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首页> 外文期刊>Environmental Science & Technology >A New Mechanism in Electrochemical Process for Arsenic Oxidation: Production of H_2O_2 from Anodic O_2 Reduction on the Cathode under Automatically Developed Alkaline Conditions
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A New Mechanism in Electrochemical Process for Arsenic Oxidation: Production of H_2O_2 from Anodic O_2 Reduction on the Cathode under Automatically Developed Alkaline Conditions

机译：砷氧化电化学过程中的新机理：在自动开发的碱性条件下，阴极上的阳极O_2还原产生H_2O_2

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摘要

Electrochemical cathodes are often used to reduce contaminants or produce oxidizing substances (i.e., H_2O_2). Alkaline conditions develop automatically around the cathode in electrochemical processes, and O_2 diffuses onto the cathode easily. However, limited attention is paid to contaminant transformation by the reactive species produced on the cathode under oxic and alkaline conditions due to the inapplicability of pH for Fenton reaction. In this study, a new oxidation mechanism on the cathode is presented for contaminant transformation under automatically developed alkaline conditions. In an electrochemical sand column, 6.67 μM As(Ⅲ) was oxidized by 36% when it passed through the cathode under the conditions of 30 mA current, an initial pH of 7.5 and a flow rate of 2mL/min. Under the alkaline conditions (pH 10.0-11.0) that developed automatically around the cathode, the reduction potential of As(Ⅲ) decreased greatly, allowing a pronounced oxidation by the small quantities of H_2O_2 produced from O_2 reduction on the cathode. As(Ⅲ) oxidation was further increased by the presence of soil pore water and groundwater solutes of HCO_3~-, Ca~(2+), Mg~(2+) and humic acid. The new oxidation mechanism found for the cathode under localized alkaline conditions supplements the fundamentals of contaminant transformation in electrochemical processes.
机译：电化学阴极通常用于减少污染物或产生氧化性物质（即H_2O_2）。碱性条件在电化学过程中会自动在阴极周围发展，并且O_2容易扩散到阴极上。然而，由于pH值不适用于芬顿反应，因此在氧气和碱性条件下，在阴极上产生的反应性物质对污染物转化的关注有限。在这项研究中，提出了一种在阴极上的新氧化机制，用于在自动开发的碱性条件下进行污染物转化。在电化学砂塔中，当在30 mA电流，初始pH值为7.5和流速为2mL / min的条件下通过阴极时，6.67μMAs（Ⅲ）被氧化36％。在阴极周围自动产生的碱性条件（pH 10.0-11.0）下，As（Ⅲ）的还原电位大大降低，使得阴极上O_2还原产生的少量H_2O_2引起明显的氧化。随着土壤孔隙水和HCO_3〜-，Ca〜（2 +），Mg〜（2+）和腐殖酸的地下水溶质的存在，As（Ⅲ）的氧化进一步增加。在局部碱性条件下发现的用于阴极的新氧化机理补充了电化学过程中污染物转化的基础。

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  • 来源
    《Environmental Science & Technology》 |2015年第9期|5689-5696|共8页
  • 作者

    Ao Qian; Songhu Yuan; Peng Zhang; Man Tong;

  • 作者单位

    State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China,School of Environmental Studies, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China;

    State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China,School of Environmental Studies, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China;

    State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China;

    State Key Lab of Biogeology and Environmental Geology, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China,School of Environmental Studies, China University of Geosciences, 388 Lumo Road, Wuhan, 430074, P. R. China;

  • 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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