Preparation And Properties Of Titanium Dioxide Photocatalytic Antibacterial Film

Semiconductor photocatalysis technology has broad application prospects in the degradation of organic pollutants.Among them,the TiO₂film has the advantages of being cheap and easy to obtain,high optical and chemical stability,being non-toxic and harm Less,and being recyclable and reusable.The TiO₂film prepared by the conventional sol-gel method is easy to form cracks when dried,and has low photocatalytic activity and antibacterial ability.In this paper,four-factor four-level orthogonal experiments are designed,and the study revealed the influence of single factors such as TBOT,H₂O and PVP content,calcination temperature,and silver/zinc doping on the microstructure and properties of TiO₂films.The optimal ratio and preparation process of TiO₂film were obtained,and the research results are as follows:First,through 16 sets of orthogonal experiments with four factors and four levels,the ratio and preparation process of TiO₂film prepared by the sol-gel method were preliminarily determined.A TiO₂film with no cracks,no holes,good light permeability and excellent photocatalytic activity was prepared.The single factor effect experiment found that the TiO₂film calcined at 450°C has the best performance.Too low a calcination temperature will result in incomplete crystallization of TiO₂,and too high a temperature will cause the TiO₂grain size to be too large and the photocatalytic performance to decrease.The TiO₂film prepared by adding 5m L TBOT to 100m L absolute ethanol is colorless and transparent,and has good photocatalytic activity.The content of H₂O in the sol has a significant effect on the surface micromorphology,photocatalytic performance and visible light transmittance of the TiO₂film.With the increase of PVP addition,the TiO₂crystal grains are gradually refined,but the surface roughness increases.When the addition is 6%,TiO₂film with the best performance is obtained.On the basis of the preliminary ratio and preparation process obtained by orthogonal experiment,combined with the influence law of single factor,the best preparation process of TiO₂film is obtained.It was found that the sol prepared by using 100m L of absolute ethanol as the solvent,adding 5m L of TBOT,7m L of H₂O,and 6%PVP（6%of the mass of TBOT）with dipping,pulling and calcining at 450°C for 1 hour can make the TiO₂film which has the best photocatalytic and light transmittance properties.After Ag doping,brookite phase appears in TiO₂,and the roughness of the film is reduced.Ag exists in the TiO₂lattice in a zero valence state.The TiO₂film doped with 1%Ag has the best photocatalytic performance and light transmission performance.Its antibacterial rate reached 99.3%,much higher than that of undoped TiO₂film（<70%）.As the calcination temperature increases,the roughness of the film increases,and the Ag in the TiO₂lattice is partially oxidized.When the calcination temperature reaches 550°C,the TiO₂film doped with1%Ag is completely anatase type and the grain size increases significantly.After doping with Zn,the TiO₂film is still in the anatase phase.As the doping amount increases,the TiO₂grain size gradually increases,the film roughness gradually decreases,and the light transmittance gradually rises.Zn exists in the TiO₂lattice in the form of Zn²⁺,and the number of hydroxyl groups on the surface of the film increases.The film doped with 5%Zn has the best photocatalytic activity and the best antibacterial performance,with an antibacterial rate of97.9%.As the calcination temperature increases,the average roughness of the film gradually decreases.When the calcination temperature reaches 550°C,the TiO₂grain size increases significantly.