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.
A sensitive monoclonal antibody-based enzyme monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) was developed to detect bifenthrin in a chemical soil barrier for termite control. LBc ((2-methyl[1,1-biphenyl]-3-methoxy) carbonyl propionic acid) was conjugated to bovine serum albumin (BSA) for producing monoclonal antibody. After optimization, the IC 50 and limit of detection (LOD, IC 10 ) were 0.05 mg L − 1 and 0.004 mg L − 1 , respectively. The sensitivity was improved 40-fold compared to polyclonal antibody-based ELISA reported earlier. No cross-reactivity was measured for the other analogues such as cyhalothrin, cyhalothric acid, cypermethrin, deltamethrin, fenpropathrin, fenvalerate, ethofenprox and tetramethrin except 2-methyl-3-biphenylmethyanol. Spiked recoveries were between 83.5% and 104.7% for the detection of bifenthrin in loess, red soil and black soil. All the relative standard deviations (RSDs) were less than or equal to 15.0%. Moreover, the ELISA for authentic samples showed reliability and high correlation with gas chromatography. The developed ELISA is an alternative tool for simple, sensitive and accurate monitoring of bifenthrin in chemical soil barriers.