| Nano-titanium dioxide (TiO2) in the photocatalytic process, due to its low captured efficiency of photoelectron and other factors, is limited in the field of application of special coatings. β-cyclodextrin(β-CD) is an organic adsorbent with strong inclusion. Therefore, it is considered that β-CD is polymerized and cladding on the surface of nano-titania to prepare nano-TiO2/CDP composite-based special coatings of adsorption-catalysis linkage.In this paper, the preparation, characterization, primary and secondary photocatalytic properties of nano TiO2/CDP composite coatings were studied.Firstly, nano TiO2/CDP composites with uniform particle size, proper viscosity and good suspension stability were prepared by improving the pretreatment of nano-TiO2, the ratio of P-CD and nano-TiO2 and the ratio of β-CD and epichlorohydrin(EPI). The composites were characterized by IR, UV, SEM and TG. The results showed that β-CD was successfully cladding on the surface of nanosized Ti02. The composite had strong ultraviolet absorption and good thermal stability.Secondly, the influence of pH and the amount of sodium silicate on the particle size,viscosity and suspension stability of the composite coating liquid was analyzed by experiments. The optimum dosage of sodium silicate is 0.5% and the optimum pH is 7, the particle size of the coating is uniform, the viscosity is suitable and the suspension stability is the best.Finally, the photocatalytic performance of nano TiO2/CDP composite coatings was studied. The results showed that: (1) the photocatalytic activity of composite coatings was stronger than that of nano-TiO2; (2) With the increase of initial formaldehyde concentration,the initial adsorption rate of formaldehyde was decreased, as well as final catalytic degradation rate; (3) Nano TiO2/CDP composite coating prepared by pretreatment of nano TiO2 has higher initial adsorption rate of formaldehyde gas and higher final degradation rate of formaldehyde. (4) With the increase of β-CD, the initial adsorption capacity of nano-TiO2/CDP composite coatings increased, but its catalytic ability was weakened. When the mass ratio of β-CD to nano-TiO2 was 1:10, the nanometer TiO2/CDP composite coating had the best catalytic activity and the second-use effect was the best. (5) With the increase of the amount of EPI, the initial adsorption effect of nanometer TiO2/CDP composite coating is getting worse and the catalytic linkage is also weakened. When the molar ratio ofβ-CD and EPI was 1:15, the catalytic activity of nano-TiO2/CDP composite was the best,and the second-use effect was the best and the catalytic efficiency was the best. |
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