Study On Visible Light Photocatalytic Ability Of TiO₂ Modified By Derivatives Of PVC

The TiO₂/PVC nanocomposites were prepared by impregnating TiO₂ into the solution of polyvinyl chloride. The TiO₂/CP-PVC nanocomposites with the surface modified by the conjugated polymer were prepared by the dehydrochlorination of polyvinyl chloride when the TiO₂/PVC nanocomposites were heated at 150℃for 2h, and characterized by transmission electron microscopy （TEM）, X-ray diffraction（XRD）, X–ray photoelectron spectroscopy （XPS）, UV–visible diffuse reflectance spectroscopy （UV–Vis DRS）, Fourier-transform infrared spectroscopy （FTIR） and Raman spectroscopy. The results show that the conjugated polymer derived from PVC exists on the surface of the as-prepared nanocomposites, and the modification of the conjugated polymer can obviously improve their absorbance in the range of visible light, but hardly change their mean sizes and crystallinity.The visible light photocatalytic activities and stability of the TiO₂/CP-PVC nanocomposites were studied by evaluating the degradation of Rodamine B （RhB） catalyzed by the nanocomposites under visible light irradiation. The results show that the TiO₂/CP-PVC nanocomposites possess the excellent visible light photocatalytic activities and stability. The effects of the preparation conditions （such as mass ratio of PVC and TiO₂, the heat-treatment temperature, I2 doping and so on） and photocatalytic degradation conditions （such as the initial concentration of RhB, catalyst dosage, pH of RhB solution and so on） on the visible light photocatalytic activities were investigated. The results show that: （1） TiO₂/CP-PVC nanocomposites possess the optimal photocatalytic activity when the mass ratio of PVC and TiO₂ is 1:100 and the heat-treatment temperature is 150℃; （2） I2 doping can greatly increase the photocatalytic abllity of TiO₂/CP-PVC; （3） the initial concentration of RhB, catalyst dosage, pH of RhB solution significantly affect the photocatalytic abllity of TiO₂/CP-PVC nanocomposites.The PVC film containing TiO₂ nanoparticles was prepared by the solution casting method. The composite film CP-PVC/TiO₂ was obtained by the heat-treatment of PVC/TiO₂ film at the higher temperares such as 150℃, and characterized by SEM, XRD, UV-vis DRS. The visible light photocatalytic activity and stability of film were studied with Rodamine B （RhB） as the model contaminant. The results show that the TiO₂ nanoparticles were homogeneously dispersed into the polymer matrix and their size and crystallinity do not change; the as-prepared composite film possesses the improved adsorbance in the range of the visible light and excellent visible light photocatalytic activity and stability.