School of Resources and Environment, University of Jinan, 250022, Jinan, PR China.
Association of Chinese Chemists and Chemical Engineers in Germany, 67117, Limburgerh of, Germany; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023, Nanjing, PR China.
Water Res. 2018 May 15;135:144-154. doi: 10.1016/j.watres.2018.02.028. Epub 2018 Feb 13.
Sulfate radical (SO)-induced oxidation is an important technology in advanced oxidation processes (AOPs) for the removal of pollutants. To date, few studies have assessed the effects of dissolved oxygen (DO) on the SO-induced oxidation of organic micro-pollutants. In the present work, a quantum chemical calculation was used to investigate the influence of the external oxygen molecule on the Gibbs free energy (G) and HOMO-LUMO gap (ΔE) of 15 organic micro-pollutants representing four chemical categories. Several thermodynamic and statistical models were combined with the data from the quantum chemical calculation to illustrate the impact of DO on the oxidation of organic micro-pollutants by SO. Results indicated that the external oxygen molecule increased G of all studied chemicals, which implies DO has the potential to decrease the energy barrier of the SO-induced oxidation and shift the chemical equilibrium of the reaction towards the side of products. From the perspective of kinetics, DO can accelerate the oxidation by decreasing ΔE of organic micro-pollutants. In addition, changes of G and ΔE of the SO-induced oxidation were both significantly different between open-chain and aromatic chemicals, and these differences were partially attributed to the difference of polarizability of these two types of chemicals. Furthermore, we revealed that all changes of G and ΔE induced by DO were dependent on the DO content. Our study emphasizes the significance of DO on the oxidation of organic micro-pollutants by SO, and also provides a theoretical method to study the effect of components in wastewater on removal of organic pollutants in AOPs.
硫酸盐自由基（SO）诱导氧化是高级氧化工艺（AOPs）中去除污染物的一项重要技术。迄今为止，很少有研究评估溶解氧（DO）对有机微量污染物的 SO 诱导氧化的影响。在本工作中，使用量子化学计算研究了外部氧分子对代表四个化学类别的 15 种有机微量污染物的吉布斯自由能（G）和 HOMO-LUMO 能隙（ΔE）的影响。将几种热力学和统计模型与量子化学计算的数据相结合，说明了 DO 对 SO 氧化有机微量污染物的影响。结果表明，外部氧分子增加了所有研究化学品的 G，这意味着 DO 有可能降低 SO 诱导氧化的能量障碍，并使反应的化学平衡向产物侧移动。从动力学的角度来看，DO 可以通过降低有机微量污染物的 ΔE 来加速氧化。此外，SO 诱导氧化的 G 和 ΔE 的变化在开链和芳香族化学品之间也有显著差异，这些差异部分归因于这两种类型化学品的极化率差异。此外，我们揭示了 DO 引起的 G 和 ΔE 的所有变化都取决于 DO 含量。本研究强调了 DO 对 SO 氧化有机微量污染物的重要性，同时也提供了一种理论方法来研究废水中成分对 AOPs 中有机污染物去除的影响。
