Degradation of cephalexin by persulfate activated with magnetic loofah biochar: Performance and mechanism

Antibiotic contamination has become a serious environmental problem and much attention has been paid to its purification. The sulfate radical (SO 4 − ) based advanced oxidation processes (AOPs) exhibited significant potential in the treatment of antibiotics. In this study, the magnetic biochar (Fe 2 O 3 @LBC) derived from loofah was prepared to activate persulfate (PS) for cephalexin (CEX) degradation. Under the optimal conditions, 73.9% of CEX was removed in the Fe 2 O 3 @LBC/PS system. Free radicals quenching experiments and electron paramagnetic resonance (EPR) analysis revealed that HO and SO 4 − were responsible for the degradation of CEX. The C-OH of the catalyst played a crucial role in the degradation process. In addition, the conversion between Fe 3+ and Fe 2+ enhanced the degradation of CEX by producing SO 4 − . The degradation performance of other antibiotics and CEX in different water matrices indicated the broad adaptability and applications of Fe 2 O 3 @LBC. The main intermediates and the possible transformation pathways were proposed. These results provided a potential insight into biochar based catalysts for the degradation of antibiotics by activation of persulfate.