Enhanced catalytic degradation of antibiotics by peanut shell-derived biochar-Co3O4 activated peroxymonosulfate: An experimental and mechanistic study

Abstract

A peanut shell-derived biochar-Co3O4 (Bio-Co3O4) catalyst prepared by chemical bath deposition (CBD) method exhibited excellent ofloxacin (OFL) degradation ability through a broad pH range for peroxymonosulfate (PMS) activation. The excellent properties and behavior of catalyst were studied by characterization and degradation experiments. Benefiting from the synergy of adsorption and degradation, Bio-Co3O4 composite showed much higher removal efficiency (97.3%) and larger reaction rate constant (k = 0.1411 min−1) than that of biochar or Co3O4 in presence of PMS. Mechanisms exploration suggested that dual active pathways, including singlet oxygen-dominated non-radical pathway and sulfate radical-dominated radical pathway were involved in the reaction mechanism. The graphitized structure, stable redox cycle of Co2+/Co3+ and CO groups in catalyst were mainly responsible for the generation of reactive species. Furthermore, a total of ten main intermediates were detected and OFL degradation pathways as well as catalytic mechanisms were identified and proposed in detail. Overall, our study provides a potential way to activate PMS for the effective removal of abusive antibiotics from aqueous environments.