CoFe2O4@BC as a heterogeneous catalyst to sustainably activate peroxymonosulfate for boosted degradation of enrofloxacin: Properties, efficiency and mechanism

The large residual amounts and long-term exposure to fluoroquinolones (FQs) pose severe threats to the environment and human health. In this study, a carbon-based metal material (CoFe2O4@BC) was synthesized via a facile one-step hydrothermal method to activate peroxymonosulfate (PMS) for eliminating enrofloxacin (ENR) greater than 96 % in five cycles. The morphology analysis revealed that the CoFe2O4 nanoparticles possessed the spinel structure and were homogenously dispersed within the BC tubular pores, resulting in a significantly enhanced specific surface area (211.19 m2/g). The reaction mechanism was demonstrated that a heterogeneous process occurred on the catalyst surface and the active sites of Co, Fe, and C facilitated the co-activation of PMS by enabling electron transfer to accomplish redox cycles. Radicals (SO4− and OH) were more predominant in the CoFe2O4@BC/PMS system than nonradicals (1O2 and high-valent metal-oxo species). Through density functional theory calculations, three-dimensional excitation-emission matrix fluorescence spectra analyses and toxicity assessment software tool analyses, ENR was degraded into twelve intermediates and ultimately mineralized into CO2 and H2O, resulting in a reduction of overall toxicity. This study provides an economically feasible and magnetically separable catalyst for PMS activation, presents a novel approach for environmentally friendly and efficient removal of aqueous antibiotics.