In-situ electrodeposition of Co/Ce-MOF-derived carbon composites as anode for electrochemical degradation of ceftazidime

Abstract

Antibiotics cannot be completely removed through traditional treatment technologies, leading to their accumulation in the aquatic environment and posing a serious threat to human health. MOF-derived carbon is a promising material for the degradation of antibiotics. Herein, in this study, a novel Co/Ce-MOF electrode was rapidly prepared by one-step electrodeposition at room temperature. Then the Co/Ce-MOF electrode was carbonized to obtain MOF-derived carbon composite electrode (Co/Ce-C350Air). The ceftazidime (CAZ) degradation efficiency achieved 96.59% within 60 min under the optimum conditions ([CAZ] = 5 mg/L, [Na2SO4] = 50 mM, current density = 0.8 mA/cm2, electrode gap = 2 cm and initial pH = 5.6) and the degradation process of CAZ conformed to first-order reaction kinetics. Furthermore, the removal efficiency of CAZ maintained at 94.92% even recycling for 6 times, demonstrating the good electrochemical stability of the Co/Ce-C350Air composite anode. The synergistic effect between Co and Ce metals improved the catalytic performance and stability of the Co/Ce-C350Air electrode. Radical quenching experiments and electron paramagnetic resonance (EPR) spectra results revealed that surface hydroxyl radicals were the main active species in the degradation of CAZ. The main intermediate products were identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and the possible degradation pathway was proposed. In addition, toxicity tests with Ecological Structure Activity Relationships (ECOSAR) software results indicated that the toxicity of the intermediate products was lower than that of CAZ. This work provided a safe and effective strategy for the degradation of antibiotics in the electrochemical oxidation system.