Synergistic radical-mediated algal inactivation via FeMoS2/ZnO-persulfate visible-light photocatalysis

Abstract

FeMoS₂/ZnO heterojunction photocatalysts were successfully prepared by hydrothermal synthesis. Scanning electron microscopy (SEM) study revealed that a 3-dimensional porous structure was formed by the uniform distribution of ZnO nanoparticles on the surface of FeMoS₂ nanosheets; the distinctive diffraction peaks of ZnO and FeMoS₂ were concurrently visible in X-ray diffraction (XRD) patterns, verifying that there were no notable alterations to the two crystal structures during the composite's creation procedure. The successful doping of Fe was validated by an examination using XPS. As demonstrated by UV–Vis DRS, the composite material's light absorption edge was red-shifted from 650 nm to 720 nm in pure FeMoS₂, and the band gap width decreased from 1.85 eV to 1.72 eV. These findings suggested that the addition of ZnO had greatly increased sensitivity of the material to the visible light spectrum. The variations in malondialdehyde (MDA), superoxide dismutase (SOD), zeta potential, phycobiliprotein and SEM physiological indexes during the catalytic process were detected, and the cell shape of Chlorella vulgaris was found to be significantly harmed by the FeMoS₂/ZnO/PDS/Vis system. Analysis using free radical trapping and EPR revealed that the primary active species in this system's algal inactivation mechanism were hydroxyl radicals (HO•). In light of these findings, a possible response mechanism for the FeMoS₂/ZnO/PDS/Vis inactivation of algae was put forth.