Interfacial Bonding of Co3o4 and Oxygen Vacancies Engineering on Zno Induced Efficient Peroxymonosulfate Activation and Pollutants Degradation

Abstract

A heterojunction of trace Co3O4 bonded on oxygen vacancies (OVs)-rich ZnO surface (OVs-ZnO/Co3O4) was synthesized via defect-assisted method to promote peroxymonosulfate (PMS) activation and pollutants removal. Experiments and theoretical calculations demonstrated that electrons could efficiently transfer from OVs-ZnO to Co3O4. OVs-ZnO and Co3O4 played different roles in activating PMS. PMS was easily adsorbed on the OVs-ZnO to form PMS* complex and mediate electron transfer to oxide ciprofloxacin (CIP), whereas, the Co3O4 facilitated breakup of peroxide bond to produce radicals. The optimized OVs-ZnO/Co3O4 heterojunction with Co content of 1.34% exhibited good PMS decomposition ability (94.2% in 30 min) compared to unmodified ZnO (24.2%), stability and anti-interference feature in removing CIP, 96.9% CIP (10 ppm) and 79.6% of total organic carbon were removed in 30 min. Moreover, the OVs-ZnO/Co3O4 achieved 91.2% CIP removal ratio with 1.0 mM PMS via a flow-through device in 180 min. This study proposes a new strategy to enhance PMS activation of ZnO and provides new viewpoint in PMS activation way.

Keywords: ZnO, Oxygen vacancy, trace Co3O4, peroxymonosulfate, Ciprofloxacin