Photocatalytic antibacterial performance of Sn 4+-doped TiO 2 thin films on glass substrate (original) (raw)
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Beilstein Journal of Nanotechnology, 2013
Pure anatase, nanosized and Sn 4+ ion doped titanium dioxide (TiO 2 ) particulates (TiO 2 -Sn 4+ ) were synthesized by hydrothermal process. TiO 2 -Sn 4+ was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn 4+ doping to TiO 2 against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO 2 -Sn 4+ in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO 2 -Sn 4+ is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO 2 -Sn 4+ from 10 to 50% in the coating solution increased antibacterial effect.
Titanium dioxide is a photocatalyst with well-known ability to oxidise a wide range of organic contaminants as well as to destroy microbial cells. In the present work TiO 2 nanoparticles with high specific surface area (150 m 2 /g) were used to prepare nanostructured films. The TiO 2 nanoparticle-based film in combination with UV-A illumination with intensity (22 W/m 2 ) comparable to that of the sunlight in the UV-A region was used to demonstrate light-induced antibacterial effects. Fast and effective inactivation of Escherichia coli cells on the prepared thin films was observed. Visualization of bacterial cells under scanning electron microscopy (SEM) showed enlargement of the cells, distortion of cellular membrane and possible leakage of cytoplasm after 10 min of exposure to photoactivated TiO 2 . According to the plate counts there were no viable cells as early as after 20 min of exposure to UV-A activated TiO 2 . In parallel to effects on bacterial cell viability and morphology, changes in saturated and unsaturated fatty acids -important components of bacterial cell membrane-were studied. Fast decomposition of saturated fatty acids and changes in chemical structure of unsaturated fatty acids were detected. Thus, we suggest that peroxidation and decomposition of membrane fatty acids could be one of the factors contributing to the morphological changes of bacteria observed under SEM, and ultimately, cell death.
Journal of Alloys and Compounds, 2015
Simple sol-gel method has been exploited to deposit Sn-doped TiO 2 thin films on glass substrates. The resultant coatings were characterized by X-ray diffraction (XRD), UV-visible techniques (UV-Vis), Fourier transform infrared spectroscopy (FTIR), and photoluminescence analysis (PL). The XRD pattern reveals an increase in crystallite size of the prepared samples with the increasing doping concentration. A decrease in doping concentrating resulted in the decrease in bandgap values. The different chemical bonds on these films were identified from their FTIR spectra. The photoluminescence analysis shows an increase in the emission peak intensity with increasing dopant concentration, and this can be attributed to the effect created due to surface states. The prepared samples were tested as antibacterial agent toward both Gram-positive and Gram-negative bacteria like S.aureus (Staphylococcus aureus) and E.coli (Escherichia coli), respectively. The size of the inhibition zones indicates that the sample shows maximum inhibitory property toward E.coli when compared to S.aureus.
Journal of Materials Chemistry, 2009
Sulfur-doped titania thin films were prepared by atmospheric pressure chemical vapour deposition (APCVD) for the first time using titanium tetrachloride, ethyl acetate and carbon disulfide. The films were compared to two industrial self-cleaning products: ActivÔ and BIOCLEANÔ, and shown to be superior in both photocatalysis and photo-induced superhydrophilicity, two preferential properties of effective self-cleaning coatings. X-Ray diffraction showed the films have the anatase TiO 2 structure. XPS and EDX analysis shows changes in S : Ti ratio with preparative conditions indicating that sulfur has indeed been incorporated into the lattice. S-Doped TiO 2 films were found to be effective agents for killing the bacterium Escherichia coli using light sources commonly found in UK hospitals.
World Journal of Microbiology and Biotechnology, 2009
This work focuses on the photocatalytic performances and antibacterial activity of nitrogen doped TiO 2 nanosystems with three and five layers obtained by a sol-gel route, followed by thermal treatment in oxygen or ammonia atmosphere at temperatures between 400 and 1000°C. Subsequently, the antibacterial activity of the obtained nanosystems on the Escherichia coli cells are determined and discussed. The obtained results show a significant dependence of the functional performances on the system's composition. In particular, the antimicrobial activity of nitrogen-doped TiO 2 films is correlated with the temperature of thermal treatment and illumination time with visible artificial light.
