MoS2 nanosheets vertically aligned on biochar as a robust peroxymonosulfate activator for removal of tetracycline

MoS2 nanosheets were vertically aligned on the surface of biochar calcined from Chinese cabbage and applied to efficiently activate peroxymonosulfate (PMS), which promoted the removal of tetracycline (TC) in aqueous solutions. In heterogeneous PMS systems, the composites with different mass ratios of biochar and MoS2 all exhibited excellent catalytic efficiencies for TC removal. Specially, the extraordinary catalytic efficiency of BC300-MoS2-1 was achieved through the synergistic radical (•OH, SO4•−, and O2•−) and non-radical (1O2) processes, which was demonstrated by the quenching experiments and EPR. Besides, the composites showed better catalytic abilities than pristine biochar, which was mainly due to the increased adsorption affinity and accelerated generation of the reactive oxygen species. On the basis of the intermediates and toxicity estimation, the possible TC degradation pathways were proposed and the degradation by-products were less toxic. Above all, biochar/MoS2 materials are prospective catalysts in SO4•− based advanced oxidation processes.