Preparation Of The Fabrics With Air Purifying And Its Performance

At present, the pollution of indoor air has attracted increasing concern as an important environmental problem. Formaldehyde as one of the toxic substance is considered to cause cancer potentially in the world. The effective treating process of decomposing formaldehyde has been general concerned. Nano-TiO2 has plenty of excellent properties such as decomposing formaldehyde and hydrocarbons, no-toxic, high active, so it is widely applicable.Fe(Ⅲ) and La(Ⅲ) co-doped TiO2 prepared by sol-gel method was characterized in this study. The nanocatalysts have been characterized by X-ray diffraction (XRD). UV-vis diffuse reflectance spectra (DRS) and transmission electronic microscopy (TEM) analysis. Also the dispersive property of TiO2 powder was studied, the dispersion was examined by the absorbance method, laser granularity method, SEM. A number of factors that influence the dispersibility of nano-TiO2 powder,such as the pH of solution, kinds of dispersants,mechanical action and so on, were analyzed in order to obstain stable nano-TiO2 dispersion. The fabrics which have the performance of air purification were prepared by padding and coating nano-TiO2 finishing agents. The distribution of nano-particles on the fabrics was characterized by XRD, SEM and other measurements. The formaldehyde degradation of the finished fabrics was carried out in a photocatalytic reactor, and formaldehyde degradation ratio was detected by usiong acetyl acetone spectrophotometry and gas chromatography. The photocatalytic activities of fabrics, the influence of padding technics, types of nanometer powder, different co-doped proportions of Fe3+ and La3+ were also evaluated in the same reactor.It is indicated from X-ray powder diffraction data, that the co-doped TiO2 present anatase crystal form when it was heated at 500℃for 3h. the crystallites of photocatalysts are spherical particles with a crystallite size about 10-20 nm. As seen in TEM images, the crystallites were well developed, the crystalline grain was satiety. UV-vis absorption spectra of Fe3+-La3+/TiO2 showed a slightly increase in absorbancy in the visible light region. The nano-TiO2 solution used compound-dispersant present excellent dispersibility and stability under the condition of chemical and mechanical action. The average particle size in the dispersive agent was about 200nm, which can be kept stable for two weeks. According to the experimental data of degradation of formaldehyde, the process of gas-steam curing at 160℃was employed. The photocatalytic activity of Fe3+-La3+/TiO2 is superior to the self-made pure TiO2 and commodity P25. The fabric finished by Fe3+-La3+/TiO2 powder exhibited higher degradation ratio of formaldehyde above 50%after 24h irradiation in the visible light, which indicated the co-doped powder enlarged the the wavelength of maximum absorption in the visible light. There is an optimum doping ratio of Fe3+ and La3+ on TiO2. It influence the photocatalytic efficiency regardless higher or lower than that concentration. The strength of the fabric decreased according to the strength tests after finishing.