Enhanced peroxymonosulfate (PMS) activation process mediated by vanadium modified CoO catalyst for rapid degradation of organic pollutants: Insights into the role of V

Abstract

Developing the transition metal catalysts with high reactivity for the sulfate radical (SO4－·) based advanced oxidation processes (SR-AOPs) has been attracting numerous attentions. To improve the peroxymonosulfate (PMS) activation process mediated by Co-based catalysts, a vanadium-cobalt bimetallic catalyst (V@CoO) was fabricated by modification vanadium through a simple solvothermal method. The pollutants degradation experiments showed that the obtained V@CoO exhibited much higher performance on PMS activation (5.55–8.33 times larger of apparent rate constants) than pure CoO, and the V@CoO/PMS system could quickly degrade various organic contaminants within 5 min under the attack of both radicals (SO4－·and O2－·) and non-radicals (1O2). The density functional theory (DFT) calculations and electrochemical tests revealed that the enhancing mechanism of V modification involved four aspects: (i) promoting the PMS adsorption on the surface of V@CoO; (ii) enhancing the electron transfer efficiency between V@CoO and PMS; (iii) activating PMS with V3+ and V4+ species; (iv) accelerating the circulation of Co2+ and Co3+, leading to the promotion on the production of reactive oxygen species (ROS). Furthermore, the V@CoO/PMS system also exhibited satisfactory stability in a broad pH range and good efficiency in the presence of co-existing components (HCO3−, NO3−, PO43−, Cl− and HA) in water. This study will provide new insights to designing high-performance, environment-friendly bimetal catalysts and some basis for the remediation of organic contaminants with SR-AOPs.