Metronidazole and Cephalexin degradation by using of Urea/TiO2/ZnFe2O4/Clinoptiloite catalyst under visible-light irradiation and ozone injection

Abstract

Cephalexin (CEX) and metronidazole (MNZ) degradationwere photodegraded using the synthesized Urea/TiO2/ZnFe2O4/-Clinoptiloite catalyst under visible light irradiation. Diffuse reflectance ultraviolet-visible spectroscopy (UV-VisDRS) and photoluminescence (PL) analysis approved themodification of TiO2 byUrea and ZnFe2O4 compounds increased the absorption edge of catalyst to 590 nm and decreased the electron-hole recombination rate. The results showed the degradation efficiencies of ozonation process for the metronidazole and cephalexin removal were obtained 36% and 39%, respectively. The photocatalyst activity of Urea/TiO2/ZnFe2O4/Clinoptiloite (Zeolite) under visible light irradiation was determined 70% for metronidazole and 74% for cephalexin degradation. Furthermore, the combination of ozonation process and photocatalyst degradation under visible light irradiation showed high potential for the antibiotics degradation (94% for metronidazole and 95% for cephalexin) due to the increase in the generation of reactive species and synergistic effect between photocatalysis and ozonation processes. The response surfacemethodology (RSM) results revealed the removal efficiency of both pollutants were highly dependent on pH, irradiation time, catalyst concentration and initial antibiotics concentration. First order kinetics model descripted the degradation process and the rate constants were 0.0196 and 0.0243 min(-1) for the metronidazole and cephalexin removal, respectively.