Degradation of tetracycline by activated peroxodisulfate using CuFe2O4-loaded biochar

CuFe2O4 is often loaded onto biochar (BC) to prepare activated peroxodisulfate (PDS) catalysts for the removal of persistent organic pollutants from water. However, the activation mechanism remains unclear. Therefore, in this study, a BC-loaded CuFe2O4 (CuFe2O4@BC) system that activates PDS was constructed and used to degrade the antibiotic tetracycline (TC). The synthesized materials were fully characterized, and the optimal reaction conditions of the system were determined to be a CuFe2O4@BC dosage and PDS concentration of 0.1 mg/L and 10 mM, respectively, under acidic conditions, achieving a TC removal of 30 mg/L. Under these conditions, the removal efficiency reaches 96.0 %. The synergistic effect of CuFe2O4 and BC greatly improves catalytic performance and avoids the agglomeration of the metallic nanoparticles. The PDS-activation mechanism was studied through electron paramagnetic resonance and quenching experiments, revealing that TC is degraded under the combined effects of sulfate radicals (SO4•−), hydroxyl radicals (•OH), and singlet oxygen (1O2). Two plausible degradation pathways of TC are proposed. Overall, this study provides a deeper understanding of metal-modified biochar activated PDS and provides a new strategy for the degradation of TC in this catalytic system.