BACKGROUND Iron (Fe)-copper (Cu) bimetallic catalysts such as CuFe2O4, CuFeO2 and CuO/Fe3O4 have been widely applied in persulfate oxidization process. Among these catalysts, CuFe2O4 has shown excellent performance in catalyzing peroxymonosulfate. However, because the catalytic effect of CuFe2O4 on persulfate (PS) is not obvious, the application of CuFe2O4 to activate persulfate has been investigated only rarely. Hence, structural modification has been applied in order to improve the catalytic activity of CuFe2O4 on persulfate. RESULT In this study, Oxygen (O)-deficient CuFe2O4 was synthesized via the hydrogen reduction method and first used to activate PS for degrading acetaminophen (APAP) in aqueous solution with low catalyst concentration of 0.3 g L-1. Results reveal that high-concentration APAP (100 mg L-1) could be efficiently removed by O-deficient CuFe2O4-activated PS, and 91% removal rate could be reached in 60 min using 0.8 g L-1 PS and 0.3 g L-1 catalyst under unadjusted pH. Dissolved O-2 and Cl(-)showed inhibitory effects on the degradation process. Radical scavenger experiments, in which methanol, tert-butyl alcohol (TBA) and nitrobenzene (NB) were used as radical trappers, indicated that SO4- and OH were the active radicals in the reaction, but the main radical was SO4-. Oxygen-deficient CuFe2O4 showed strong reduction ability and could activate PS efficiently, and the electron transfer capability was remarkably enhanced after this structural modification. CONCLUSIONS Results indicated that compared to the pristine crystal, the catalytic activity of CuFe2O4 could be improved through structural modification. Additionally, the structurally modified catalyst showed high potential to treat wastewater with high antibiotic content under mild conditions. (c) 2018 Society of Chemical Industry