Electrochemical degradation of the antibiotic metronidazole in aqueous solution by the Ti/SnO₂–Sb–Ce anode

Metronidazole (MNZ) is an antibiotic pollutant with a high occurrence in the ambient medium. In this study, the anode material Ti/SnO₂–Sb–Ce prepared in the lab was employed to investigate the feasibility of the electrochemical process to treat antibiotic in wastewater. The result showed that metronidazole could be effectively removed using Ti/SnO₂–Sb–Ce. The degradation efficiency of 88% was obtained under the current density 1.6 mA cm⁻², pH=5.6 (not adjusted), electrolyte (Na₂SO₄) concentration of 0.2 M for electrolysis 2 h. The removal percentage was higher by 17% compared with the control when the bare Ti was applied. Meanwhile, the energy consumption on Ti/SnO₂–Sb–Ce was about one-seventh of that on Ti. The characterization of the material was conducted by the thermal field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectrometer (EDS) and cyclic voltammetry (CV). The Ti/SnO₂–Sb–Ce anode displayed compact, multi-porous morphology and good redox reversibility. The influencing factors such as current density, pH, concentration of Na₂SO₄, initial MNZ concentration were studied to obtain main factors and optimum conditions. In addition, a preliminary study on the mechanism of the electro-oxidation was carried out. The results demonstrate that chemisorbed oxygen has a dominant role in MNZ removal. Copyright © 2013 Taylor & Francis.