Highly efficient and mild electrochemical degradation of bentazon by nano-diamond doped PbO2 anode with reduced Ti nanotube as the interlayer

Abstract Anodic oxidation based on PbO2 anode has been demonstrated as the feasible approach for the decontamination of organic pollutants; however, the performance of this process is hindered by its ordinary electrochemical activity and relatively low stability. In this study, we fabricated an efficient Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND electrode with electrochemically reduced TiO2 nanotubes as the interlayer and nano-diamond as the dopant. As compared with other electrodes, the constructed Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND exhibited higher oxygen evolution overpotential, larger active area and less charge transfer resistance. Thus, the average current efficiency of 30% could be attained at 120 min with TiO2-NTs/Sb-SnO2/PbO2, which was 1.5 times higher in comparison with the typical Ti/Sb-SnO2/PbO2 electrode. It was found that the removal efficiency of COD could be increased from 49% to 69% after 120 min treatment in the presence of 10 mM Cl−1 in the electrolyte. After 6 h of electrolysis, 74% of TOC was removed and 31% and 22% of initial N was transformed into NH4+ and NO3- ions, respectively. And oxalic acid, glyoxylic acid, malonic acid and acetic acid were identified quantitatively as the intermediate products. Finally, it was estimated that the accelerated service life of Ti/TiO2-RNTs/Sb-SnO2/PbO2-ND electrode was approximately three times of Ti/Sb-SnO2/PbO2 electrode. Generally, this study is of great interest for the engineering community to design an efficient electrode material for the wastewater treatment.