Preparation And Its Photocatalytic Application Of Zn-Ce-Ti Composites Oxides

Nano- ZnO, CeO2, TiO2 are utilized as inorganic UV absorbers because of its high chemical stability, thermal stability, non-migratory, tasteless, non-toxic, non-irritating, so it is safer to use. They are easily colored as a kind of light-colored powder. They can absorb stronger ultraviolet and transmit visible light, can shield for UVA, UVB. Thus the inorganic UV agents such as nano-ZnO, CeO2, TiO2 materials has stepped up the world stage, and gradually replaced some organic UV absorbers.The cerium nitrate, zinc nitrate, titanium trichloride as raw material, monomer oxides was prepared by combustion using ascorbic acid as burning agent. Effects of molar ratios of burning agent and metal elements on composites were investigated. With raw materials of titanium sulfate, cerium sulfate and zinc sulfate and precipitants agent of ammonium carbonate and urea, nanocomposite was prepared by heterogeneous nucleation-precipitation method. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, UV-visible spectrophotometer, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis. The composite oxides were modified by organic reagents, which were applied to improve the light stability of paraffin. In this paper, modified conditions of every composite oxide and the optimal processing conditions of paraffin light stability were studied.The CeO2 and TiO2 were prepared by combustion. The Ti/Ce composite was prepared by heterogeneous nucleation-precipitation method. The Ti/Ce composites were modified by coupling agent of organic titanate were mutually soluble with paraffin. That the inorganic UV agent is applied in organic phase has become a reality. The experiment showed the lipophilicity of TiO2/CeO2 and CeO2/TiO2 is attained to 56.3% and 60.3% respectively under optimal modifying temperature, amount of modifier, pH and time with coupling agent of organic titanate as modifier. The Ti/Ce composite oxides were applied in photocatalytic experiment with methylene blue as degradation aim. The degradation of methylene blue had been completed within 240 min and 300 min under optimal the dosage of catalyst, pH, rotation speed of centrifuge of TiO2/CeO2 and CeO2/TiO2 respectively.The CeO2, ZnO was prepared by combustion. The Zn/Ce composite was prepared by heterogeneous nucleation-precipitation method. The CeO2 coated ZnO in ZnO/CeO2 composite oxides. The CeO2 adhered to ZnO in CeO2/ZnO composite oxides. The experiment showed the lipophilicities of ZnO/CeO2 and CeO2/ZnO have increased to 61% and 58% respectively under optimal modifying temperature, amount of modifier, pH with sodium lauryl sulfate (SDBS) as modifier. The size of particle modified has become significantly smaller, its solubility is enhanced in the matrix, its use is expanded. The Zn/Ce composite oxides were applied for photocatalytic experiment with rhodamine B as degradation aim. The rhodamine B is completely degraded with photcatalyst of ZnO/CeO2 and CeO2/ZnO composite as photo-catalyst within 240 min and 3 hours respectively under optimal the dosage of catalyst, pH, rotation speed of centrifuge.With raw materials of Zn (NO3)2·7H2O, Ce(NO3)3·6H2O and TiCl3, ZnO-CeO2-TiO2 composite oxide was rapidly synthesized by the combustion method using ascorbic acid as combustion agent. The samples were characterized by XRD, FI-IR, UV-Vis and SEM. In the experiment, the effect of molar ratio of burning agent, cerium, titanium and zinc ions on crystalline of ZnO-CeO2-TiO2 composite was investigated. The results showed the composite with different ratio molar of burning agent and metal elements displayed different morphology and properties. The composite was applied to photocatalysis, decolorization and modification. The photocatalytic experiment studied using ZnO-CeO2-TiO2 composite with molar ratio of metal elements is 4:0.25:1 as photocatalyst and methylene blue as degradation aim. The solution completely degraded within 60 min under optimal photocatalytic conditions. The catalyst could be reused three times. The ZnO-CeO2-TiO2 composite with molar ratio of metal elements is 1:0.25:1, which was utilized as decolorizing agent displayed good decoloring ability. The experiment showed the lipophilicity of ZnO-CeO2-TiO2 composite has reached 87% under optimal modifying conditions.The modified composite oxides were applied to improve the light stability of paraffin. The light-stability of paraffin contained Ti/Ce and Zn/Ce composites remained unchanged in 10 min under irradiation of stronger ultraviolet light. Likewise the light-stability of paraffin contained ZnO-CeO2-TiO2 composite unchanged in 20 min. The light stability of paraffin was effectively improved by adding modified composites.