Effects of BixOyIz Self-Combination and Integration with Magnetic CoFe2O4 on the Enhanced Removal Efficiencies for Tetracycline Residues

The BixOyIz and CoFe2O4 combination enhances photocatalytic degradation of tetracyclines (TCs). Three TC antibiotics including TC, oxytetracycline (OTC), and chlortetracycline (CTC) with high concentration (50 mg L-1) were utilized as target pollutant. Bi5O7I/Bi4O5I2, with its Z-scheme, improves removal efficiency to 1.6 times that of Bi5O7I and 1.4 times that of Bi4O5I2. Ternary Bi5O7I/Bi4O5I2/CoFe2O4 (I/I/Co) composites further increase efficiency, with I/I/Co-2 achieving 1.6 times that of I/I-2. The improved performance is due to an optimized microstructure, which promotes light absorption and carrier transfer. CoFe2O4 nanoparticles on nanosheets create a double-Z band structure, enhancing redox activity. Radical trapping experiments indicated the major active species (center dot O-2(-), OH-, and h(+)) in photocatalytic process of I/I/Co-2. Based on their enhanced removal efficiencies for high-concentration TCs, proper magnetic separation capacity, and recycling performance, the practical applications of I/I/Co composites to treat real TC wastewater might be implemented.