Efficient electrochemical degradation of phenazopyridine hydrochloride using boron-doped diamond electrodes
摘要
The electrochemical degradation of phenazopyridine hydrochloride (PhH), a recalcitrant pharmaceutical contaminant, was systematically investigated using boron-doped diamond (BDD) film electrodes as anodes. The effects of current density (10–40 mA cm⁻2), electrolyte composition (Na2SO4, NaCl, and Na2CO3), and initial pH (3–11) on degradation efficiency and mineralization were evaluated. Process performance was assessed through solution decolorization, ultraviolet–visible spectroscopy, and total organic carbon (TOC) analysis. Under optimized conditions (0.1 M Na2SO4, 30 mA cm⁻2, pH 7), complete decolorization and more than 80% TOC removal were achieved for an initial PhH concentration of 30 mg L⁻1. Notably, a degradation efficiency of 82.9% was obtained within 30 min of treatment, demonstrating rapid performance compared with other advanced oxidation studies where similar removal levels generally require substantially longer reaction times or more complex catalytic systems. The results indicate that PhH oxidation proceeds predominantly via non-selective hydroxyl radicals generated at the BDD surface, with degradation efficiency strongly dependent on current density and electrolyte identity. Durability tests demonstrated excellent electrode stability, with degradation efficiencies exceeding 95% over ten consecutive treatment cycles. In contrast to prior PhH studies largely focused on photo-assisted advanced oxidation processes under idealized conditions, this work provides a systematic assessment of BDD-based electrochemical oxidation in a simulated pharmaceutical wastewater matrix, emphasizing rapid mineralization efficiency, electrolyte effects, and electrode reusability. These findings highlight the suitability of BDD electrodes as robust anode materials for advanced electrochemical treatment of pharmaceutical wastewater.