Boosted antibiotic degradation using magnetite nanoparticles doped ultrafine activated charcoal powder to activate H₂O₂: Insights into mechanisms and competitive kinetics

The treatment of antibiotic wastewater often faces the challenge of simultaneously and effectively degrading multiple components under complex conditions. To address this challenge, magnetite nanoparticles doped ultrafine activated charcoal powder (MNPs/UACP), which effectively catalyzed the decomposition of H₂O₂ into •OH and HO₂•, was prepared using chemical co-precipitation. Under optimum conditions (i.e., tetracycline (TC) concentration = 100 ppm, pH = 3, H₂O₂ concentration = 4.9 mM, catalyst dosage = 0.5 g/L), the 50% MNPs/UACP-H₂O₂ system achieved 97.5% TC removal within 180 min, driven by the synergistic action between adsorption and catalytic oxidation. The stability of 50% MNPs/UACP in recycling was evaluated through repeated reaction cycles, demonstrating that the TC removal efficiency remained at 91.0% even after five cycles. The competition among TC, oxytetracycline (OTC), and chloramphenicol (CAP) in the MNPs/UACP-H₂O₂ system was closely related to the catalytic oxidation performance, and increasing the proportion of MNPs in MNPs/UACP to above 50% effectively reduced the competition, optimizing degradation efficiency. This study is among the first to provide a comprehensive understanding of adsorption-catalytic oxidation coupled system, offering new insights for broad environmental applications.