Construction Of Double Z-scheme BiFeO₃/CuBi₂O₄/BaTiO₃ Photocatalyst For Degradation Of Norfloxacin Under Solar Light

Norfloxacin?NFX?,one of the most important classes of fluoroquinolone synthetic antibiotics,is commonly used in both human and veterinary medicine.However,NFX may interfere with the bacterial DNA replication,contaminate aquatic plants and organisms,and result in bacterial genotoxicity.Therefore,it is crucial to efficiently degrade NFX from the water body before it is discharged into the environment.In recent years,photocatalytic oxidation technology has attracted increasing attention due to its high efficiency,energy conservation,and low cost for degrading organic pollutants.However,photocatalysis technology still suffers from some shortcomings,such as limited light absorption capacity,rapid recombination of electron-holes,and poor quantum efficiency.Nowadays,single-component photocatalyst was always limited by the quick combination of photo-generated electrons and holes,which results in poor quantum efficiency and low photocatalytic activity.Recent studies have found that the photocatalytic activity of semiconductors can be improved by forming Z-scheme photocatalytic systems.Most efforts of Z-scheme photocatalysts have been devoted on binary composites.However,these binary systems were always impeded by the limited visible light response and relatively low charge separation efficiency.Thus,the fabrication of double Z-scheme ternary composites with three different band gaps which can absorb the full solar light spectrum from UV to near infrared?NIR?light is expected to be an alternative approach to effectively utilize the solar light.A novel symmetric double Z-scheme BiFeO₃/CuBi₂O₄/BaTiO₃ with the excellent photocatalytic performance was constructed using microwave hydrothermal method,and applied in the photocatalytic degradation of NFX in solution under simulated solar light irradiation.The photocatalytic activities of BiFeO₃/CuBi₂O₄/BaTiO₃,BiFeO₃,CuBi₂O₄ and BaTiO₃ nanocomposites were compared.The effects of dosage of catalysts?BiFeO₃/CuBi₂O₄/BaTiO₃?,the initial NFX concentrations,and light irradiation time on the photocatalytic activities were assessed.The mechanism on symmetric double Z-scheme BiFeO₃/CuBi₂O₄/BaTiO₃ photocatalytic degradation was also proposed.The results show that BiFeO₃/CuBi₂O₄/BaTiO₃ has higher photocatalytic activity than BiFeO₃,CuBi₂O₄ and BaTiO₃.The photocatalytic degradation extent of NFX within 60.0 min can reach 93.5%when the dosage of the BiFeO₃/CuBi₂O₄/BaTiO₃ is 1.0 g/L and the initial concentration of the NFX is 2.5mg/L.In addition,BiFeO₃/CuBi₂O₄/BaTiO₃ can be reused with excellent photocatalytic stability.The study reveals that the active species such as·OH,h⁺,and·O₂^-are generated during the photocatalytic process using BiFeO₃/CuBi₂O₄/BaTiO₃.Hence,the symmetric double Z-scheme BiFeO₃/CuBi₂O₄/BaTiO₃ photocatalytic system demonstrates great promise in treating antibiotics in water and wastewater using solar energy.