Heterogeneous catalytic oxidation of tetracycline hydrochloride based on persulfate activated by Fe3O4/MC composite

[Display omitted] •A novel magnetic mesoporous carbon (Fe3O4/MC) was prepared to activate PS.•The synergistic effect between Fe3O4 and MC facilitated the PS activation.•SO4•−, •O2– and 1O2 in Fe3O4/MC + PS system mainly contributed to TC degradation.•The main degradation pathways of TC were demethylation and deamidation.•The toxicity of TC in Fe3O4/MC + PS system was greatly reduced. In this study, a novel magnetic mesoporous carbon composite (Fe3O4/MC) was prepared by manganese carbonate (MnCO3) as the template to activate persulfate (PS) for tetracycline hydrochloride (TC) degradation. The characterization results showed that Fe3O4 nanoparticles were evenly distributed on the surface of MC, and Fe3O4/MC had the large surface area of 433.88 m2∙g−1. When the initial TC concentration was 50 mg·L−1, Fe3O4/MC dosage was 0.0336 g, PS dosage was 0.0476 g and the reaction temperature was 30 °C, Fe3O4/MC + PS system could degrade 92.9% of TC within 90 min. TC degradation efficiency increased with the increase of Fe3O4/MC dosage and temperature, but decreased with the increase of TC initial concentration and pH value. The increase of PS concentration first improved TC degradation efficiency, and then was not conducive to its degradation. The quenching experiments indicated that the sulfate radical (SO4•−), superoxide radical (•O2–) and singlet oxygen (1O2) in Fe3O4/MC + PS system contributed to TC degradation. Meanwhile, the toxicity evaluation of the degradation products confirmed that the toxicity of TC in Fe3O4/MC + PS system was greatly reduced. Totally, this study systematically investigated the performance of the Fe3O4/MC + PS system for TC removal, laying a theoretical and practical foundation for treatment of potential antibiotic wastewater (ppm range) in the future.