Papers by Keyword: Nanometer TiO₂

Abstract: The main purpose of the pavement coating is to reduce the haze by absorbing and degrading pm2.5 from automobile exhaust. Based on the investigation and analysis of the source and main composition of haze and pm2.5 and the physical and chemical properties of haze, the paper proposes the method of combining the absorption and catalytic degradation of active Al₂O₃ and nanometer TiO₂ together. Through the experiments, the pavement coating which has the different ratio of active Al₂O₃ and nanometer TiO₂ behaves differently on the effect of absorption and degradation of pm2.5, and the optimum dosage and ratio of active Al₂O₃ and nanometer TiO₂ was found finally. The pavement coating which use the optimum dosage has the more obvious effect under the ultraviolet. And the water resistance and skid resistance performance can also meet the requirements.

Abstract: In order to prepare high reflectivity titanium dioxide, by sol - gel method after nano-titanium dioxide powder, which silane coupling agent KH-570 covering it and make its surface modification.When the reaction temperature is 40 °C, drop accelerated rate 1.5mL/min, calcination temperature about 600 °C, got titanium dioxide with relatively high reflectivity and particle size in around 65 nm.When the amount of the silane coupling agent is 0.5%, the pH of reaction system is 6.5, and the reaction time was 1.5h, the nano-modified titanium dioxide particles with high reflectance.

Abstract: Nanometer titanium dioxide powders were prepared by hydrolysis of titanium-tetrabut- oxide with ethanol. Using the process that titanium alloys were embedded by the nanometer TiO₂ powders and sintered in the high temperature furnace, the nano-TiO2 / titanium alloy biomaterials was fabricated out. The particle size of TiO₂ particles on the surface of Ti alloy was mainly 50-70 nm. The experimental results indicated that the films of nanocrystalline titanium oxide powders on the surface of Ti alloy were with an excellent biocompatibility. By cultivation in the simulated body fluid for 7 days, the Ca phosphates were deposited on the specimen surface, and n (Ca) / n (P) atom ratio is about 1.61:1, which is similar to that of HA and human bone. The nano-TiO₂ / titanium alloy possessed favorable cell compatibility testified by the cell cultivation experiment.

Abstract: Titanium tetrachloride with inorganic salts as raw materials in the experiment, TiO₂ is prepared by the hydrolyzation method in (NH₄)₂SO₄-modified TiCl₄ solution, the maximal photocatalytic activity is observed at the mole ratio of TiCl₄: (NH₄)₂SO₄=1:2, the water-bath temperature of 90°C. Bromophenol blue solution is degraded by the nanometer TiO₂. The photocatalytic degradation efficiency is influenced by the nanometer TiO₂ amount, irradiation time, the UV irradiation intensity and solution temperature. The short degradation time shows that the nanometer TiO₂ can be used as an easy and efficient method to degrade bromophenol blue solution.

Abstract: In this paper, titanium tetrachloride with inorganic salts as raw materials in the experiment, TiO₂ is prepared by the hydrolyzation method in (NH₄)₂SO₄-modified TiCl₄ solution, the maximal photocatalytic activity is observed at the mole ratio of TiCl₄: (NH₄)₂SO₄=1:2, the water-bath temperature of 90°C. The photocatalytic degradation efficiency is influenced by the initial cresol red concentration, the solution pH, irradiation time and the UV irradiation intensity. The short degradation time shows that the nanometer TiO₂ can be used as an easy and efficient method to degrade the cresol red solution in wastewater.

Abstract: Cotton fabric is processed for anti-ultraviolet finishing by using nanometer TiO₂ of different crystalline structures, polyethylene glycol (PEG) and so on. The results show: under the same conditions, the adhesion amount of rutile nanometer TiO₂ is more than anatase nanometer TiO₂; with different TiO₂/PEG concentrations and different molecular weight of PEG, the adhesion amount of TiO₂ is different, furthermore both the laundry-resistant property and the photoaging property have different change.

Abstract: This study investigated the effect of cationic, anionic, and nonionic surfactants on the formation, morphology, and surface properties of TiO₂ nanoparticles synthesized by modified sol-gel method. The crystalline structures and morphologies of the powder have been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results showed TiO₂ nanoparticles synthesized with different surfactants only include anatase phase. The TEM analysis revealed the surfactants can enhance dispersion of TiO₂ nanoparticles. In contrast, the anionic surfactants showed hightly effects. The photocatalytic activity of samples was tested for degradation of methyl orange (MO) solutions. The results showed photocatalytic activity of the catalyst with surfactants was higher than pure TiO₂ under ultraviolet.

Abstract: TiO₂ photocatalyst and copper-doped titania (Cu/TiO₂) photocatalyst were prepared and both photocatalysts were used in the self-cleaning finishing of wall fabrics. XRD showed that the nanometer materials and textile wall fabrics were a good combination. By comparing the self-cleaning effects of two kinds of photocatalysts, the results demonstrate that textile wall fabrics finished with Cu²⁺-doped TiO₂ photocatalyst have better self-cleaning effect under visible light.

Abstract: Using the as-prepared SiO2 aerogels as carriers, SiO2 aerogel supported nano-TiO2 (TiO2/SiO2 aerogel) photocatalysts were prepared by sol-gel and adsorption loading process. The microstructure, morphology and properties of the obtained TiO2/SiO2 aerogel were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller (BET) N2 adsorption-desorption analysis. The adsorption/photocatalytic degradation for Rhodamine B of TiO2/SiO2 aerogel composite photocatalysts was investigated. The results indicate that TiO2 sol concentration is the main factor influencing the microstructure and properties of TiO2/SiO2 aerogel composite photocatalysts. With the increasing of TiO2 sol concentration, the amount of loaded TiO2 increased, but the specific surface area, pore volume and pore size gradually decreased. The specific surface area, pore volume and pore diameter of TiO2/SiO2 aerogel photocatalysts after annealed at 550oC are 444.76～750.34 m2/g, 0.08～0.70 m3/g and 2.46～4.58nm, respectively. The TiO2/SiO2 aerogel prepared with 0.75 mol/L TiO2 sol concentration has best adsorption/photocatalytic degradation for Rhdamine B.

Abstract: This paper investigates the effect of Limonite/TiO₂ combined microspheres dosage,solution pH, reaction time,light intensity on the removal rate of phenol in source water.Based on the single factor experiment, the experimental conditions are optimized by quadratic regression orthogonal rotation combination design.The quadratic orthogonal regression model of removal rate of phenol(y) to four factors of Limonite/TiO₂ combined microspheres dosage(x1),pH(x2),reaction time (x3)and light intensity (x4) is established as Y=88.64+4.43X₁+ 6.69X₃+3.75X₄-4.79X₁²-13.20X₂²-4.21X₃²-2.69X₄²+8.06X₁X₂-6.76X₁X₃-4.45X₁X₄.It can conclude from the model that when Limonite/TiO2 combined microspheres dosage is 1.5583g,solution pH value is 4.5095,reaction time is 102.12min,light intensity is 1710.8（x10 lux）,the yield(y) reaches the maximal(95.83%) and consistent with the confirmatory experiment result..