Fe-modified ZnO for enhancing the photocatalytic removal of Levofloxacin in water via persulfate activation

Abstract In this study, iron-modified zinc oxide (Fe-ZnO) was successfully synthesized using a simple modified co-precipitation method. The material exhibited diverse surface morphologies, including particles, thin flakes, and fibers. XRD analysis confirmed the coexistence of the hexagonal wurtzite structure and an unusual ZnO crystal phase. The incorporation of iron reduced the band gap energy and enhanced the degradation efficiency of Levofloxacin (LFX) in water. An investigation into the effects of various factors on LFX degradation revealed that high removal efficiencies were achieved under neutral pH conditions, with adequate persulfate addition, and with oxygen supply. At an initial LFX concentration of 10 ppm, the photocatalytic degradation system, operating for 2 h with 500 mgFe-ZnO/L, 50 mgPS/L, unadjusted pH (∼7), UVC irradiation, and air supply at room temperature, achieved a removal efficiency of 88.01%. The introduction of dissolved oxygen promoted chain reactions, generating various reactive oxygen species (ROS) and suppressing the recombination of electron–hole pairs in the Fe-ZnO/PS/UVC system. Furthermore, radical quenching experiments identified singlet oxygen ( 1 O 2 ) as the primary ROS responsible for LFX degradation in this system. Persulfate played a crucial role in accelerating LFX degradation by facilitating ROS generation. Finally, the photocatalytic degradation mechanism and pathways of LFX were proposed.