New types of visiblelightdriven photocatalysts with high activity for bacterial inactivation are needed to address the problems caused by outbreak of harmful microorganisms. In this study, cadmium indium sulfide (CdIn₂S₄) microsphere, which can be synthesized continuously by a facile ultrasonic spray pyrolysis method, was used as an efficient photocatalyst in inactivation of Escherichia coli K12 under visible light (VL) irradiation for the first time. The asprepared CdIn₂S₄ showed a microspherical morphology with diameter of 0.5–1.0 μm. It had an energy band gap of 2.02 eV and BET surface area of 34.8 m²/g. It was found that bacterial cells could also be effectively inactivated inside a partition system without the direct contact with the photocatalyst, which was attributed to the diffusible photongenerated hydrogen peroxide (H₂O₂) rather than hydroxyl radicals (•OH). Large amounts of H₂O₂ were produced from both conduction and valance bands with the involvement of superoxide (•O2−). The used CdIn₂S₄ could be easily recycled by the partition system without loss of activity. The destruction process of bacterial cells was from the cell wall to the intracellular components as confirmed by TEM study. In addition, the •O2−and •OH radicals were also detected in the CdIn₂S₄-VL system by ESR spintrap with DMPO trapping technology. Copyright © 2012 Elsevier B.V.
CitationWang, W., Ng, T. W., Ho, W. K., Huang, J., Liang, S., An, T., et al. (2013). CdIn₂S₄ microsphere as an efficient visible-light-driven photocatalyst for bacterial inactivation: Synthesis, characterizations and photocatalytic inactivation mechanisms. Applied Catalysis B: Environmental, 129, 482–490.
- Photocatalytic inactivation
- Ultrasonic spray pyrolysis
- Partition system
- Hydrogen peroxide