Quantitative structure-activity relationship models for predicting reaction rate constants of organic contaminants with hydrated electrons and their mechanistic pathways
Quantitative structure-activity relationship models for predicting reaction rate constants of organic contaminants with hydrated electrons and their mechanistic pathways
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用于预测有机污染物与水合电子的反应速率常数及其机理路径的定量构效关系模型
DOI：
10.1016/j.watres.2018.12.010
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发表时间：
2019
期刊：
影响因子：
12.8
通讯作者：
Zhao Yuanhui.
中科院分区：
文献类型：
--
作者：
Li Chao;Zheng Shanshan;Li Tiantian;Chen Jingwen;Zhou Junhui;Su Limin;Zhang Ya-nan;Crittenden J.C.;Zhu Suiyi;Zhao Yuanhui.
基于水合电子（e aq−）的还原过程有望去除水工程系统中的有机污染物。还原动力学，尤其是有机化合物 e aq− 的二阶速率常数 (ke aq−)，对于评估和建模高级还原过程非常重要。在这项研究中，首次通过定量构效关系（QSAR）方法对脂肪族化合物和苯基化合物的 k e aq− 值进行建模。揭示了控制两类有机化合物对 e aq− 的反应性的结构特征，并且发现最低未占据分子轨道的能量 (E LUMO)、单电子还原电位 (E RED) 和极化率 (α) 是两个模型中的重要分子参数。构建的 QSAR 模型提供了强大的预测工具，用于估计废水处理过程中使用 e aq− 去除新兴污染物的情况。此外，还采用量子化学计算来探讨基于 e aq− 的还原过程中单电子转移（SET）途径的机制和可行性。热力学研究表明，与具有供电子基团的化合物相比，具有吸电子基团的化合物往往具有更高的 k e aq− 和更低的吉布斯自由能 (Δ G SET) 和吉布斯活化自由能 (Δ‡ G SET∘)，这表明 SET 过程更容易发生。还发现难熔卤代化合物可以通过SET途径实现脱卤。
The hydrated electron (e aq−)-based reduction processes are promising for removing organic pollutants in water engineering systems. The reductive kinetics, especially the second order rate constants (k e aq−) of e aq− with organic compounds, is important for evaluating and modeling the advanced reduction processes. In this study, the k e aq− values for aliphatic compounds and phenyl-based compounds are, for the first time, modeled by the quantitative structure-activity relationship (QSAR) method. The structural features governing the reactivity of two classes of organic compounds toward e aq− were revealed, and the energy of the lowest unoccupied molecular orbital (E LUMO), one-electron reduction potential (E RED) and polarizability (α) were found to be the important molecular parameters in both two models. The built QSAR models provide robust predictive tools for estimating the removal of emerging pollutants using e aq− during wastewater treatment processes. Additionally, quantum chemical calculations were employed to probe into the mechanism and feasibility of the single electron transfer (SET) pathway in the e aq−-based reduction process. The thermodynamic investigation suggests that the compounds with electron-withdrawing groups tend to possess higher k e aq− and lower Gibbs free energy (Δ G SET) and Gibbs free energies of activation (∆‡ G SET∘) than the ones with electron-donating groups, indicating the SET process occurs more readily. It is also found that the refractory halogenated compounds can achieve dehalogenation via the SET pathway.