Quantum chemistry study on the destruction mechanism of 2,3,7,8-TCDD by OH and O(3) radicals.
Quantum chemistry study on the destruction mechanism of 2,3,7,8-TCDD by OH and O(3) radicals.
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DOI：
10.1016/j.chemosphere.2013.03.027
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发表时间：
2013-07
期刊：
影响因子：
8.8
通讯作者：
Z. Wen;Zhihua Wang;Jiang-rong Xu;Yang Liu;K. Cen
中科院分区：
文献类型：
--
作者：
Z. Wen;Zhihua Wang;Jiang-rong Xu;Yang Liu;K. Cen
由于二恶英具有重要的基础作用，本文采用量子化学计算的方法详细研究了以2,3,7,8- tcdd为例的二恶英被OH和o3自由基破坏的机理。理论结果表明，OH自由基通过在2,3,7,8位取代氯来降解2,3,7,8- tcdd，而o3自由基通过破坏CC键和芳环来降解2,3,7,8- tcdd。在机理研究的基础上，利用过渡态理论计算了反应的动力学参数。通过比较发现，OH对2,3,7,8- tcdd的降解速率常数远大于O3，表明OH自由基对2,3,7,8- tcdd的降解能力远大于O3自由基。这一发现与OH和o3自由基的标准电极电位一致。本文的理论结果可为进一步研究催化氧化技术对二恶英的去除提供重要的理论依据。
Due to its fundamental importance, the destruction mechanism of the dioxins, as exemplified by 2,3,7,8-TCDD, by OH and O3radicals was investigated in detail employing Quantum Chemical Calculations in this paper. Theoretical results showed that, OH radical degraded 2,3,7,8-TCDD via substituting chlorine at the 2,3,7,8 positions, while O3radical degraded 2,3,7,8-TCDD via destructing CC bonds and aromatic ring. Based on the mechanism study, the kinetic parameters of the reactions were also calculated by Transition State Theory. By comparing, the rate constant of the 2,3,7,8-TCDD destruction by OH was found to be much higher than that by O3, which indicated that OH radical have much stronger ability to degrade 2,3,7,8-TCDD than O3radical. This finding was consistent with the standard electrode potential of OH and O3radical. The theoretical results in this paper can be believed to supply important theory basis for the further investigation on dioxins removal by using the catalytic oxidation technology.