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首页> 外文期刊>Environmental Science & Technology >Hydroxyl Radical Formation upon Oxidation of Reduced Humic Acids by Oxygen in the Dark
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Hydroxyl Radical Formation upon Oxidation of Reduced Humic Acids by Oxygen in the Dark

机译：氧气在黑暗中氧化还原腐殖酸后形成的羟基自由基

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摘要

Humic acids (HAs) accept and donate electrons in many biogeochemical redox reactions at oxic/anoxic interfaces. The products of oxidation of reduced HAs by O_2 are unknown but are expected to yield reactive oxygen species, potentially including hydroxyl radical (-OH). To quantify the formation of OH upon oxidation of reduced HAs by O_2, three HAs were reduced electrochemically to well-defined redox states and were subsequently oxidized by O_2 in the presence of the OH probe terephthalate. The formation of OH upon oxidation increased with increasing extent of HA reduction. The yield of -OH ranged from 42 to 160 mmol per mole of electrons donated by the reduced HA. The intermediacy of hydrogen peroxide (H_2O_2) in the formation of OH was supported by enhancement of OH formation upon addition of exogenous H_2O_2 sources and by the suppression of •OH formation upon addition of catalase as a quencher of endogenous H_2O_2. The formation of OH in the dark during oxidation of reduced HA represents a previously unknown source of OH formation at oxic/anoxic interfaces and may affect the biogeochemical and pollutant redox dynamics at these interfaces.
机译：腐殖酸（HAs）在氧/氧界面上的许多生物地球化学氧化还原反应中接受和提供电子。 O_2还原的HAs的氧化产物是未知的，但预计会产生活性氧，可能包括羟基（-OH）。为了量化还原的HA被O_2氧化后形成的OH，将三个HA电化学还原为明确的氧化还原状态，然后在OH对苯二甲酸酯探针存在下被O_2氧化。氧化时OH的形成随HA还原程度的增加而增加。对于每摩尔由还原的HA提供的电子，-OH的产率为42-160mmol。通过添加外源H_2O_2源增强OH的形成以及通过添加过氧化氢酶作为内源性H_2O_2的猝灭剂而抑制•OH的形成，支持了OH形成中的过氧化氢（H_2O_2）的中间性。在还原的HA氧化过程中，黑暗中OH的形成代表了以前未知的在有氧/缺氧界面上形成OH的来源，并可能影响这些界面处的生物地球化学和污染物氧化还原动力学。

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  • 来源
    《Environmental Science & Technology》 |2012年第3期|p.1590-1597|共8页
  • 作者

    Sarah E. Page; Michael Sander; William A. Arnold; Kristopher McNeill;

  • 作者单位

    Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, United States;

    Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland;

    Department of Civil Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, MN 55455, United States;

    Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland;

  • 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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