Catalytic Ozonation Mechanism of Norfloxacin Wastewater Using Cu-Cufe2o4 : Oxygen Vacancies Initiate Free Radical and Non-Free Radical Coupling Reactions

CuFe2O4 is often used as a catalyst for wastewater treatment due to easy magnetic recovery, environmental friendliness and low preparation cost, but its active sites were less and electrical conductivity and electron transfer efficiency were low. In order to improve the catalyst’s activity, Cu-CuFe2O4 (CCFO) was prepared by one-step solvothermal method and its oxygen vacancies (OV ) content was regulated by cetyl trimethyl ammonium bromide (CTAB). The CCFO microstructures were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) and the catalytic ozonation degradation mechanisms of Norfloxacin (NOR) were explored. The results showed that CCFO catalyst had porous microsphere structure with good dispersibility and high magnetic recovery rate. Removal efficiency of NOR was highest (81.58%) after 60 min of catalytic ozonation by using CCFO with 0.05 g CTAB as catalyst, and the first-order reaction kinetics constant was 0.03967 min-1 . Low content of CTAB significantly increased the OV content of CCFO , and the resulting OV provided the generation sites for surface hydroxyl groups and the active sites of adsorption and decomposition for O3 , and triggered ·O2- and 1O2 as main active oxygen species. The synergistic redox cycles of Fe2+ /Fe3+ and Cu0 /Cu2+ accelerated catalytic ozonation of NOR by defluorination, naphthyridine ring-opening and piperazine ring-opening