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Rapid debromination of polybrominated diphenyl ethers (PBDEs) by zero valent metal and bimetals: Mechanisms and pathways assisted by density function theory calculation

机译:零价金属和双金属对多溴联苯醚(PBDEs)的快速脱溴:密度泛函理论计算辅助的机理和途径

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摘要

Polybrominated diphenyl ethers (PBDEs) undergo debromination when they were exposed in zerovalent metal or bimetallic systems. Yet their debromination pathways and mechanisms in these systems were not well understood. Here we reported the debromination pathways of three BDE congeners (BDE-21, 25 and 29) by nano-zerovalent iron (n-ZVI). All these BDE congeners have three bromine substituents that were located in ortho-, meta-and para-positions. Results demonstrated that BDE-21, 25 and 29 preferentially debrominate meta-, ortho- and para-bromines, respectively, suggesting that bromine substituent at each position (i.e. ortho-, meta-or para-) of PBDEs can be preferentially removed. Singly occupied molecular orbitals of BDE anions are well correlated with their actual debromination pathways, which successfully explain why these BDE congeners exhibit certain debromination pathways in n-ZVI system. In addition, microscale zerovalent zinc (m-ZVZ), iron-based bimetals (Fe/Ag and Fe/Pd) were also used to debrominate PBDEs, with BDE-21 as target pollutant. We found that the debromination pathways of BDE-21 in m-ZVZ and Fe/Ag systems are the same to those in n-ZVI system, but were partially different from those in Fe/Pd systems. The debromination of BDE-21 in Pd-H-2 system as well as the solvent kinetic isotope effect in single metal and bimetallic systems suggests that H atom transfer is the dominant mechanism in Fe/Pd system, while e-transfer is still the dominant mechanism in Fe/Ag system. (C) 2018 Elsevier Ltd. All rights reserved.
机译:当多溴联苯醚(PBDEs)暴露于零价金属或双金属体系中时,会发生脱溴作用。然而,它们在这些系统中的脱溴途径和机理尚未得到很好的了解。在这里,我们报道了纳米零价铁(n-ZVI)对三种BDE同系物(BDE-21、25和29)的脱溴途径。所有这些BDE同系物都有三个位于邻位,间位和对位的溴取代基。结果表明,BDE-21、25和29分别优先清除间溴,邻溴和对溴,这表明可以优先除去PBDEs每个位置(即邻,间或对位)上的溴取代基。 BDE阴离子的单占据分子轨道与它们的实际脱溴途径密切相关,这成功地解释了为什么这些BDE同源物在n-ZVI系统中表现出某些脱溴途径。此外,还使用微量零价锌(m-ZVZ),铁基双金属(Fe / Ag和Fe / Pd)来脱溴多溴二苯醚,其中BDE-21作为目标污染物。我们发现,m-ZVZ和Fe / Ag系统中BDE-21的脱溴途径与n-ZVI系统中的相同,但与Fe / Pd系统中的溴脱除途径部分不同。 Pd-H-2系统中BDE-21的脱溴作用以及单金属和双金属系统中的溶剂动力学同位素效应表明,H原子转移是Fe / Pd系统中的主要机理,而电子转移仍是主要的机理Fe / Ag系统的机理(C)2018 Elsevier Ltd.保留所有权利。

著录项

  • 来源
    《Environmental Pollution》 |2018年第9期|745-753|共9页
  • 作者单位

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples R China;

    Chinese Res Inst Environm Sci, State Key Lab Environm Criteria & Risk Assessment, Beijing 100012, Peoples R China;

    South China Univ Technol, Sch Environm & Energy, Guangzhou 510006, Guangdong, Peoples 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);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Polybrominated diphenyl ethers; Debromination pathways; Nanoscale zerovalent iron; Bimetal; Molecular orbitals;

    机译:多溴联苯醚;脱溴途径;纳米级零价铁;双金属;分子轨道;
  • 入库时间 2022-08-17 13:25:54

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