羟基自由基对毒性PCDD破坏机理及动力学的理论研究

IF 0.5 4区环境科学与生态学 Q4 ENVIRONMENTAL SCIENCES

International Journal of Environment and Pollution Pub Date : 2019-11-21 DOI:10.1504/ijep.2019.103749

Z. Wen, Shengji Li, Heping Li, Yuan Li

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引用次数: 0

摘要

利用量子化学方法详细研究了羟基自由基对毒性PCDDs的破坏机理和动力学。结果表明，OH自由基通过在2、3、7、8位取代氯来降解有毒的PCDDs。采用过渡态理论计算了动力学参数。OH对OCDD的破坏速率常数与实验结果一致，特别是在298K时。2，3，7，8-TCDD的破坏速度常数明显低于其他毒性PCDD。利用NBO电荷分析法对原因进行了探讨。由于Cl原子在1、4、6、9位的活化作用，在2、3、7、8位的C原子具有更多的负电荷。在芳环上，如果碳带更多的负电荷，碳更容易被OH攻击，相邻的Cl更容易被取代。

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A theoretical study on the mechanism and kinetics of toxic PCDD destruction by OH radicals

The mechanism and kinetics of toxic PCDDs destruction by OH radicals is investigated in detail by employing quantum chemistry. Results show that the OH radical degrades toxic PCDDs via substituting chlorine at the 2, 3, 7, 8 positions. The kinetic parameters are calculated by adopting transition state theory. The rate constant of OCDD destruction by OH is in agreement with the experimental result, especially at 298 K. The rate constants of 2, 3, 7, 8-TCDD destruction are obviously lower than those of other toxic PCDDs. The reason is discussed by using the NBO charge analysis. Owing to the activation effect of Cl atoms at 1, 4, 6, 9 positions, C atoms at 2, 3, 7, 8 positions have more negative charge. At aromatic rings, if the carbon has more negative charge, the carbon is more easily attacked by OH and the adjacent Cl is more easily substituted.

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来源期刊

International Journal of Environment and Pollution 环境科学-环境科学

CiteScore

1.10

自引率

0.00%

发文量

审稿时长

4.5 months

期刊介绍： IJEP provides an international forum in the field of environment and pollution and addresses early and medium-term challenges involving scientific prediction, modelling and assessment. It focuses on ground-breaking research in the science of environmental pollution, at the early scientific stage. It is one of three key journals which together offer complete coverage of environmental issues: IJETM focuses on technical/engineering, policy and management solutions for environmental problems, and IJGEnvI focuses on future, longer-term environmental scenarios, ecological economics, climate change and biodiversity.