Preparation Of Titania Pillared Montmorillonite Composite Photocatalysis And Study On Photocatalytic Of Methylene Blue

Treatment of dyeing wastewater has become a very serious problem for shortage of water resource in our country. In view of this, how to effectively and quickly solve this problem has become a focus of study domestic and overseas. Recently years, studies show that photocatalytic technology treatment has a high degradation efficiency on dyeing wastewater. For its advantage of safety, nontoxic, stable chemical property, economic cost and high photocatalytic activity, TiO₂ has a great developing space on its photocatalytic degradation of organic dyes in wastewater. However, there are some problems such as loss of catalysty and low absorption of visible light in TiO₂ limit its application and development.Montmorillonite has a larger specific surface area, higher cation exchange capacity and stronger adsorption ability. Therefore, the hybrid of two composite is a new way to improve photocatalytic degradation efficiency.In this research, TiO₂ pillared montmorillonite composite photocatalysis（TiO₂-MMT）were prepared by sol-gel method in anhydrous ethanol solvent for higher photocatalytic degradation on methylene blue, larger specific surface area and adsorption of montmorillonite of TiO₂. The preparation of N, S doped TiO₂ pillared montmorillonite composite photocatalysis（N/S-TiO₂-MMT） and graphene doped TiO₂ pillared montmorillonite composite photocatalysis（C-TiO₂-MMT） with the doping of N, S and graphene respectively. At the same time, we characterized its internal structure and surface morphology and studied its photocatalytic avtivity by degradation rate of methylene blue.The main research contents include the followings:Section 1. TiO₂-MMT composite photocatalysis were prepared under the acid condition by sol-gel method using butyl titanate as titanium source, anhydrous ethanol as solvent.Study the optimum process conditions of the preparation: the concentration of montmorillonite suspension is 1%, the ratio of Ti/MMT is 15 mmol/g, calcination temperature is 500℃, calcination time is 2h. Besides, investigated the effect of different factors such as concentration of methylene blue solution, pH, temperature and the dosing quantity of photocatalysis to adsorption of methylene blue and adsorption mechanism was discussed. The studies show that photocatalysis has a obviously adsorption on methylene blue. While the concentration of methylene blue solution is 15mmol/L, pH is 9, temperature is 25℃, the dosing quantity of photocatalysis is 1.5g/L, the photocatalytic degradation rate can reach 84.4% in visible light. In addition, methylene blue adsorption system is accord withthe second-order reaction kinetics equation. The adsorption of TiO₂-MMT composite photocatalysis significantly higher than that of TiO₂.Section 2. N/S-TiO₂-MMT composite photocatalysis were prepared under the acid condition by sol-gel method using butyl titanate as titanium source, anhydrous ethanol as solvent with the doping of N and S elements. Study the optimum process conditions of the preparation: n（N）:n（S）:n（Ti）=3:1:4, Calcination temperature is 500℃, Calcination time is 2h.Investigated the effect of different factors such as concentration of methylene blue solution,pH, temperature and the dosing quantity of photocatalysis to adsorption of methylene blue.At the same reaction conditions, the photocatalytic degradation rate can reach 89.0%. The experiments show that the doping of N, S element further improves photocatalytic activity.Section 3. C-TiO₂-MMT composite photocatalysis were prepared by the same method with the doping of graphene. Study the optimum process conditions of the preparation: The doping amount graphene is 2%, Calcination temperature is 500℃, Calcination time is 2h.Investigated the effect of different factors such as concentration of methylene blue solution,pH, temperature and the dosing quantity of photocatalysis to adsorption of methylene blue.At the same reaction conditions, the photocatalytic degradation rate can reach 94.2%. The experiments show that the doping of graphene significantly improves photocatalytic activity.Section 4. Investigated the photocatalytic activity of TiO₂-MMT, N/S-TiO₂-MMT and C-TiO₂-MMT composite photocatalysis respectively by different light source. The results show that the photocatalytic degradation rate of the three kinds photocatalysis were 90%,92.1%, 96% in uv light, respectively. They were slightly higher than the visible light which photocatalytic degradation rate were 84.4%, 89%, 94.2%. TiO₂ with the doping of N, S or graphene all further enhance the light absorption ability.This paper characterized the structure, morphology and optical properties of materials by using X-ray diffraction（XRD）, infrared spectroscopy（FT-IR） and ultraviolet spectrum（UV）, scanning electron microscope（SEM）, thermogravimetric（TG）, pore size distribution analysis（BET）, X-ray photoelectron spectroscopy（XPS） analysis testing methods, and study the effect of relevant conditions and synthetic parameters which work on the photocatalytic properties of the materials, as well as photocatalytic mechanism. The experimental studies show that TiO₂ successly pillared in MTT layers. The specific surface area of MMT,TiO₂-MMT, N/S-TiO₂-MMT, C-TiO₂-MMT composite photocatalysis were increasing in sequence, which is demonstrated the previous conclusion of photocatalytic degradation. It was observed that the photocatalysts in this study had a strong stability. After reusing the photocatalytic properties of photocatalysis were still well.