Ce-Fe bimetallic zeolite-imidazolate framework catalyzed ozonation for enhanced tetracycline degradation: synergistic electron transfer and multi-radical reaction pathways

In this paper, the bimetallic zeolite imidazolate framework Ce-Fe-MI as a high-performance catalyst for ozonation-based degradation of tetracycline (TC) was investigated. During the catalytic process, electron transfer occurred between the two metal ions on the catalyst, and the mixed-valence state induced charge imbalance and unsaturated bonds, thereby forming catalytically active sites. Through comprehensive characterization and experimental evaluation, the Ce-Fe-MI catalytic ozonation process significantly enhanced the removal efficiency of COD and TOC, achieving a mineralization rate of 50% higher than ozonation alone. EPR identified the presence of uperoxide radicals (•O 2 - ) and singlet oxygen ( 1 O 2 ) as the main active species; however, quantitative analysis revealed hydroxyl radicals (•OH) was the main contributor to the degradation of pollutants, indicating the involvement of all three reactive oxygen species (ROS) in the catalytic ozonation reaction process. Density functional theory (DFT) calculations further demonstrated that the synergistic Ce-Fe interactions promoted electron transfer and facilitated ozone activation, leading to enhanced generation of reactive oxygen species. These findings emphasize the potential of Ce-Fe-MI catalyzed O 3 as an efficient and advanced oxidation process for antibiotic wastewater treatment.