College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, PR China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
Sci Total Environ. 2021 Apr 15;765:142794. doi: 10.1016/j.scitotenv.2020.142794. Epub 2020 Oct 8.
Nonradical persulfate oxidation processes have emerged as a new wastewater treatment method due to production of mild nonradical oxidants, selective oxidation of organic pollutants, and higher tolerance to water matrixes compared with radical persulfate oxidation processes. Since the case of the nonradical activation of peroxydisulfate (PDS) was reported on CuO surface in 2014, nonradical persulfate oxidation processes have been extensively investigated, and much achievement has been made on realization of nonradical persulfate activation processes and understanding of intrinsic reaction mechanism. Therefore, in the review, nonradical pathways and reaction mechanisms for oxidation of various organic pollutants by PDS and peroxymonosulfate (PMS) are overviewed. Five nonradical persulfate oxidation pathways for degradation of organic pollutants are summarized, which include surface activated persulfate, catalysts-free or catalysts mediated electron transfer, O, high-valent metals, and newly derived inorganic oxidants (e.g., HOCl and HCO). Among them, the direct oxidation processes by persulfate, nonradical based persulfate activation by inorganic/organic molecules and in electrochemical methods is first overviewed. Moreover, nonradical based persulfate activation mechanisms by metal oxides and carbon materials are further updated. Furthermore, investigation methods of interaction between persulfate and catalyst surface, and nature of reactive species are also discussed in detail. Finally, the future research needs are proposed based on limited understanding on reaction mechanism of nonradical based persulfate activation. The review can offer a comprehensive assessment on nonradical oxidation of organic pollutants by persulfate to fill the knowledge gap and provide better guidance for future research and engineering application of persulfate.
非自由基过硫酸盐氧化工艺因其产生温和的非自由基氧化剂、对有机污染物的选择性氧化以及相对于自由基过硫酸盐氧化工艺对水基质更高的耐受性而成为一种新的废水处理方法。自 2014 年报道在 CuO 表面非自由基活化过二硫酸盐 (PDS) 以来，非自由基过硫酸盐氧化工艺得到了广泛的研究，并在实现非自由基过硫酸盐活化工艺和理解内在反应机制方面取得了很大的成就。因此，在综述中，概述了 PDS 和过一硫酸盐 (PMS) 氧化各种有机污染物的非自由基途径和反应机制。总结了五种非自由基过硫酸盐氧化途径来降解有机污染物，包括表面活化过硫酸盐、无催化剂或催化剂介导的电子转移、O、高价金属和新衍生的无机氧化剂（例如 HOCl 和 HCO）。其中，首先综述了过硫酸盐的直接氧化过程、无机/有机分子和电化学中非自由基基过硫酸盐的活化。此外，还进一步更新了金属氧化物和碳材料中非自由基基过硫酸盐的活化机制。此外，还详细讨论了过硫酸盐与催化剂表面相互作用的研究方法以及反应性物质的性质。最后，根据对非自由基基过硫酸盐活化反应机制的有限理解，提出了未来的研究需求。该综述可以对过硫酸盐氧化有机污染物的非自由基氧化进行全面评估，以填补知识空白，并为过硫酸盐的未来研究和工程应用提供更好的指导。
