The insight into effects of oxygen vacancy on the activation of peroxymonosulfate via MOF-derived magnetic CoFe2O4 for degrading organic contaminants

Herein, MOF-derived magnetic CoFe2O4 with oxygen vacancy was successfully synthesized to activate peroxymonosulfate (PMS) for the effective degradation of emerging organic contaminants. The introduction of oxygen vacancy not only increased the specific surface area of CoFe2O4, but also reduce the charge transfer resistance. The CoFe2O4 with oxygen vacancy showed low charge transfer resistance and oxidation potential. Benefitting from the existence of oxygen vacancy, the PMS could be activated quickly by CoFe2O4 to produce SO4 center dot-. As expected, developed CoFe2O4/PMS oxidation system displayed the excellent degradation ability toward various typical organic pollutants, and the organic pollutant could be mineralized into CO2, H2O and other inorganic molecules. Interestingly, both redox couples of Fe3+/Fe2+ and Co3+/Co2+ played a critical role in the PMS activation process. The SO4 center dot-, OH center dot, O-2(center dot-) and O-1(2) were major active species in the CoFe2O4/PMS system, which were responsible for the degradation of organic pollutants. Furthermore, proposed CoFe2O4/PMS oxidation system also presented a wide pH range of applicability. The existence of magnetic property was convenient for the recovery of catalyst. All in all, this study provided a promising catalyst for the activation of PMS, and obtained results injected some new insights into the research on advanced oxidation processes (AOPs).