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

Abstract 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.