The Preparation Of The Flexible TiO₂Photocatalytic Materials With Adsorption And Photocatalysis Functions For Air Purification

The photocatalytic technology of air purification using nanoscale TiO2asphotocatalyst has been a hot spot in the world. Contrast with other conventionaltechniques, nanostructured photocatalytic technology has more advantages such ashigher treatment efficiency, lower energy consumed, more easily controlled, nosecondary pollution etc, so show the wide application prospect in the field of airpurification.The purpose of this thesis is to remove the formaldehyde in indoor air byphotocatalytic oxidation technology. The contents of the research include designingand manufacturing the photocatalytic reactor, the preparation and evaluation ofphotocatalytic materials, improving the efficiency of photocatalytic materials and theanalysis of the influence of different factors on the efficiency of photocatalyticmaterials. We prepared the flexible TiO2photocatalytic materials with adsorption andphotocatalysis functions. The prepared photocatalytic materials were characterized byscanning electronic microscopy (SEM), transmission electron microscope (TEM),X-ray diffraction (XRD), UV-VIS spectrometer (UV-VIS)and etc. for their structureand properties. The research mainly includes the following aspects:(1) TiO2/SiO2/C films were prepared by suspension system and dip coatingmethod on paper, which had adsorption-photocatalytic functions. Suspensionconcentration, coating cycle, dipping time, composition of TiO2/SiO2/C were studiedin order to get good morphology and make the best photocatalysis, try to analysis thebonding performance and the photocatalytic properties of the film. The results showedthat, when the concentration of the suspension was5wt%, coating layer was3, the dipping time was5s, couid obtain better photocatalytic film morphology. Thesuspension was composed of by TiO2, SiO2and C when the quality ratio was70:20:10,could obtain the best bonding and photocatalytic properties which had the highestphotocatalytic efficiency of26.7%when the initial concentration offormaldehyde was2.23mg/m3.(2) At the basis of above study, TiO2/SiO2fibrous membranes were prepared bysol-gel and electrospinning methods, the fibrous membranes combined with activatedcarbon fiber cloth which were self-supporting were adsorption-photocatalyticmaterials.The morphology of samples could be controlled by adjusting the voltage,the injection speed and the humidity. After the heating treatment, the diameters oftheTiO2/SiO2fibrous membranes decreased, but the surface of the fibers retainssmooth and uniform. At the same time, the TiO2/SiO2fibrous membranes present therelatively high tensile strength (2.09MPa), which exhibited no cracks after bendingand recovering process. By comparing different composed of TiO2/SiO2fibermembranes found that when the ratio was2:1, can obtain the best photocatalyticproperties which has the highest photocatalytic efficiency of100%when the initialconcentration of methylene blue was10mg/L after three cycles in the waterpurification illustration. The photocatalytic efficiency was54.4%when the initialconcentration of formaldehyde was2.31mg/L after tow hours in the air purificationillustration.The efficiency was improved to59.1%when combined with activatedcarbon fiber. The adsorption-photocatalytic materials will be widely used.