A novel electrochemical cathode based on sea urchin-like NiO/Co3O4 composite inducing efficient Fenton-like process for levofloxacin degradation

Abstract

A sea urchin-like NiO/Co3O4 composite cathode was synthesized by two-step hydrothermal in-situ growth method and a Fenton-like process inducing two-electron oxygen reduction reaction (ORR) was established to degrade levofloxacin (LEV) in this paper. NiO/Co3O4 exhibited higher specific surface area and better electrical conductivity comparing with NiO or Co3O4, indicating an excellent synergistic effect between NiO and Co3O4. Moreover, NiO/Co3O4 cathode could effectively degrade LEV wastewater, the removal efficiency could reach 77.8% after 120 min and the corresponding COD removal efficiency was 41.0%. Further studies showed that the effective conversion of Co(Ⅱ)/Co(Ⅲ) and Ni(Ⅱ)/Ni(Ⅲ) occurred on the electrode surface, which promoted the generation of •OH. Finally, a possible degradation pathway of LEV involved defluorination, deamination, demethylation and other processes was proposed. In short, the research could provide important reference for solving electrochemical problems related to electrocatalytic ORR and Fenton-like degradation of antibiotic wastewater.