The regulation of generation rate facilitates the win-win of ROS yield and utilization efficiency in heterogeneous persulfate catalytic oxidation system

Heterogeneous catalytic oxidation is one of the most effective methods to degrade various and complex organic pollutants in aqueous solution. Increasing reactive oxygen species (ROS) yield has always been the main objective to improve the oxidation efficiency. However, the mass production of ROS in a short time is inevitably faced with self-quenching and ineffective consumption. Herein, Cu-based composite oxides (CuOMOx) (M = Ca, Mg, Zn, Mn) were synthesized and used for catalytic activation of permonosulfate (PMS). Although the introduction of unreducible metal oxides significantly improved the activation efficiency of PMS, the abnormal phenomenon of lower substrate degradation efficiency and PMS stoichiometry appeared. The underlying mechanism is that the rapid production of ROS results in a mismatch of the production/effective consumption ratio, which causes massive ROS disappeared naturally before attacking the substrate. In this scenario, reasonable regulation of ROS generation rate by phosphate addition improved the utilization efficiency of ROS without affecting its yield. Our finding is beneficial to achieve a win-win situation of ROS yield and utilization efficiency in heterogeneous catalytic oxidation systems.

Automated summary

Cu-based composite oxides (CuOMOx) were synthesized and used as catalysts to activate permonosulfate (PMS) for the degradation of complex organic pollutants. The addition of phosphate was effective in regulating the generation rate of reactive oxygen species (ROS), improving their utilization efficiency, and achieving a win-win situation of ROS yield and utilization efficiency in heterogeneous catalytic oxidation systems.