Degradation of Norfloxacin by Electrochemical Oxidation Using Ti/Sno 2 -Sb Electrode Doped with Ni or Mo

Electrochemical oxidation of NOR (norfloxacin) was first investigated on Ti/SnO 2 -Sb, Ti/SnO 2 -Sb-Ni, and Ti/SnO 2 -Sb-Mo electrodes prepared by sol-gel method. The influence of transition metal doping on the electrode performance was characterized by SEM (scanning electron microscopy), EDS (energy-dispersive spectrometer), XRD (X-ray diffraction), and LSV (linear voltammetric curve). The doping of metal elements can change the surface morphology of the electrodes and the grain size of the active layer, which affect the electrocatalytic activity of the electrode. Among these three prepared electrodes, the Ti/SnO 2 -Sb-Ni electrode has the highest oxygen evolution potential and the best removal effect on NOR. The effects of current density, the pH value, and the initial concentration of NOR on the removal of NOR by electrochemical oxidation with Ti/SnO 2 -Sb-Ni electrode were investigated. For Ti/SnO 2 -Sb-Ni electrode, the removal rate of NOR was 100% after 30 min and the removal rate of TOC was 75% after 120 min under the conditions of the current density of 20 mA cm −2 , pH of 3, initial concentration of NOR of 100 mg L −1 , and concentration of Na 2 SO 4 of 0.25 mol L −1 . The kinetic investigation showed that the oxidation of NOR on these three electrodes displayed pseudo-first-order kinetic behavior. For NOR degradation, the electrocatalytic performance of p-type metal-doped Ti/SnO 2 -Sb electrode (Ti/SnO 2 -Sb-Ni) is better than that of n-type metal-doped Ti/SnO 2 -sb electrode (Ti/SnO 2 -Sb-Mo). Graphical abstract