformations of contaminants within the cap.
机译：相对于沙子和吸附剂改良的盖，降解污染物的沉积物盖可以提高其容纳污染物的能力，但是很少有方法可以增强沉积物盖中的污染物降解。这项研究的目的是确定放置在沉积物帽中处于平衡电位的碳电极是否会产生氧化还原梯度并为污染物的潜在降解提供电子给体。在来自Anacostia河（华盛顿特区）的模拟沉积物上覆盖层中，电化学诱导的氧化还原梯度在3天内形成，并在测试期间（-100天）保持不变。氢和氧是由水在电极表面电解产生的，可以用作污染物降解的电子给体和受体。研究了可能影响氢气产生的电化学和地球化学因素。制氢过程显示出零级动力学，库仑效率约为75％。速率与2.5至5 V之间的施加电势成比例，不受pH的影响很大。通过增加离子强度和在天然有机物的存在下促进了产氢。在间歇反应器中，碳电极刺激的四氯苯降解取决于所施加的电压和氢的产生，其浓度超过生物脱氯的阈值。这些发现表明，电化学反应性封盖可以潜在地用于产生“反应性”沉积物盖，其能够促进盖内污染物的化学或生物转化。

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  • 来源
    《Environmental Science & Technology》 |2010年第21期|p.8209-8215|共7页
  • 作者

    MEI SUN; FEI YAN; RUILING ZHANG; DANNY D. REIBLE; GREGORY V. LOWRY; KELVIN B. GREGORY;

  • 作者单位

    Department of Civil and Environmental Engineering,University of Texas, Austin, Texas 78712, United Stales;

    rnEnvironmental and Water Resources Engineering, University of Texas, Austin, Texas 78712, United Stales;

    rnEnvironmental and Water Resources Engineering, University of Texas, Austin, Texas 78712, United Stales;

    rnEnvironmental and Water Resources Engineering, University of Texas, Austin, Texas 78712, United Stales;

    rnDepartment of Civil and Environmental Engineering,University of Texas, Austin, Texas 78712, United Stales Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-3890, United States;

    rnDepartment of Civil and Environmental Engineering,University of Texas, Austin, Texas 78712, United Stales;

  • 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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