The Research Of Solid Phase Synthesis And Property Of Titanium Dioxide Supported On Rice Husk Rha

TiO2,as an excellent photocatalyst because of its high stability, inexpensive, resistance to acid and alkaline corrosion, good chemical stability and non-toxic, it has been used to remove of refractory organic pollutants from wastewater, such as azo dyes, rhodamine, phennol, nitrobenzene, etc. Currently, it has been widely studied and applied all around the world. This thesis used dehydrate titanyl sulfate as titanium source, made it reacted with sodium oxalate at room temperature by means of mechanical grind, finally pure TiO2photocatalyst was synthesized. On this basis and combined with the support technology of TiO2, we prepared TiO2/RHA composite photocatalyst with rice husk ash as support. Analytic technics such as X-ray diffraction, thermo-gravimetric and differential scanning calorimetry analysis, scanning electron microscope, fourier transform infrared spectroscopy were used to characterize the microstructure and morphology of the TiO2photocatalyst and TiO2/RHA composite photocatalyst. Meanwhile, we studied the photochemical activity of the catalyst for methyl orange degradation. The main achievements of this study are summerized as follows:(1) The calcination temperature had a great influence on the structure and performance of TiO2photocatalyst TiO2photocatalyst materials had good crystal structures when calcined at400℃,500℃,550℃, as the temperature range from300～800℃, TiO2still exist in the form of anatase phase.(2) TiO2photocatalyst calcined at450℃had a relatively high photocatalytic activity, thus we chose450℃as the optimal calcination temperature.(3) The TiO2photocatalyst prepared at450℃were of rough surface, as well as relatively loose structure. In addition, the apparent acidity had an effect on the photochemical activity of the catalysts, with the increase of calcination temperature, the photodegradation rate constant of methyl orange decreased.(4) When pH was3.0, the initial concentration of methyl orange was20mg/L and the dosage of T1O2photocatalyst calcined at450℃was2.00g/L, the preferable photocatalytic efficiency was presented. After irradiated by UV-light for15min, the decolorization rate of methyl orange reached99.3%, at the same time, the dynamic linear fitting results showed that the degradation of methyl orange by TiO2photocatalyst follow the first-order kinetics equation.(5) The effect of cycling time on the photocatalytic degradation efficiency of methyl orange by TiO2photocatalyst was studied, the results showed that after using5times, TiO2photocatalyst still remained higher photochemical activity. Compared the XRD patterns of as-prepared TiO2photocatalyst with the samples after used5times, the structure of photocatalyst had not been changed.(6) TiO2/RHA composite photocatalyst samples were prepared at various Ti/Si molar ratio. TiO2and SiO2were partially connected in the form of Ti-O-Si bonds, TiO2existed in the form of anatase phase, and distributed uniformly on the surface of RHA.(7) The photocatalytic activity of TiO2/RHA composite photocatalyst was relatively high when the molar ratio of Ti/Si was1:3. When the initial concentration of methyl orange was25mg/L, the dosage of TiO2/RHA composite photocatalyst was1.50g/L, the preferable photocatalytic efficiency was appeared, compared these results with the degradation experiment results of methyl orange by TiO2photocatalyst (other conditions were unchanged), We founded that by adding proper amount of rice husk ash, the adsorption ability and the photo-degradation efficiency could be improved to some extent.