Activation of peroxymonosulfate by magnetic CuFe2O4@ZIF-67 composite catalyst for the study on the degradation of methylene blue

In this research, a novel magnetically recoverable composite catalyst, CuFe 2 O 4 @ZIF-67, was synthesized. CuFe 2 O 4 @ZIF-67 composite catalyst was applied to degrade methylene blue (MB) in water by activating peroxymonosulfate (PMS). The results showed that the degradation rate of MB (20 mg/L) reached 98.9% in 30 min in the 0.2-CuFe 2 O 4 @ZIF-67 (75 mg/L) + PMS (125 mg/L) system. Both electron paramagnetic resonance (EPR) studies and radical quenching experiments revealed that SO 4 − •, •OH, 1 O 2 and •O 2 − were involved in the degradation of MB. We proposed a catalytic mechanism of PMS activation by CuFe 2 O 4 @ZIF-67. With the synergistic effect of Co 3+ /Co 2+ , Fe 3+ /Fe 2+ and Cu 2+ /Cu + redox cycles, it can keep its outstanding catalytic activity. Recycling tests showed that the removal rate of MB can still be maintained above 85%, indicating that CuFe 2 O 4 @ZIF-67 has good reusability. In general, owing to its reusability and excellent catalytic activity, the CuFe 2 O 4 @ZIF-67 composite catalyst has a good application prospect in water pollution control.