Electrochemical removal of amoxicillin using a Cu doped PbO2 electrode: Electrode characterization, operational parameters optimization and degradation mechanism

Abstract

This work investigated the electrochemical degradation of amoxicillin (AMX) in aqueous solution with Cu-PbO₂ electrode. The main influence factors on the degradation of AMX, such as Na₂SO₄ concentration, initial AMX concentration, current density and initial pH value, were analyzed in detail. Under the optimal conditions, the removal rates of AMX and chemical oxygen demand (COD) reached 99.4% and 46.3% after 150 min treatment. The results indicated that the electrochemical degradation of AMX fitted pseudo-first-order reaction kinetics. Compared with undoped PbO₂ electrode, Cu-PbO₂ electrode had a smaller crystal size, more proportion of hydroxyl oxygen species, greater AMX and chemical oxygen demand (COD) removal efficiency, higher average current efficiency (ACE) and lower electrical efficiency per log order (EE/O). Electrochemical oxidation using Cu-PbO₂ electrodes was an effective way to eliminate amoxicillin in aqueous solution. Moreover, a possible degradation pathway including ring open and mineralization was proposed by intermediate products determined by GC-MS method. This paper could provide basic data and technique reference for the amoxicillin wastewater pollution control.

Keywords: Amoxicillin; Cu-doped PbO(2) electrode; Degradation mechanism; Electrochemical degradation.