Preparation and electrochemical treatment application of Ti/Sb–SnO2-Eu&rGO electrode in the degradation of clothianidin wastewater

Abstract

This work investigated the preparation of Ti/Sb–SnO2 electrode co-doped with graphene and europium and the electrochemical degradation of clothianidin in aqueous solution with Ti/Sb–SnO2-Eu&rGO electrode. The physicochemical properties of different electrodes were characterized by using the scanning electron microscopy, X-ray diffraction, oxygen evolution potential and cyclic voltammetry tests. The results indicated that the Ti/Sb–SnO2-Eu&rGO electrodes have a compact structure and fine grain size and have a higher oxygen evolution overpotential than Ti/Sb–SnO2-None, Ti/Sb–SnO2-Eu and Ti/Sb–SnO2-rGO electrodes. Among the four electrodes, the Ti/Sb–SnO2-Eu&rGO electrode showed the highest efficiency and was chosen as the experimental electrode. The main influence factors on the degradation of clothianidin, such as initial pH, electrolyte concentration, current density and initial concentration of clothianidin, were analyzed. The results showed that the removal rate of clothianidin can reach 96.44% under the optimal conditions for 120 min treatment. Moreover, a possible degradation pathway including the fracture of internal bonds of clothianidin such as the N–N bond, the C–N bond that connects nitroguanidine to the thiazole ring and mineralization was elucidated by intermediate products identified by HPLC-MS method and Fourier transform infrared spectroscopy (FTIR). This paper introduces the Ti/Sb–SnO2-Eu&rGO electrode into an electrocatalytic degradation system and could provide basic data and technique support and guidance for the clothianidin wastewater pollution control.