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首页> 外文期刊>Environmental Science & Technology >Mechanisms for Abiotic Dechlorination of Trichloroethene by Ferrous Minerals under Oxic and Anoxic Conditions in Natural Sediments
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Mechanisms for Abiotic Dechlorination of Trichloroethene by Ferrous Minerals under Oxic and Anoxic Conditions in Natural Sediments

机译：天然沉积物在含氧和缺氧条件下亚铁矿物对三氯乙烯进行非生物脱氯的机理

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摘要

Bench-scale experiments were performed on natural sediments to assess abiotic dechlorination of trichloroethene (TCE) under both aerobic and anaerobic conditions. In the absence of oxygen (26 mu M), TCE dechlorination proceeded via a reductive pathway generating acetylene and/or ethene. Reductive dechlorination rate constants up to 3.1 x 10(-5) d(-1) were measured, after scaling to in situ solid:water ratios. In the presence of oxygen greater than 120 mu M, TCE dechlorination proceeded via an oxidative pathway generating formic/glyoxylic and glycolic/acetic acids, and oxidative dechlorination rate constants (again scaled to in situ conditions) up to 7.4 x 10(-3) d(-1) were measured. These rates correspond to half-lives of 60 and 0.25 years for abiotic TCE dechlorination under anaerobic and aerobic conditions, respectively, indicating the potentially large impact of aerobic TCE oxidation in the field. For both reductive and oxidative TCE dechlorination pathways, measured first-order rate constants increased with increasing ferrous iron content, suggesting the role of iron oxidation. Hydroxyl radical formation was measured and increased with increasing oxygen and ferrous iron content. Rate constants associated with TCE oxidation products increased with increasing hydroxyl radical generation rates, and were zero in the presence of a hydroxyl radical scavenger, suggesting that oxidative TCE dechlorination is a hydroxyl radical driven process.
机译：在有氧和无氧条件下，对天然沉积物进行了规模试验，以评估三氯乙烯（TCE）的非生物脱氯。在没有氧气（<26μM）的情况下，TCE脱氯反应通过还原途径生成乙炔和/或乙烯。在按比例缩放到原位固水比后，测量到的还原脱氯速率常数高达3.1 x 10（-5）d（-1）。在氧气大于120μM的情况下，TCE的脱氯反应通过氧化途径生成甲酸/乙醛酸和乙醇酸/乙酸，氧化脱氯速率常数（再次按比例缩放至原位条件）高达7.4 x 10（-3）测量d（-1）。这些速率分别对应于在厌氧和好氧条件下非生物TCE脱氯的半衰期分别为60年和0.25年，表明该领域中有氧TCE氧化的潜在巨大影响。对于还原性和氧化性TCE脱氯途径，测得的一级速率常数随着亚铁含量的增加而增加，表明铁的氧化作用。测量了羟基自由基的形成，并随着氧和亚铁含量的增加而增加。与TCE氧化产物相关的速率常数随羟基自由基生成速率的增加而增加，在存在羟基自由基清除剂的情况下为零，这表明氧化TCE脱氯是羟基自由基驱动的过程。

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  • 来源
    《Environmental Science & Technology》 |2018年第23期|13747-13755|共9页
  • 作者

    Schaefer Charles E.; Ho Paul; Berns Erin; Werth Charles;

  • 作者单位

    CDM Smith, 14432 SE Eastgate Way 100, Bellevue, WA 98007 USA;

    Univ Texas Austin, Civil Architectural & Environm Engn, 301 E Dean Keeton St,Stop C1786, Austin, TX 78712 USA;

    CDM Smith, 110 Fieldcrest Ave,8,6th Floor, Edison, NJ 08837 USA;

  • 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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