Synthesis of Y-doped ZnBi2O4 spinel oxide and its application for the photocatalytic degradation of aqueous levofloxacin under sunlight

The removal of antibiotic residues from drinking water is critical for public health to prevent long-term oxicological effects on humans and aquatic ecosystems. Spinel oxides are widely recognized as effective photocatalysts for their removal from water by photodegradation. In this work, we synthesized 1, 3, and 5% yttrium-doped ZnBi2O4 spinel oxides for the removal of levofloxacin (LVF) from water. The photocatalytic degradation of LVF under sunlight reached a maximum of 98.5% compared to 70.6% exhibited by the undoped ZnBi2O4 in 120 min for the 3% Y-doped ZnBi2O4 (YZBO-3), along with high TOC reduction. The Y3 +-doping created defects in the ZnBi2O4 lattice, creating oxygen vacancies and decreasing the band gap. The enhanced photodegradation exhibited by YZBO-3 compared to the undoped ZnBi2O4 can be attributed to improved charge separation, dopant solubility effects, and an increase in visible light absorption as suggested by XRD, Raman, and optical analyses. The results of radical trapping experiments indicate that hydroxyl (•OH) and superoxide anion (•O2−) radicals play a crucial role in the photodegradation of LVF. The reusability and stability of the photocatalyst were assessed for five cycles, and the reduction in photodegradation efficiency was quite small after five cycles of recycling and reuse.