Study On Photocatalytic Activity Of Derivation Of Polyisoprene Modified Nanoparticles Titanium Dioxide

A series of TiO2/ polyisoprene nanocomposites were prepared by the solution immersion method. The brominated polyisoprene was obtained by brominating polyisoprene on the surface of TiO2/polyisoprene nanocomposites in the bromine solution. The TiO2/conjugated polyene (TCP) nanocomposites were successfully synthesized by the dehydrobromination of brominated polyisoprene when TiO2/brominated polyisoprene nanocomposites were heated. The above nanocomposites were characterized by transmission electron microscopy (TEM), Fourier-transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy spectrum (XPS), X-ray diffraction (XRD), EDS, Raman spectroscopy, SSA and UV-vis diffuse reflectance (UV-vis DRS). The results showed that a layer of conjugated polymer was successfully absorbed on the surface of TiO2 nanoparticles. The modification of the conjugated polymer does not alter the size, crystalline structure and the dispersivity of the TiO2 nanoparticles while greatly improves the absorbancy of the nanocomposites in the whole range of visible light.The visible light photocatalytic activity and stability of TCP nanocomposites were studied by the degradation of methylic orange as the model contaminant under visible light obtained from the two fluorescent lamps with a 400 nm cutoff filter to ensure the desired irradiation light. Results show that the TCP nanocomposites have outstanding visible light photocatalytic activities and good photocatalytic stability. The effects of chemical composition of the nanocomposites, dehydrobromination temperature and time dehydrobromination environments, photocatalytic reaction temperature, pH of MO solution, scavenger of electrons or holes on the visible light photocatalytic activity of TCP nanocomposites were investigated. It can be found that at the TCP nanocomposites have the best photocatalytic activity when the molar ratio of polyisoprene and TiO2 was 1:10, the dehydrobromination temperature and time were 100℃and 4h, respectively. The photodegradation rate of MO increases with the increment of photodegradation temperature, increases and then decreases with the increment of pH of the initial MO solution and the highest is at pH=4.8. The photodegradation rate of MO in the presence of LCP nanocomposites is hardly affected by isobutyl alcohol (electron scanvenger) while significantly depressed by ethylene diamine tetraacetic acid (EDTA, hole scavenger), indicating that the photogenerated holes may be the main active species in MO degradation photocatalyzed by TCP nanocomposites. The mechanism of MO photodegradation of MO catalyzed by TCP was also discussed.Iodine is the typical doping agent of conjugated polymers, which can obviously improve electronic conductivity of the conjugate polymer. Iodine-doped TCP (I-TCP) nanoparticles were prepard by blending TCP nanoparticles and iodine in ethanol solution. The effects of doped modification on the microstructure, physical properties, visible catalytic activity of the TiO2 nanoparticles were investigated. The results showed that the doped modification does not alter the crystalline structure, dispersivity and size of the TiO2 nanoparticles, while greatly improves the absorbancy of the nanocomposites in the range of visible light. Meanwhile, the effects of doping agent concentration, doping time and doping temperature on MO photodegradation with I-TCP nanocomposites as visible light photocatalyst were investigated. The photodegradation mechanism of MO in the presence of I-TCP was also discussed.