Research On Antibacterial Properties Of Doped Nano-TiO₂ Powder

Research progress on doped modification and antibacterial application of nano-TiO₂ photocatalysis were intensively summarized firstly, and also the preparation methods, photocatalytic and antibacterial mechanisms of nano- TiO₂ were introduced in this article. According to the recent research on the field of antibacterial property of TiO₂, the background, meaning and way of our study are also pointed out.Study on the photocatalytic antibacterial property of doped nano-TiO₂ was focused in the experiment part. First of all, the transparent, stable TiO₂ sol was prepared by Sol-Gel method with Ti(OC₄H₉)₄ as precursor at ambient temperature. Many different factors which have impacts on the gel time and the physical parameter of powder were studied, and also the best matching and reacting condition were determined, after that, the doping modified nano-TiO₂ were prepared successfully. The microstructure and antibacterial property of different types of TiO₂ were analyzed by means of TEM, XRD, FT-IR, TG-DSC, and UV-VIS-NIR and so on, and also the antibacterial property was tested by disinfection experiment. For the Ag-doped TiO₂ nano-material, we studied the effects of preparation condition and experiment condition on the antibacterial property by qualitative and quantitative methods. For the La-doped TiO₂ nano-material, using methyl orange as degradation object, at first, under the natural sunlight illumination, the effects of preparation condition and experiment condition on the photocatalytic property of nano-TiO₂ were investigated, then the antibacterial property of La-doped TiO₂ was also studied, the antibacterial property of Ag and La co-doped nano-TiO₂ was researched at last.The results showed that the optimum conditions for preparing TiO₂ sol were obtained as follows: at ambient temperature, HAc as stabilizer, HNO₃ as catalyst, the molar ratio among Ti(OC₄H₉)₄, C₂H₅OH and H₂O is 1:12:9, sol pH value is 2-4, B solution addition rate is 1-2 s/drop, agitation rate is moderate;Ag doping promotes the formation of anatase but has little effect on the phase transformation from antanse to rutile, La doping inhibits the phase transformation and the size of grain gets smaller gradually, and Ag and La ions co-doping has a synergic effect on grain growth and TiO₂ phase transformation from anatase to rutile;When the Ag⁺ doped concentrationis 2%, heating treatment is 400⁵00°C, A:R=3:1, and UV illumination time is 60 90min, Ag-doped TiO2 have the best antibacterial property whose largest diameter of inhibition zone can reach 17mm;The antibacterial property of Ag and La ions co-doped TiC>2 is much better than only Ag ion doped T1O2, with the increasing of La doped concentration, the diameter of inhibition zone gets bigger remarkably which can reach 27mm;Under the light source of sunlight, the bactericidal ability of Ag or La doped TiO2 is much stronger than pure TiO2, the largest bactericidal rate reaches 99%.