The Preparation, Characterization Of Photocatalysis Material Tio₂ And The Application In Arsenic Adsorption

Titanium dioxide is used in various photocatalysis and oxidation processes because of its chemical stability, strong oxidation-reduction ability, high photoetch resistance, non-toxic and low cost. In water treatment, we can decompose organic and decrease the toxicity of inorganic based on the oxidation reactivity between TiO₂ and the waste water. In this paper we prepared titanium dioxide nano-particles and titanium dioxide membrane based on monocrystalline silicon for the As(â…¢) oxidation and the decomposition of organic compounds, simultaneously, we studied the characterization of the materials.Through the precipitation of butyl titanate which is selected as the precursor, different crystal types of TiO₂ particles were obtained after two-step heat treatment. We used spin-coating and sol-gel methods prepared different crystal types of TiO₂ membrane. In this study we carry out the characterization using some techniques:Laman and XRD spectrum to determine the crystal type of particle and the membrane, SEM to observe the membrane surface morphology, TEM to observe the morphology and size of particles, XPS to study the binding mode between TiO₂ and monocrystalline silicon ,even to carry out semi-quantitative study of membrane, UV-Vis spectrum to study the adsorption spectrum of TiO₂ particles and TiO2/Si, FTIR and TG/DTA to study the hydroxyl content of TiO₂ particles. We also measured the surface area of the particles and carry out adsorption kinetics experiment.The surface area of TiO₂ particles named B, A and R is 227.1㎡/g, 39.07㎡/g and 0.5972㎡/g respectively, the size arrange is 6 nm-12 nm,14 nm-36 nm and 18 nm-90 nm respectively. Material A has 100% anatase phase , 96.6% rutile phase for Material B, no single phase transformation temperature exists. The very important factors for adsorption capacity of TiO₂ are the surface area and hydroxyl content, adsorption capacity of materials B, A and R is 7.6 mg/g,3 mg/gå'Œ1.3 mg/g with the initial concentration about 2 mg/L respectively. B, A and R have strong photo-catalytic oxidation ability to promote the adsorption of As(â…¢) under ultraviolet ,this due to the joint adsorption of As(â…¢) and As(â…¤) in the solution .The optimum conditions for get TiO₂ membrane on monocrystalline silicon are: mole ratio 1.9% for butyl titanate and 1000 r/min. The membrane on silicon is well distributed, rough and a little fracture. The membrane thickness is below 5 nm and Si-O-Ti band exists. The phase form of TiO₂ membrane is different in different temperature, 100% anatase phase for 650℃, 98.2% brookite for 450℃. The substrate of Si can improve the thermal stability of anatase phase, so when the temperature reached 750℃there is no rutile phase in the membrane. TiO2/Si made from different temperature showed larger absorption range and stronger adsorption intensity of light than monocrystalline silicon and titanium dioxide, so material TiO2/Si has high utilization efficiency.