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首页> 外文期刊>Environmental Science & Technology >Oxidation on Zerovalent Iron Promoted by Polyoxometalate as an Electron Shuttle
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Oxidation on Zerovalent Iron Promoted by Polyoxometalate as an Electron Shuttle

机译：多金属氧酸盐促进的零价铁作为电子穿梭物的氧化

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摘要

Most studies on zerovalent iron (ZVI) were mainly focused on the reductive transformation of halo- or nitro-compounds. Oxidation reactions occurring on ZVI have been recently recognized. In this study, we demonstrate that the oxidation pathways on ZVI can be accelerated by the presence of polyoxometalate (POM: nanosized metal- oxygen cluster anion) serving as an electron shuttle. The ions, SiW_(12)O_(40)~(4-) and PW_(12)O_(40)~(3-), can mediate the electron transfer from the Fe~0 surface to O_2 while enhancing the production of H_2O_2, which subsequently initiates the OH radical-mediated oxidation through a Fenton-type reaction. The oxidation reaction was completely quenched by adding methanol as an OH radical-scavenger. On the other hand, PMo_(12)O_(40)~(3-) completely inhibited the oxidative degradation by irreversibly scavenging an electron and holding it. We systematically investigated the effects of iron loading, the concentration of POM, and pH on the oxidative degradation kinetics of 4-chlorophenol in the POM-mediated ZVI system. The POM-mediated oxidations on ZVI were additionally tested for 12 organic contaminants and the rates were compared. Their oxidative degradation on ZVI was mostly enhanced in the presence of POM (SiW_(12)O_(40)~(4-)). The present study provides a good model system upon which the ZVI-based oxidation technologies can be successfully enhanced and modified for further developments.
机译：零价铁（ZVI）的大多数研究主要集中于卤代化合物或硝基化合物的还原转化。最近已经认识到在ZVI上发生的氧化反应。在这项研究中，我们证明ZVI上的氧化途径可以通过作为电子穿梭物的多金属氧酸盐（POM：纳米级金属-氧簇阴离子）的存在而加速。 SiW_（12）O_（40）〜（4-）和PW_（12）O_（40）〜（3-）离子可介导电子从Fe〜0表面到O_2的转移，同时提高H_2O_2的产生，随后通过Fenton型反应引发OH自由基介导的氧化。通过添加甲醇作为OH自由基清除剂将氧化反应完全淬灭。另一方面，PMo_（12）O_（40）〜（3-）通过不可逆地清除电子并保持电子来完全抑制氧化降解。我们系统地研究了铁负载，POM的浓度和pH对POM介导的ZVI系统中4-氯苯酚氧化降解动力学的影响。还对ZVI上POM介导的氧化进行了12种有机污染物的测试，并比较了速率。在POM（SiW_（12）O_（40）〜（4-））的存在下，它们在ZVI上的氧化降解大部分得以增强。本研究提供了一个良好的模型系统，基于ZVI的氧化技术可以成功地进行增强和修改以进一步发展。

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  • 来源
    《Environmental Science & Technology》 |2007年第9期|p.3335-3340|共6页
  • 作者

    JAESANG LEE; JUNGWON KIM; WONYONG CHOI;

  • 作者单位

    School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea;

  • 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);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
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