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首页> 外文期刊>Environmental Science & Technology >Iodine-Sensitized Degradation of 2,4,6-Trichlorophenol under Visible Light
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Iodine-Sensitized Degradation of 2,4,6-Trichlorophenol under Visible Light

机译：可见光下碘敏降解2,4,6-三氯苯酚

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摘要

Molecular iodine has been studied, for the first time, as a sensitizer for the degradation of 2,4,6-trichIor- ophenol (TCP) in aqueous solution under visible light (λ ≥ 450 nm). TCP was degraded in the presence of commercial I_v but the reaction rate decreased significantly after 2 h. When a solution of Nal and H_2O_2 was used as an iodine source with phosphotungstic acid (PW) as a catalyst, TCP degradation was not only fast but also followed zero-order kinetics. Importantly, the I_2 concentration remained unchanged with time, indicative of I_2 recycling as a kind of photocatalyst. During TCP degradation, 2,6-dichloro-l,4-benzoquinone was produced as the main intermediate (76%), which slowly degraded in the irradiated solution. For every equivalent of TCP consumed at the 2 h time point, approximately 1.7 equivalents of chloride ions were produced. Further study of the effect of variables including the type of polyoxometalates (POM) and the initial concentration of each component revealed that the rate of TCP degradation under visible light was determined by the rate of I_2 production in the dark. The optimum pH and apparent activation energy for TCP disappearance were 4.5 and 42.8 kJ/mol, respectively. It is proposed that TCP degradation is initiated by iodine radicals produced from I_2 photolysis, followed by I_2 regeneration through a POM-catalyzed oxidation of I_3~- by H_2O_2.
机译：分子碘首次被用作敏化剂，用于在可见光（λ≥450 nm）下降解水溶液中的2,4,6-trichI-邻苯二酚（TCP）。在商业I_v存在下，TCP降解，但2小时后反应速率显着下降。当使用Nal和H_2O_2的溶液作为碘源并以磷钨酸（PW）作为催化剂时，TCP降解不仅很快，而且遵循零级动力学。重要的是，I_2的浓度随时间保持不变，表明I_2作为一种光催化剂可以循环利用。在TCP降解过程中，产生了2,6-二氯-1,4-苯醌作为主要中间体（76％），在照射的溶液中缓慢降解。对于2小时时间点消耗的TCP的每当量，大约产生1.7当量的氯离子。进一步研究变量的影响，包括多金属氧酸盐（POM）的类型和每种成分的初始浓度，发现可见光下TCP的降解速率取决于黑暗中I_2的产生速率。 TCP消失的最佳pH和表观活化能分别为4.5和42.8 kJ / mol。提出TCP降解是由I_2光解产生的碘自由基引发的，然后通过POM催化的H_2O_2氧化I_3〜-而使I_2再生。

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  • 来源
    《Environmental Science & Technology》 |2012年第16期|p.9005-9011|共7页
  • 作者

    Meiqin Hu; Yan Wang; Zhigang Xiong; Dongqin Bi; Yuhong Zhang; Yiming Xu;

  • 作者单位

    Department of Chemistry, Zhejiang University, Hangzhou 310027, China,Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, P. R. China;

    Department of Chemistry, Zhejiang University, Hangzhou 310027, China;

    Department of Chemistry, Zhejiang University, Hangzhou 310027, China;

    Department of Chemistry, Zhejiang University, Hangzhou 310027, China;

    Department of Chemistry, Zhejiang University, Hangzhou 310027, China;

    Department of Chemistry, Zhejiang University, Hangzhou 310027, 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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