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

The Bi_xO_yI_z 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 (•O₂⁻, 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.