Electrochemical oxidation of caprolactam wastewater by a SnO2-Sb electrode with reduced TiO2-xN interlayer:Electrode characterization, environmental impact factors and degradation pathways.

High performance anode materials are one of the key factors affecting organic degradation. This study focused on the antimony tin oxide (ATO) electrode with the reduced TiO2-xN interlayer(TiON) as the interlayer. The surface and cross sections analysis of the TiON interlayer and ATO coatings indicates that TiON offers a larger surface area and increased contact points, facilitating greater immersion of precursors into the tube body and providing additional nucleation sites for ATO nanoparticles, whereas a smoother more compact surface contributes to the stability of the electrode. As for the interlayer, TiON provided TM/TiON/ATO with greater electrochemical activity, while preserving lower charge transfer resistance. Analysis of the effect of initial electrolyte and CPL concentrations on degradation efficiency, and the contribution of •OH and Cl• in a Cl- containing environment was analyzed. Intermediates were identified using density functional theory (DFT) computations and (Gas chromatography-mass spectrometry) GC-MS. The electrocatalytic oxidation applying TM/TiON/ATO in this work is a promising method to efficient elimination of CPL.