Efficient degradation of amoxicillin by scaled-up electro-Fenton process: Attenuation of toxicity and decomposition mechanism

In this work, a scaled-up electro-Fenton (EF) system was performed on the treatment of amoxicillin (AMX) wastewater. The effects of operational parameters on AMX degradation efficiency were investigated, such as Fe²⁺ concentration, pH, applied current (mA) and initial AMX concentration. Kinetic analysis exhibited the degradation process followed the First-order kinetic model. Box-Behnken design (BBD) was applied here to determine and analyze the optimum operating condition. Up to17.68 mg•L⁻¹ of H₂O₂ could be in situ generated in 120 min without external O₂ supply and reusability of the electrodes were analyzed. Moreover, a degradation mechanism with hydroxyl radicals (•OH) as dominant oxidant was proposed. UPLC-MS analysis was performed to identify oxidation intermediates and thus a reasonable degradation pathway of AMX was speculated. Acute toxicity assessment showed a 50% decrease in bio-toxicity of the treated effluent. The EF system provided a new insight into the effective pretreatment of antibiotic wastewater.