Magnetic MgFe2O4/biochar derived from pomelo peel as a persulfate activator for levofloxacin degradation: Effects and mechanistic consideration

Biochar (BC) has been demonstrated the potential to activate persulfate (PS), but the limited catalytic efficiencies hindered their further application. Herein, an innovative magnetic MgFe2O4/BC (MMB) derived from pomelo peel was prepared for persulfate-based advanced oxidation process (PS-AOPs). Benefitting from the extraordinary properties, levofloxacin (LFX) was efficiently removed in the MMB/PS system. MMB700 exhibited the best catalytic activity, 87.87% of LFX was removed in the MMB700/PS system. In addition, it could maintain 67.90% of LFX degradation efficiency after 3 times of reuse. Quenching experiments, electron spin resonance (ESR) detection, and electrochemical test results indicated that both non-radical pathway and direct electron-transfer pathway advanced LFX degradation. LFX was oxidized by O2·- and 1O2, O2·- acted as the dominant active species. PS activation was induced by the active sites of MMB700. This work not only developed a promising magnetic biochar PS catalyst for antibiotics elimination, but also facilitated insights PS activation mechanisms.