Electrocatalytic oxidation of tetracycline by Bi-Sn-Sb/γ-Al₂O₃ three-dimensional particle electrode

In this work, highly efficient Bi-Sn-Sb/γ-Al₂O₃ particle electrodes were prepared for effectively degrading tetracycline. The effects of a mass ratio (Sn: Sb), the mass ration of Bi:(Sn + Sb), impregnation times, calcination temperature, and calcination time on the electrocatalytic oxidation capacity of Bi-Sn-Sb/γ-Al₂O₃ particle electrode was investigated. Conditions in which mass ratio of (Sn: Sb) = 10:1, the mass ratio of Bi:(Sn/Sb) = 1:1, impregnation times 2 h, calcination temperature 500 °C., and calcination time 3 h were considered as optimal preparation conditions for Bi-Sn-Sb/γ-Al₂O₃ particle electrode. It was cherecterized by infrared spectroscopy (IR), scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), X-Ray Diffraction (XRD), and X-ray fluorescence (XRF) techniques to conforming that the triclinic Bi₂O₃ formed in the preparation conditions has superior electrocatalytic activity. The electrocatalytic oxidation mechanism of tetracycline by Bi-Sn-Sb/γ-Al₂O₃ particle electrode is proposed by determining degradation intermediates through LC-MS detection. Electrocatalytic oxidation experiments by adding tert-butyl alcohol indicate that the formation of OH is the primary responsibility for degradating tetracycline. Electrocatalytic degradation of tetracycline at different initial concentration shows that the degradation of tetracycline meets the pseudo first-order kinetics. Results suggest that the three-dimensional electrochemical reactor with Bi-Sn-Sb/γ-Al₂O₃ particle electrodes could be an alternative for the pretreatment of antibiotic wastewater before biological treatment.