Ce-modified NH2-MIL-88B enhances catalytic ozonation for effective antibiotic degradation

Abstract

A Ce-doped NH₂-MIL-88B(Fe) composite (Ce-NM8B) was synthesized via a hydrothermal method and used to catalyze ozone oxidation to degrade levofloxacin (LEF) in water. Moreover, comprehensive characterization of Ce-NM8B, including crystal structure, surface morphology, and electrochemical properties, was performed using XRD, SEM, BET, XPS, FT-IR, and ICP techniques. As a result, the Ce-NM8B/O₃ system achieved an 84.2 % degradation of 10 mg/L LEF within 40 min under optimal conditions (0.20 g/L catalyst dosage, 0.20 L/min ozone flow, pH 7). Furthermore, EPR and radical quenching experiments confirmed the generation of ·OH, O₂·^-, and ¹O₂ species, in addition to direct ozone oxidation and catalytic adsorption. Additionally, HPLC-MS analysis identified key degradation pathways, including piperazine, quinolone, and morpholine ring cleavage, alongside decarboxylation, defluorination, and demethylation. In terms of toxicity, evaluation using T.E.S.T. revealed that intermediate products exhibited reduced toxicity. Moreover, Ce-NM8B demonstrated stable performance over three cycles. Finally, the system's applicability and practical potential were confirmed through the degradation of several antibiotics and testing in natural water substrates.