Ce-Fe-MI/CA composite catalyst for catalytic ozonation: Synergistic adsorption-activation via Ce/Fe sites & oxygen vacancies and application in air flotation-catalytic ozonation coupling process for pharmaceutical wastewater

In this paper, a Bimetallic MOF material Ce-Fe-MI was doped in cellulose acetate (CA) to form a composite catalyst Ce-Fe-MI/CA for catalytic ozonation degradation of tetracycline (TC) wastewater. When the mass ratio of Ce-Fe-MI to CA is 0.45:1, the removal rate of Chemical Oxygen Demand(COD) reaches 95.04% in 90 min. The Ce-Fe-MI/CA catalyst exhibits high stability, with only a 4.61% decrease in the removal of COD after four cycles of use. The active components such as •OH and 1 O 2 are produced during the Ce-Fe-MI/CA catalyzed ozonation process. Density functional theory (DFT) simulations demonstrate distinct roles of metallic sites: Ce sites dominate TC adsorption, whereas Fe sites activate catalytic ozonation. The electron transfer between Ce and Fe can effectively regulate the surface valence state and rapidly activate surface adsorbed reactants. Furthermore, the presence of oxygen vacancies in the Ce-Fe-MI/CA framework significantly enhances the catalytic performance. The air flotation-catalytic ozonation coupling process is applied to the treatment of actual pharmaceutical wastewater. The coupled system runs continuously for 480 min, and the effluent COD kept below 50 mg·L −1 .