Activation of peroxymonosulfate with CuCo2O4@kaolin for the efficient degradation of phenacetin

CuCo 2 O 4 @kaolin was successfully synthesized by a sol-gel method and used as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the degradation of phenacetin (PNT). The results demonstrated that 10 mg/L PNT was completely decomposed by 1 mM PMS activated with 0.1 g/L CuCo 2 O 4 @kaolin within 15 min at initial pH 7. CuCo 2 O 4 @kaolin exhibited the best excellent catalytic performance among the tested catalysts, and the pseudo-first-order rate constants of PNT degradation were CuCo 2 O 4 @kaolin (0.40 min −1 )   >   CuCo 2 O 4 (0.22 min −1 )   >   Co 3 O 4 @kaolin (0.10 min −1 )   >   CuO@kaolin (0.08 min −1 )   >   kaolin (0.02 min −1 ). CuCo 2 O 4 @kaolin also possessed superior stability, and the degradation efficiency of PNT declined from 100% in the first round to 80% in the fourth round. Nevertheless, a simple calcinating treatment (20 min) after the third round could restore its catalytic activity substantially and 95% removal of PNT was realized, 15% higher compared to without treatment. OH, SO 4 − , and 1 O 2 were the reactive oxygen species driving the PNT degradation. Based on the results mentioned above, characterizations of CuCo 2 O 4 @kaolin, and intermediates of PNT degradation, the possible pathways and underlying mechanisms of the PNT degradation in the CuCo 2 O 4 @kaolin/PMS system were deduced. CuCo 2 O 4 @kaolin/PMS had a universal degradation potential toward various organic pollutants, and the degradation efficiencies of sulfisoxazole, p -nitrophenol, chloramphenicol, and 2,4,6-Trichlorophenol reached 95–100% within 5–45 min. Thus, this work provides a novel and efficient PMS activator through an eco-friendly synthetic route, and it may be put into practice to degrade organic matter in wastewater.