Study On Preparation And Surface Coating Of Rutile Titanium Dioxide

Due to the destruction of the ozone layer,the intensity of ultraviolet rays that can reach the earth is greatly increased,and the protection of the skin from ultraviolet rays has caused great concern.Rutile TiO₂ can absorb ultraviolet rays better,has the advantages of non-toxicity,strong stability and strong resistance to ultraviolet aging,etc.It is one of the most widely used ultraviolet shielding agents.The crystal structure and surface coating of TiO₂ are important factors affecting its UV shielding performance.However,it is difficult to control the crystal form of TiO₂,with a large band gap,poor dispersion,and photocatalytic activity.Based on the above disadvantages,in this work,rutile TiO₂ was synthesized via surfactant-assisted method by using titanium sulfate as titanium source,and rutile TiO₂ by silicon coating,cerium coating,and cerium-silicon coating treatment were studied.Factors associated with crystalline structure of TiO₂were investigated including surfactant type and concentration,and the effects of different coating agents on the ultraviolet shielding ability of titanium dioxide were studied.The main research contents and conclusions are as follows:（1）Rutile TiO₂ was prepared via surfactant-assisted method by using titanium sulfate as titanium source.The effects of surfactant types on the TiO₂ crystal form were investigated.The results showed that:anionic surfactants（sodium citrate and sodium dodecylbenzenesulfonate）didn’t promote transformation from anatase to rutile titania,and cationic surfactants（hexadecyltrimethylammonium bromide,dodecyl Triethylammonium chloride and benzyltriethylammonium chloride）played a decisive role in the formation of TiO₂,which promoted transformation from anatase to rutile titania.When cationic surfactant concentration was greater than the critical micelle concentration,the micellar surface formed by the cationic surfactant has a positive charge,electrostatic adsorption and the hypotenuse of the[Ti O₆]octahedron were chelated together,making the[Ti O₆]octahedron more inclined to grow on opposite sides.And the steric hindrance effect of the cationic group of the surfactant prevented the spiral growth of the[Ti O₆]octahedron,which promoting the the transformation from anatase to rutile titania.（2）The effects of surfactant concentration on the TiO₂ crystal form and ultraviolet shielding ability were studied.The results showed that the rutile phase appeared when the CTMAB feed concentration was greater than or equal to 3 mmol/L,and the rutile content was highest when the CTMAB feed concentration was 4 mmol/L.The rutile phase appeared in the product and the sample rutile content was the highest when the1231 feed concentration was equal to 10 mmol/L.When the benzyltriethylammonium chloride feed concentration was greater than or equal to 6 mmol/L,the product appeared the rutile phase and When the concentration of benzyltriethylammonium chloride was equal to 15 mmol/L,the sample had the highest rutile content.The rutile phase appeared in TiO₂ products,the ultraviolet absorption platform of the products rose,and the absorption capacity increased;the band gap width of the products decreased by 0.2～0.3 e V,and the absorption wavelength range increased.（3）The effects of single-component coating on the UV shielding ability of TiO₂were investigated.Optimum conditions for the silicon-coated:coating temperature=40℃,p H=9,the proportion of silicon coated with 0.03,Na₂Si O₃concentration of 0.01 mol/L.The ultraviolet shielding performance of TiO₂@SiO₂-3%decreased by 21%,and the electron-hole pair recombination rate increased.According to FDTD simulation,it can be seen that the generation rate of TiO₂@SiO₂ electron-hole pair decreases,and the weather resistance of the product increases.Optimal conditions for the coated cerium:p H=10,the coating temperature=50℃,Ce（SO₄）₂ concentration of 0.02 mol/L,the proportion of cerium coated with 0.03.The ultraviolet absorption platform value of TiO₂@CeO₂-3%increased by 54%,and the electron-hole pair recombination rate increased.According to FDTD simulation,it can be seen that the generation rate of TiO₂@CeO₂ electron-hole pairs increases,and the weather resistance of the product decreases.（4）The effects of composite coating on the ultraviolet shielding ability of TiO₂were studied.The results showed that the UV absorption platform value of TiO₂@SiO₂@CeO₂ increased by 61%compared to the single-component coating,the ultraviolet shielding ability was best,the electron-hole pair recombination rate increased the most,and the electron-hole pair generation rate was the lowest.The above research results can provide basic data for industrial design and scale-up of the rutile titanium dioxide preparation process,and have important scientific significance and use value.