Deep oxidation of norfloxacin by the electrochemical enhanced heterogeneous catalytic oxidation: The role of electric field and reaction optimization

In this study, electrochemical (EC G-G : graphite anode and cathode, EC I-G : iron anode and graphite cathode) enhanced heterogeneous activation of peroxymonosulfate (PMS) by CoFe 2 O 4 nanoparticles for the degradation of norfloxacin (NOR) in water was investigated. Although a higher NOR removal efficiency was achieved in EC I-G /CoFe 2 O 4 /PMS system, the generation of Fe 3+ had resulted in the deposition of iron mud and affect the recovery of CoFe 2 O 4 . Under the optimum reaction conditions of CoFe 2 O 4 /PMS system, the final removal efficiency of NOR did not show significant difference in EC G-G /CoFe 2 O 4 /PMS system (96.0%) and CoFe 2 O 4 /PMS system (95.5%), but the value of apparent rate constant significantly increased in EC G-G /CoFe 2 O 4 /PMS system (0.21 min −1 ) compared with CoFe 2 O 4 /PMS system (0.11 min −1 ). Similar NOR degradation pathways were obtained in these two systems, and the TOC removal efficiency in EC G-G /CoFe 2 O 4 /PMS system (28.8%) is almost as low as CoFe 2 O 4 /PMS system (26.0%). Therefore, it can be proposed that the applied electric field through active electrodes can accelerate the reaction of heterogeneous catalytic oxidation, but does not participate much in NOR degradation. However, the TOC removal efficiency (30 min) could be reached 68.7% as the mass ratio of PMS to CoFe 2 O 4 increased to 5:1 (250 mg L −1 : 50 mg L −1 ). The EC G-G /CoFe 2 O 4 /PMS system is a promising low-cost technique for efficient mineralization of antibiotics in wastewater.