Electrochemical oxidation of Rhodamine B in dye wastewater by a novel boron-doped diamond electrode: parameter optimization and degradation mechanism

The escalating pollution of water resources, predominantly attributable to the printing and dyeing industry, has garnered increased attention towards the treatment technology for such wastewater. In this study, an innovative boron-doped diamond electrode was employed for the removal of Rhodamine B (RhB) in dye wastewater through electrochemical oxidation (EO). The optimization of process parameters was achieved through a single-factor experiment. The degradation pathway of RhB was examined using Density functional theory calculations and Liquid chromatography-mass spectrometry. The results showed that when pH = 7, j = 40 mA∙cm−2, c(Na2SO4) = 0.035 mol·dm−3, and c0(RhB) = 50 mg·dm−3, the removal efficiency could reach 93.83% at 60 min. The EO process of RhB adhered to pseudo-first-order kinetics. The degradation process of RhB primarily encompasses several stages: deethylation reaction, destruction of the conjugated structure, decolorization, degradation reaction, and ring-opening mineralization reaction. This study offers a theoretical foundation for the practical implementation of BDD electrode electrochemical oxidation technology in dye wastewater treatment.