Photocatalytic activation of peroxymonosulfate by Bi2WO6/Fe3O4/ZrO2 magnetic composite for degradation of cloxacillin, moxifloxacin, and azithromycin antibiotics under visible LED light irradiation

Abstract

Activating peroxymonosulfate (PMS) with an appropriate photocatalyst under visible light is a promising strategy for efficiently degrading persistent organic contaminants in various water environments. This study aimed to activate PMS using the magnetic Bi2WO6/Fe3O4/ZrO2 photocatalyst for the efficient degradation of the persistent antibiotics cloxacillin (CLX), moxifloxacin (MOX), and azithromycin (AZY) in water resources under visible LED light. The response surface methodology-central composite design (RSM-CCD) technique was employed to evaluate the interaction effects of operational parameters on photocatalytic activity. Analysis of variance (ANOVA) results indicated that pH was the most influential factor on CLX and MOX degradation, while initial antibiotic concentration significantly affected AZY photodegradation efficiency. The Bi2WO6/Fe3O4/ZrO2 + LED+PMS process could degrade 95.83 % of CLX, 96.99 % of MOX, and 98.23 % of AZY under optimal conditions. The photocatalytic mineralization rates achieved for CLX, MOX, and AZY were 85.71 %, 75.75 %, and 80.21 %, respectively. Results from the scavenging experiments indicated that superoxide radicals were primarily responsible for the degradation of CLX, MOX, and AZY. Our study showed that the magnetic Bi2WO6/ Fe3O4/ZrO2 composite is highly effective in activating PMS, facilitating the thorough degradation and mineralization of various antibiotic pollutants.