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, CexMn1-xO2 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 CexMn1-xO2 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.