Preparation Of Ordered Mesoporous Titanium Dioxide And Its Application In Leather Dyeing Wastewater

As a new type of inorganic material, mesoporous TiO2is of high specific surface area, uniform pore size distribution and good oxidizing and photocatalytic performance, etc.. So it is widely used in environmental management. In this paper, mesoporous TiO2were synthesized via sol-gel route and hydrothermal method. Besides, doped mesoporous TiO2were synthesized in order to further expand the utilization of visible light. The crystal form, morphology and BET of products were characterized by Scanning Electron Microscopy, X-Ray Diffraction, BET surface area measurement and UV-vis diffuse reflection spectra, etc.. Acid black ATT solution and leather dyeing wastewater were used as target degradation products to investigate the photocatalytic performance of the as-prepared samples. The main results were listed as follows:1. The influences of the molar ratio of hydrochloride acid, ammonium hydroxide, water and PI23with tetra-n-butyl were investigated, while the influences of different alcohol, titanium, surfactant and calcined temperature were also investigated in the process of synthesized mesoporous TiO2via the sol-gel route. Mesoporous TiO2with high photocatalytic activity were obtained by the synthetic conditions as follows:ethanol as solvent, PI23as template, calcined temperature was500℃and the molar ratio of hydrochloride acid, water and PI23with tetra-n-butyl was0.05,0.0029and3.78respectively. Leather wastewater were treated with1g/L particles prepared as above and3%H2O2, after photodegradation for6h under365nm UV lamp, the decolorization rate were100%and the COD oxidation rate reached57.02%. The color of wastewater turned into clarified and the organic substance were decomposed in a great extent after treating the wastewater in sunlight with the coordination of mesoporous TiO2and H2O2.2. Anatase mesoporous TiO2were synthesized by hydrothermal method with tetra-n-butyl titanate as a precursor and surfactant PI23as a template. The structure and properties of mesoporous TiO2were changed while the hydrothermal conditions were changed. The optimum preparation conditions were as follows:the pH of reaction system was9, the hydrothermal temperature was140℃, the hydrothermal time was4h, and these results were obtained by the photocatalytic experiment. The samples were compared with those synthesized by sol-gel method in the same photocatalytic conditions and the illumination time was4h. The color and COD removal rate of tannery wastewater were99.53%and65.56%respectively, the consequences revealed that mesoporous TiO2synthesized by hydrothermal method also has good photocatalytic activity.3. At first, ferroferric oxide particles with magnetic responsibility were prepared by coprecipitation method. Afterwards, magnetic mesoporous TiO2composite particles were synthesized by sol-gel method with the mixed of ferroferric oxide particles, tetra-n-butyl and P123. The results showed that the decolorizing efficiency and COD removal rate of tannery wastewater was87%and42%respectively, after illuminating for5h at the dosage of composite particle was3g/L with doping amount of Fe3O4was8%, and the wavelength of UV light was254nm. Compared with non-magnetic particles, it is easier to recycle.4. Transition metal doped TiO2were synthesized by sol-gel method with tetra-n-butyl titanate as precursor and surfactant PI23as template. The results showed that different transition metal corresponding to different optimal doping amount and the photocatalytic activity order of the four transition metal were Mn>Fe>Ni>Co2+under their optimal doping amount. When the doping amount of Mn was0.4%and the dosage of Mn-doped particle was1g/L, the color removal rate of tannery wastewater was88.37%after illuminating for8h by visible light. Using sunlight as illuminant, the color removal rate of tannery wastewater was87.50%after photodegradation for18h.