Study On Preparation And Degradation Of Organic Pollutant Of Doping Nanometer TiO₂ Immobilized On Carbon Sorbent

In the current work, the influence on preparing condition using the different large surface area material as supports, such as granular actived carbons and actived carbon fibers to the photocatalytic degradation performance activity have been investigated. Some new progresses were expected in the practical applications of photocatalytic technology.Fe³⁺ doped nanometer TiO₂ photocatalysts was prepared with different content ferric citrate and different opposite anions of Fe using the Ti(SO₄)₂ precipitation method. the precursor of TiO₂ was dried over steam bath at 80℃with ultrasonic wave, then was calcined to form the high photocatalytic activities of nanometer Fe³⁺ doped TiO₂. The photocatalyst acitivity results indicated that the optimum doping amount of iron ion when doping ferric citrate was 0.05 mole% under UV and solar light and the photocatlytic activity even higher than that of Degussa P25 TiO₂,Over 1% Fe content doped TiO₂ powders showed a strong absorption in whole range 350-500 nm and a red shift in the band gap but showed the weaker photocatalytic activity. SO₄^2- ion doping can improve the photocatalytic degradation of TiO₂ and have better activity than that of doped with other different kind inorganic anions of Fe³⁺ salt. The photocatalyst acitivity of nanometer titanium dioxide/ carbon material (TiO₂/C) was prepared by dip-coating technique by means of orthogonal experimental method. The effects of the conditions of prepared TiO₂/C catalyst on the photoelectrocatalysis degradation of methyl orange solution was investigated. The result was obtained that the specific surface areas of supporter play a decisive role in the degradation efficiency of methyl orange. The nano-sized TiO₂ was supported on active carbon (AC) were prepared by means of orthogonal experimental method too. The result showed that main influencing factor of photocatalysis activity was the doping amount of B³⁺ and H₂SO₄, and the effect of Fe³⁺ was much less. The kinetics of this degradation reaction conform to the Langmiur-Hinshelwood pseudo-first order kinetics model very well, and the absorption of OM on the prepared catalyst surface was the controlling step in the whole degradation process.The adsorption and regeneration characteristics of TiO₂ supported on granular activated carbon were studied by using the electrical catalytic degradation, using methylene blue as a model organic pollutant. At the room temperature and electric voltage of 80V, the relation between removal efficiency and the loaded mass of TiO₂ was measured. The TOC removal in tap water was also used to test the efficiency packed both TiO₂/GAC and GAC into a packed-bed reactor as an adsorbent and catalyst in the electrochemical reaction. The experimental results show that loaded TiO₂ on GAC enhanced the electrical catalytic adsorption and regeneration capacity. That is, the more mass was loaded, the better regenerating performance was got, and the best TOC removal was obtained when ratio of TiO₂ to GAC was 0.8:1.The TiO₂ photocatalyst were prepared by using dip-coating technique adhered precursor of TiO₂ to active carbon fiber and porous nickel mesh. The effects of different prepared factors, such as different supported materials, the times of coating, the calcining temperature and the added amount of H₂SO₄ were studied in photocatalytic oxidation of Benzene. The result showed that the ACF loaded with precursor of TiO₂ should be coated two times, calcined for 1 hours at 250℃and added proper amount of H2SO4. In this study, the optimum Fe³⁺ doping amount was ontained at 0.10%. And the kinetics of this degradation reaction of Benzene also corform to the Langmiur-Hinshelwood pseudo-first order kinetics model very well.