Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, CNRS, Clermont Auvergne INP SIGMA Clermont, F-63000 Clermont-Ferrand, France.
École Nationale Supérieure de Chimie de Rennes, Université Rennes, CNRS, ISCR-UMR6226, F-35000 Rennes, France.
Molecules. 2021 Sep 22;26(19):5748. doi: 10.3390/molecules26195748.
The key role of trivalent manganese (Mn(III)) species in promoting sulfate radical-based advanced oxidation processes (SR-AOPs) has recently attracted increasing attention. This review provides a comprehensive summary of Mn(III) (oxyhydr)oxide-based catalysts used to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) in water. The crystal structures of different Mn(III) (oxyhydr)oxides (such as α-MnO, γ-MnOOH, and MnO) are first introduced. Then the impact of the catalyst structure and composition on the activation mechanisms are discussed, as well as the effects of solution pH and inorganic ions. In the Mn(III) (oxyhydr)oxide activated SR-AOPs systems, the activation mechanisms of PMS and PDS are different. For example, both radical (such as sulfate and hydroxyl radical) and non-radical (singlet oxygen) were generated by Mn(III) (oxyhydr)oxide activated PMS. In comparison, the activation of PDS by α-MnO and γ-MnOOH preferred to form the singlet oxygen and catalyst surface activated complex to remove the organic pollutants. Finally, research gaps are discussed to suggest future directions in context of applying radical-based advanced oxidation in wastewater treatment processes.
三价锰 (Mn(III)) 物种在促进基于硫酸根自由基的高级氧化过程 (SR-AOPs) 中的关键作用最近引起了越来越多的关注。本综述全面总结了用于在水中激活过一硫酸盐 (PMS) 和过二硫酸盐 (PDS) 的基于 Mn(III)（氧）氢氧化物的催化剂。首先介绍了不同的 Mn(III)（氧）氢氧化物（如 α-MnO、γ-MnOOH 和 MnO）的晶体结构。然后讨论了催化剂结构和组成对活化机制的影响，以及溶液 pH 值和无机离子的影响。在 Mn(III)（氧）氢氧化物激活的 SR-AOPs 体系中，PMS 和 PDS 的活化机制不同。例如，Mn(III)（氧）氢氧化物激活的 PMS 既可以产生自由基（如硫酸根和羟基自由基），也可以产生非自由基（单线态氧）。相比之下，α-MnO 和 γ-MnOOH 对 PDS 的激活更倾向于形成单线态氧和催化剂表面的活化配合物来去除有机污染物。最后，讨论了研究空白，以建议在废水处理过程中应用基于自由基的高级氧化技术的未来方向。
