Anti-bacterial activity of indoor-light activated photocatalysts

Nanocrystalline photocatalysts, prepared under ambient conditions using a microwave assisted synthesis, show indoor light photocatalytic activity for the degradation of Staphylococcus aureus and Escherichia coli. The zinc sulphide (ZnS) nanomaterials, prepared by a microwave assisted synthesis, are shown to be cubic blende structure with an average crystallite size of 4–6 nm. The anti-bacterial activity of these nanomaterials is investigated under irradiation from a 60 W light bulb and photocatalytic activity is revealed to be due to the defects present in the crystal structure. The ZnS shows anti-bacterial action as both a bacteriostatic and bacteriocidal (88% reduction in the amount of bacteria in 5 h) material and the methods of bacterial degradation on the ZnS is discussed. The anti-bacterial actions of these materials were also compared with commercial ZnS and Evonik-Degussa P-25. A detailed mechanism for the light absorption in the visible light region of the microwave prepared ZnS is proposed based on the luminescence spectroscopy.

Degradation rate of the bacteria in the presence of the photocatalyst.Figure optionsDownload as PowerPoint slideHighlights
► Nanocrystalline photocatalysts, prepared under ambient conditions using a microwave assisted synthesis.
► These nanomaterials show indoor light photocatalytic activity for the degradation of S. aureus and E. coli.
► A novel energy efficient method (green synthesis) to produce anti-bacterial zinc sulphide.
► The mechanism for the indoor light antibacterial photocatalysis is proposed.