The Technical Study Of Nano-TiO₂ Photocatalytic Oxidation Desulfurization

A series of nanometer titanium dioxide (TiO2) and doped TiO2 were prepared by sol - gel method, in which were doped of transition metal (Fe, Ni, Cu, Zn),rare earth (La, Ce, Eu), precious metals (Ag) and non-metallic (N).Characterized by TG-DTA, XRD, BET, UV-VIS, doped TiO2 was in comparison with pure TiO2. The results showed that the performance of doped TiO2 had occurred a marked change : phase change temperature increased ,La-TiO2 calcined at 700℃had not yet occurred phase change, phase transitional temperature of pure TiO2 was 500 to 600℃); the size of the particle reduced (calcined at 500℃); doped TiO2 had larger BET surface area; the absorption spectra were shifted to visible redshift (exception of Zn).The reaction conditions of the TiO2 photocatalytic desulfurization of dibenzothiophene(DBT) adopted as the model compound were studied . Formic acid as the solvent, tetrabutyl ammonium bromide as phase transfer agent, TiO2 as photocatalyst, the optimal reaction conditions were as follows: the volume ratio of formic acid and model compounds was 1:1, the amount of tetrabutyl ammonium bromide was 0.5 g / L, the amount of TiO2 was 2.0 g / L and reaction time was 3 h.Desulfurization reaction in the best conditions, the photocatalytic activity of TiO2 and doped TiO2 oxidatively removal sulfide from atmospheric, vacuum distillation gasoline and model compounds of Benzothiophene, dibenzothiophene were studied. The results showed that the optimal volume of doped Fe, Ni, Cu, Zn, La, Ce, Eu, Ag and N of TiO2 in the oxidation of Benzothio as photocatalysis respectively was 0.03%, 7.5%, 5.0%, 2.0%, 1.5%, 2.0%, 1.0%, 0.5% and 300% ( molar ratio to TiO2 ) . The desulfurization rate ,using 7.5% Ni-TiO2 removal sulfide from model compounds of Benzothiophene, was closed to 98.4%. The optimal volume of doped Fe, Ni, Cu, Zn, La, Ce, Eu, Ag and N of TiO2 in the process of photocatalyting, oxidating atmospheric and vacuum distillation gasoline respectively was 0.03%, 5.0%, 5.0%, 1.0%, 0.5%, 1.0%, 0.5%, 0.1% and 100%.1.0% Zn-TiO2,the desulfurization rate of atmospheric and vacuum distillation gasoline was 81.0%. The desulfurization rate ,using doped TiO2 removal sulfide from model compounds of dibenzothiophene, was closed to 42.4%.