Enhanced Catalytic Ozonation by Mn-Ce Oxide-Loaded Al₂O₃ Catalyst for Ciprofloxacin Degradation

Catalytic ozonation is an effective and promising advanced oxidation technology for organic pollutant removal. Herein, CexMn_1-O₂ metal oxides loaded on Al₂O₃ catalysts (Mn-Ce/Al₂O₃) were synthesized for catalytic ozonation of the wastewater containing ciprofloxacin. The morphology, crystal structure, and specific surface area of the prepared catalyst were characterized. The characteristics of the Mn-Ce/Al₂O₃ catalyst revealed that the loaded MnO₂ could interfere with the formed CeO₂ crystals and then produced complex CexMn_1-O₂ oxides. Compared with an ozone-alone system (47.4%), the ciprofloxacin degradation efficiency in the Mn-Ce/Al₂O₃ catalytic ozonation system elevated to 85.1% within 60 min. The ciprofloxacin degradation kinetic rate over the Mn-Ce/Al₂O₃ catalyst is 3.0 times that of the ozone-alone system. The synergetic corporation of redox pairs between Mn(III)/Mn(IV) and Ce(III)/Ce(IV) in the Mn-Ce/Al₂O₃ catalyst could accelerate ozone decomposition to generate active oxygen species and further significantly improve the mineralization efficiency of ciprofloxacin. The work demonstrates the great potential of developing dual-site ozone catalysts for advanced treatment of wastewater.