Journal of Photochemistry and Photobiology A: Chemistry, 2002
The present study investigated bactericidal and photocatalytic activities of transparent anatase TiO 2 thin films on soda-lime glass prepared by using reverse micelle and sol-gel methods. Both films exhibited significant bactericidal activity towards three strains of Escherichia coli, namely DH5␣, JM109 and XL1 Blue MRF'. The TiO 2 films were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray diffraction (XRD), and UV-Vis spectrometry. Results of photocatalytic activity measurements suggest that the TiO 2 film prepared by the reverse micelle method is a better photocatalyst than that prepared by sol-gel method in gaseous phase oxidation but their activities in aqueous phase are about the same.
Songklanakarin Journal of Science and Technology
Titanium dioxide photocatalysts were synthesized by sol-gel process, by varying the reaction conditions, acids, water content, and trivalent (Al, B) dopants. The characterizations of products were determined by XRD, SEM, BET, and UV-vis spectroscopy. The samples were mainly amorphous with a small amount of anatase, rutile, or a mixture of anatase and rutile, with a crystallite sizes of about 5-10 nm. The antibacterial activity of the synthesized TiO2 samples were investigated qualitatively and semi-quantitatively. Five types of bacteria, Escherichia coli ATCC25922, Psudomonas aeruginosa ATCC27853,Bacillus subtilis BGA, Staphylococcus aureus ATCC25923, and methicillin-resistant S. aureus (MRSA) DMST 2054, were used for the inactivation experiment employing the agar dilution method. All the synthesized samples showed inactivation activity with varying degree of efficiency. Two of them showed a much higher activity than Degussa P25.
Photobactericidal effects of TiO2 thin films at low temperatures—A preliminary study
Journal of Photochemistry and Photobiology A: Chemistry, 2010
The efficacy of TiO 2 photocatalysis for the destruction of pathogenic bacteria has been demonstrated by a number of groups over the past two decades. Pathogenic bacteria represent a significant hazard for the food and drink industry. Current practices in this industry dictate that rigorous sanitizing regimes must be regularly implemented resulting in lost production time. The incorporation of a TiO 2 antibacterial surface coating in this setting would be highly desirable. In this paper we report a preliminary study of the efficacy of a TiO 2 coating, doped with the lanthanide, neodymium, at low temperature conditions such as those utilised in the food and drink sector. The rapid destruction of Staphylococcus aureus, a common foodborne pathogen, was observed using TiO 2 films coated to glass and steel substrates.
Coatings, 2014
In damp environments, indoor building materials are among the main proliferation substrates for microorganisms. Photocatalytic coatings, including nanoparticles of TiO 2 , could be a way to prevent microbial proliferation or, at least, to significantly reduce the amount of microorganisms that grow on indoor building materials. Previous works involving TiO 2 have already shown the inactivation of bacteria by the photocatalysis process. This paper studies the inactivation of Escherichia coli bacteria by photocatalysis involving TiO 2 nanoparticles alone or in transparent coatings (varnishes) and investigates different parameters that significantly influence the antibacterial activity. The antibacterial activity of TiO 2 was evaluated through two types of experiments under UV irradiation: (I) in slurry with physiological water (stirred suspension); and (II) in a drop deposited on a glass plate. The results confirmed the difference in antibacterial activity between simple drop-deposited inoculum and inoculum spread under a plastic film, which increased the probability of contact between TiO 2 and bacteria (forced contact). In addition, the major effect of the nature of the suspension on the photocatalytic disinfection ability was highlighted. Experiments were also carried out at the surface of transparent coatings formulated using nanoparticles of TiO 2 . The results showed significant antibacterial activities after 2 h and 4 h and suggested that improving the formulation would increase efficiency.
2014
In this research, undoped and doped (Fe, Ce, and Ag) antibacterial coatings of nanostructured TiO2 films were prepared by a sol-gel dip coating method. Doped and undoped TiO2 films were excited with ultraviolet (UV) radiation to improve their photo catalytic activity. The antibacterial activity against Staphylococcus Aureus bacteria was studied using an antibacterial–drop test and colony count method. The Fe doped TiO2 films exhibited higher antibacterial activity than other samples. The percent of bacteria killing or killed (PBK) on bare glass substrate, undoped, Ce, Ag, and Fe doped TiO2 thin films (after UV illumination) were 23.8, 50.3, 57.8, and 70.1%, respectively. Uv-Visible Spectrophotometry, Photoluminescence (PL), X-ray Diffraction (XRD), and Atomic Force Microscopy (AFM) were carried out to study the relation between optical, luminescence, structural, and surface morphological characteristics of the samples with their antibacterial activities. Several parameters such as t...