Efficient and stability electrochemical degradation of Bisphenol A on Ti/TiO2-NTA/PbO2-Nd anode: Mechanistic analysis

The Ti/TiO2-NTA/PbO2-Nd electrodes were fabricated using anodic oxidation and electrodeposition techniques for the electrocatalytic treatment of bisphenol A (BPA) pollutants in coking wastewater. Characterization revealed well-organized TiO2 nanotube arrays (TiO2-NTA) with a hollow structure, featuring a wall thickness of 36 nm and an inner diameter of approximately 83 nm. The TiO2-NTA interlayer restricted PbO2 growth, leading to a compact crystal structure and increased electrode surface area. Electrochemical tests showed that the Ti/TiO2-NTA/PbO2-Nd electrode outperformed Ti/TiO2-NTA/PbO2 and Ti/PbO2 electrodes, exhibiting the highest oxygen evolution potential, lowest charge transfer resistance, optimal hydroxyl radical generation, and longest service lifetime. The removal efficiencies for BPA were 95.4 % for Ti/TiO2-NTA/PbO2-Nd, 90.8 % for Ti/TiO2-NTA/PbO2, and 80.6 % for Ti/PbO2. The Ti/TiO2-NTA/PbO2-Nd electrode also achieved the lowest energy consumption at 0.157 kWh/(g·COD), a 40 % reduction compared to Ti/PbO2. The introduction of TiO2-NTA enhanced electrode stability, electron transfer, and surface area, while neodymium (Nd) doping improved oxygen evolution potential and hydroxyl radical production. Under optimized conditions, the Ti/TiO2-NTA/PbO2-Nd electrode achieved BPA removal efficiencies of 99.24 %, COD removal efficiencies of 82.77 %, and TOC removal efficiencies of 78.92 %. UV–Vis spectrophotometry, three-dimensional excitation-emission matrix fluorescence spectra (3D EEM), and gas chromatography–mass spectrometry (GC–MS) analyses revealed potential BPA degradation pathways.