Ti–Sn–Ce/bamboo biochar particle electrodes for enhanced electrocatalytic treatment of coking wastewater in a three-dimensional electrochemical reaction system

Abstract Ti–Sn–Ce/bamboo biochar (BC) was prepared and made use of particle electrodes in a three-dimensional electrochemical reaction system (3DERs) for efficient treatment of the coking wastewater. Ti–Sn–Ce/BC was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), which indicated a significant amount of Ti–Sn–Ce oxides existed on the surface and in the interior of the BC. With an optimum electrolysis time of 150 min and a current density of 30 mA/m2, the removal rates of COD and DOC in coking wastewater reached 92.91% and 74.66%, respectively, and UV254 decreased from 7.72 to 1.22 cm−1. The addition of Ti, Sn and Ce significantly improved the treatment capacity of the BC particle electrodes for coking wastewater. The three-dimensional fluorescence spectra and GC-MS results of the coking wastewater before and after treatment in the 3DERs indicated that the macromolecular toxic substances in the coking wastewater were degraded into low-toxic organic substances, and most of the soluble organic compounds were degraded and transformed. Furthermore, the addition of Ti, Sn and Ce enhanced the efficacy of the electrooxidation, electro-adsorption and electrocatalytic properties of the BC particle electrodes, which improved the treatment effect on coking wastewater in the 3DERs. Moreover, the addition of Ce helped the Ti–Sn–Ce/BC particle electrodes to produce more ·OH and improved the electro-oxidation performance and electrocatalytic activity of the electrocatalyst. This study provided a possibility of basic research for the engineering practice of coking wastewater treatment by using a method of electrochemical oxidation.