Sino-German Centre for Water and Health Research, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China; National Engineering Research Center for Flue Gas Desulfurization, Sichuan University, Chengdu, 610065, China.
Sino-German Centre for Water and Health Research, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China; National Engineering Research Center for Flue Gas Desulfurization, Sichuan University, Chengdu, 610065, China.
Water Res. 2018 Sep 1;140:12-23. doi: 10.1016/j.watres.2018.04.030. Epub 2018 Apr 14.
A highly efficient electrolysis catalyzed ozone (ECO) process was developed for N,N-dimethylacetamide (DMAC) degradation. The pseudo-first-order rate constants (k) of DMAC degradation by ECO process were 1.73-19.09 times greater than those by ozonation and electrolysis processes in a wide pH range of 3.0-10.0. Interestingly, we found O could be generated from ozone decomposition by a radical chain mechanism instead of monovalent reduction of O in ECO system at the initial pH of 3.0. Subsequently, the HO derived from O could participate in Fenton-like and peroxone reactions with the released Fe from iron anode and the aerated O, respectively. Therefore, the extraordinary DMAC removal efficiency was mainly caused by the more generation of OH through the multiple reactions of homogeneous catalytic ozonation, Fenton-like and peroxone in ECO system. Importantly, the roles of involved reactions in ECO system at various initial pH were quantitatively evaluated according to a series of trapping experiments. The results reveal that the solution pH could significantly affect the contributions of various reactions and convert the reaction mechanisms of multiple reactions in ECO system. Finally, the degradation intermediates were detected to propose a possible DMAC oxidation pathway in the ECO system. This work provides a deep insight into the quantitative analysis of the role of multiple oxidation reactions mechanism and the design of efficient electrochemical advanced oxidation technology for recalcitrant organic pollutant removal.
一种高效的电解催化臭氧（ECO）工艺被开发用于 N，N-二甲基乙酰胺（DMAC）的降解。在广泛的 pH 值范围 3.0-10.0 内，ECO 工艺降解 DMAC 的伪一级速率常数（k）比臭氧化和电解工艺的速率常数高 1.73-19.09 倍。有趣的是，我们发现，在初始 pH 值为 3.0 时，ECO 体系中 O 可以通过自由基链机制从臭氧分解中产生，而不是通过单价还原 O 产生。随后，HO 可以分别与从铁阳极释放的 Fe 和曝气的 O 参与芬顿样和过氧单烷反应。因此，非凡的 DMAC 去除效率主要是由于通过均相催化臭氧化、芬顿样和过氧单烷在 ECO 体系中的多种反应，更多地生成 OH 所致。重要的是，根据一系列捕获实验定量评估了 ECO 体系中各种初始 pH 值下涉及反应的作用。结果表明，溶液 pH 值可以显著影响各种反应的贡献，并改变 ECO 体系中多种反应的反应机制。最后，检测到降解中间产物，提出了 ECO 体系中 DMAC 氧化途径的可能途径。这项工作深入了解了定量分析多氧化反应机制的作用以及设计用于去除难降解有机污染物的高效电化学高级氧化技术。
