Self-synthesized heterogeneous CuFe2O4-MoS2@BC composite as an activator of peroxymonosulfate for the oxidative degradation of tetracycline

Transition metal compounds are often used as activators in advanced oxidation processes for the treatment of refractory organics. However, the problems of inter-particle agglomeration, metal ion leaching and difficulty in recycling frequently occurred, resulting in reduced activation performance and secondary pollution. In this study, biochar (BC) was prepared from agricultural waste pine cone shells, and then a self-synthesized heterogeneous CuFe2O4-MoS2@BC composite was prepared for the first time, which can be used as an activator of peroxymonosulfate (PMS) for the oxidative degradation of tetracycline (TC). Analysis techniques such as XRD, SEM, BET, FT-IR, Raman, XPS, and VSM indicated that the heterogeneous catalyst with good surface properties and catalytic stability has been successfully prepared. When different concentrations of TC were treated with 0.5 g/L CuFe2O4-MoS2@BC and 1 mmol/L PMS, the highest degradation rate could reach 99.66 % after 60 min. Under the interference of pH, common anions and humic acid in the water environment, the degradation system can still achieve high degradation efficiency, showing excellent anti-interference ability and practical applicability. The analysis of activation mechanism reveals that the three redox ion pairs Cu+/Cu2+, Fe2+/Fe3+ and Mo4+/Mo6+ simultaneously participated in the activation of PMS, realizing multi-path electron transfer. And MoS2 played an excellent co-catalysis role in promoting the cycling of the valence states of the ions. A total of 24 intermediate products was detected in the degradation process using LC-MS technology, and the possible degradation pathways for TC degradation were proposed. The self-synthesized CuFe2O4-MoS2@BC composite with high catalytic performance, stability, recyclability and low ion leaching rate has broad application prospects in the treatment of tetracycline antibiotic wastewater by activated PMS.