title: ZnO/TiO2composites for photocatalytic inactivation of Escherichia coli.
abstract: ZnO/TiO2composite was synthesized from zinc nitrate and anatase TiO2by using the incipient wet impregnation method followed by calcination at 350°C for 3h. These samples were characterized through several characterization techniques. XRD peaks confirms the presence of single anatase phase of titania in the 3 and 6wt% ZnO/TiO2composite, whereas in all other composites both anatase titania and zinc oxide phases were found. UV-visible (diffuse) reflectance spectra show titania and ZnO absorbs in the ultraviolet (UV) region whereas ZnO/TiO2absorbs both UV and visible light. The shift in absorbance facilitates ZnO/TiO2composites to exhibit photocatalytic activity under UV-visible light irradiation. FE-SEM and TEM analysis reveals that the particle size of ZnO is around 0.2μm and its size significantly reduced to 25nm when it is deposited on TiO2support. The E. coli inactivation study shows that ZnO/TiO2composites exhibit high inactivation compared to ZnO and titania under UV alone and the combination of both UV-visible. With the increasing loading concentration of ZnO, the photocatalytic inactivation potential of ZnO/TiO2composites also increases. The E. coli inactivation of ZnO/TiO2is explained based on the photocatalytically generated ROS, ZnO dissolution and charge carrier separation due to hybrid structures.
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110 001, India; CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, India.
authors.forename: Diptipriya
authors.initials: D
authors.lastname: Sethi
authors.affiliation: CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, India. Electronic address: rsakthivel@immt.res.in.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Sakthivel
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D002384:Catalysis; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D017382:Reactive Oxygen Species / Q000378:metabolism; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays; D015034:Zinc Oxide / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D017382:Reactive Oxygen Species; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide
keywords: Hybrid structure; Photocatalytic effect; Reactive oxygen species; ZnO/TiO(2) composites