Electrochemical degradation of ofloxacin using PbO2/Pb-based lead acid battery electrode: Parametric optimization and kinetics study

Abstract

In this study, PbO2/Pb-based electrode used in commercial lead-acid battery was applied for electrochemical oxidation (ECO) of ofloxacin (OFX) in aqueous phase. Surface topography of PbO2/Pb electrode material was analysed to access surface morphology composed of Pb and oxygen elements of PbO2 through scanning electron microscopy analysis and energy dispersive X-ray analysis. Electrochemical characterization like linear sweep voltammetry analysis, oxygen evolution potential determined as 1.25 V for PbO2/Pb electrode. A high oxidation peak current obtained in cyclic voltammetry analysis suggest that oxidation of OFX with help of produced hydroxyl (●OH) reactive species. Parametric optimization of various process parameters in ECO process was conducted to determine maximum efficacy of process. Maximum OFX removal (85 %) was obtained under the optimum conditions of (initial concentration of OFX:100 ppm, current density: 50 mA/cm2, Na2SO4 electrolyte concentration: 0.1 M Na2SO4 and pH:4). Maximum Chemical oxygen demand (COD) removal (65 %) is obtained when 18 kWh (kg COD removed) −1 of electrical energy was used in ECO process for OFX degradation. Reusability test conducted for used PbO2/Pb electrode indicates that the electrode is stable and can be used repeatedly up to 5 repeated cycles with a minimum 20 % loss in removal %.