Study On Preparation And Photocalytic Properties Of Metal Oxide/Anion Exchange Resin

In recent years, photocatalytic oxidation technology is paid greater attention to the researchers because of mild reaction conditions, easy to control of operation process, available sunlight as the light source, completely degradation of organic matter, etc. At present photocatalysts of commonly used are mainly some metal oxide semiconductors. The semiconductor materials had many defects, such as narrow of light response range, easy complex of electronic-hole, difficult of separation and reuse, so it is difficult to achieve the ideal effect. To preparation catalyst of excellent properties, we are constantly explore in the field of photocatalysis.This paper reviewed the progress on development and application of semiconductor photocatalyst technology. The commonly used semiconductor photocatalyst, modification, carrier, factors affecting photocatalytic activity and preparation methods of the catalysts were introduced. Several oxide (composite metal oxides)/anion exchange resin composite semiconductor photocatalysts were synthesized respectively by photocatalytic performance of metal oxide or its compounds and adsorption character of type 717 anion exchange resin. The surface morphology and spectroscopy properties of composite photocatalyst was characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), energy scattering (EDS), infrared spectra (FTIR). Its photocatalytic properties to degradation of methyl orange were investigated.(1) TiO2/anion exchange resin(AER) composite photocatalyst was prepared by solvent hot method,using butyl titanate and anhydrous ethanol as precursors and solvent respectively,717 anion exchange resin as carrier. TiO2 particles of anatase phase load the AER surface in the way of chemical bond. The TiO2/AER presents preferable photocatalytic property and reusability by the interaction between the adsorptivity of AER and the photocatalytic activity of TiO2. The activity of TiO2/AER composite photocatalyst was the highest when ratio of Ti4+ and OH- was 1:4 and reaction time was 18h. The decolorization rate of methyl orange, when 300W high pressure mercury lamp was used as light source, the pH value of solution was 4 and the amount of TiO2/AER was 0.06g, can reach 96.09%. The reusability results show that the decolorization of methyl orange was due to the adsorption enrichment of AER and degradation by TiO2 rather than easy adsorption on AER. The stability, reusability and separation and recycled of TiO2/AER was better than TiO2.(2) SnO2/TiO2/AER composite photocatalyst was synthesized with anion exchange resin, Na2SnO3-4H2O, Ti(SO4)2 and NH3H2O. The compound semiconductor of rutile SnO2 and anatase TiO2 load on AER. The activity of SnO2/TiO2/AER was the highest when the amount of AER was 5g, n(SnO32-)/n(Ti4+)=1:4 and the reaction temperature was 100℃. The decolorization rate of methyl orange, when 300W high pressure mercury lamp was used as light source, the pH value of solution was 4 and the amount of SnO2/TiO2/AER was 0.04g, could reach 94.84%. After repeated ten times, composite photocatalyst was still for the degradation rate of methyl orange more than 90%.(3) SnO2/ZnO/AER composite photocatalyst was synthesized with anion exchange resin, Na2SnO3·4H2O, ZnCl2 and NH4OH. The presence of coordination interaction between AER and SnO2 (tetragonal phase)/ZnO (hexagonal system fiber catalpa ore structure) compound semiconductor. It is the optimal synthesis condition that the reaction temperature was 80℃, n(SnO32-)/n(Zn2+)=l:2 and the amount of AER was 4g. The decolorization rate of methyl orange, when the pH value of solution was 6 and the amount of SnO2/ZnO/AER was 0.04g, could reach 94.15% after 300W xenon lamp irradiation for 2h. After repeated eight times, composite photocatalyst for the degradation rate of methyl orange was still more than 90%.