Mechanistic investigation of visible light driven photocatalytic inactivation of E. coli by Ag-AgCl/ZnFe2O4

Visible light-activated 1-D core-shell paramagnetic Fe-Ag@AgCl as an innovative method for photocatalytic inactivation of E. coli

Innovative paramagnetic one-dimensional (1-D) core-shell Fe-Ag@AgCl visible light-driven photocatalysts are synthesized through a template-assisted electrodeposition method trailed by FeCl₃ in-situ oxidation. The metallic nature of Fe-Ag@AgCl is confirmed through scanning electron microscopy (SEM) and crystal nature through X-ray diffraction (XRD). The controllable diameter of Fe-Ag is obtained through the selection of hollow size of the polycarbonate (PC) template. Electron impedance spectroscopy (EIS) confirms through the introduction of Fe to the Ag core that has prolonged the recombination of electron and hole. Escherichia coli (E. coli) are employed as the target bacteria to evaluate the photocatalytic disinfection performances. A total of 1.30 mg of Fe-Ag@AgCl is proved to be able to completely inactivate 10⁷ CFU (colony forming units)/mL after 120 min of visible light irradiation. The transition electron microscopy (TEM) confirms the stability of the material after the photo reaction. As Fe-Ag@AgCl possesses magnetic properties, the material is recovered through the application of an external magnetic field. SEM images and results of 3D emission extraction matrix (EEM) depict that the bacteria cell death is caused by membrane permeability changes caused by the reduction of membrane associated proteins.