Surface oxygen vacancy inducing peroxymonosulfate activation through electron donation of pollutants over cobalt-zinc ferrite for water purification

Peroxymonosulfate (PMS) activation in heterogeneous processes for pollutant degradation is a promising water purification technology. However, the existed rate limiting step greatly restrains its performance and increases the consumption of PMS and energy. Herein, we offer a new strategy to solve this problem. In this work, surface oxygen vacancy (V-O)-rich ZnFe0.8Co0.4O2.4 nanoparticles were prepared and characterized, which exhibited high activity and stability for refractory pollutant degradation with PMS activation. It was found that PMS ([O3S-O-I-O-II-H](-)) could be adsorbed and trapped by the surface oxygen vacancies in the form of O-I-Vo or O-II-Vo during the reaction. Different electron transfer pathways from Vo to different O sites of PMS was realized in the solid-liquid interface based on the generation of (OH)-O-center dot, SO4 center dot- or H-2 from PMS reduction. Pollutants were predominantly adsorbed at metal Co sites in which their electrons were captured by metal species and then transferred to the surface oxygen vacancies, achieving efficient recycling of electrons in the aqueous suspensions. This system achieves a dual-pathway degradation of pollutants and electron transfer from pollutants to PMS to produce free radicals and H-2, essentially changing the traditional concepts of pollutant removal and providing a sustainable strategy for pollutant utilization during water purification.