Electrochemical advanced oxidation process of Phenazopyridine drug waste using different Ti-based IrO2-Ta2O5 anodes

Electrochemical degradation of a resistant pharmaceutical, Phenazopyridine hydrochloride (PhP), was evaluated on three different dimensionally stable anodes. The main objective of this study was to investigate the catalytic performance of the three Ti-based multilayer IrO₂/Ta₂O₅ coated anodes which were made up by thermal decomposition method. The effect of operative parameters including current intensity (mA), initial pH of the solution, initial concentration of PhP (mg L⁻¹) and electrolysis time were investigated comprehensively. This comparative study demonstrated that PhP mineralization was occurred consequently on the Ti/IrO₂-Ta₂O₅ (70–30) and Ti/IrO₂-Ta₂O₅ (50–50) electrodes rapidly but it was much slower on the Ti/IrO₂-Ta₂O₅ (30–70) electrode. The performance of the electrodes revealed that the percentage of anodic materials alters the PhP degradation rate. The developed electrodes were characterized by scanning electronic microscope and energy dispersive x-ray spectroscopy. Cyclic voltammetry and electrochemical impedance spectroscopy studies were performed to investigate the efficiency of the electrodes. Decolorization of Php samples were carried out with UV-Vis spectroscopy. Furthermore, complete mineralization of PhP on Ti/IrO₂-Ta₂O₅ (70–30) was confirmed by total organic carbon (TOC) analysis. The TOC results have shown higher mineralization of PhP (72.2%) in 180 min of electrolysis. Moreover, the intermediates were identified during electrochemical degradation of PhP by GC-MS.