Multi-dimensional induction and analysis of singlet oxygen oxidation in persulfate-based catalytic oxidation systems

As a typical non-free radical oxidation mechanism in persulfate-based catalytic oxidation system, 1O2 has received extensive attention and research. 1O2 has been found in alkali activation, reagent activation, and heterogeneous catalyst (metal-based and metal-free catalysts) activation. At present, there is no fixed standard and model for the study of 1O2, coupled with the diversity of reaction systems and the limitation of analysis means, there are widespread controversies in the generation, identification, and derivative mechanism of 1O2. Herein, we first summarized the evolutionary pathways of 1O2 in persulfate catalytic oxidation system. Then arranged and compared the commonly used 1O2 identification techniques at present. Finally, the general controversies and main challenges of 1O2 oxidation were listed. This work could assist researchers to quickly grasp the background knowledge of 1O2 oxidation in persulfate catalytic oxidation system, and is expected to provide a direction for further exploration of 1O2 oxidation.