Study On FeOOH/TiO₂/Mmt Nanocomposite's Manufacture And Photocatalytic Degradation On Methyl Orange

Organic pollutants has been concerned in worldwide. Photocatalytic technology brings a new way to organic pollutants treatment, related research has shown that nearly Almost environment organic pollutants in environment can be degrade in some extent.In this thesis, we take the Sol-gel method to prepare TiO₂/Montmorillonite (TiO₂/Mmt) composite, then put this composite into Fe(NO₃)₃-HNO₃ , by the Hydrolysis of Fe³⁺, a-FeOOH was crystallized on TiO₂/Mmt composite. So to form nano- FeOOH/ TiO₂/Mmt composite. In deeper, contrastive research of methyl orange water solution by using these materials was taken. The progress of our study is shown as follows:1. TiO₂/Mmt composite was. prepared by Sol-gel method and the best parameters are: The ratio of Ti(â…£) to montmorillonite was 15mmol/g, and the mass concentration of montmofillonite suspension was 3%. The composite system was prepared at 25℃, and finally calcined at 450 C for 1h. FeOOH was Crystallized on TiO₂/Mmt composite in Fe(NO3)3-HNO3 system and the reasonable parameters are: concentration of Fe(NO₃)₃ was 2.0mM, pH-2.10, 60℃.TEM analyse showed that, the 5～10nm TiO₂ on Mmt was anatase,and the crystal on TiO₂/Mmt surface was goethite(5～25nm)2. When dispose Methyl Orange in water solution, FeOOH/TiO₂/Mmt/H₂O₂/UV system and FeOOH/TiO₂/Mmt/ H₂O₂/Visible light system have both good effect on photocatalysis methyl orange, after 1h reaction time, decoloration rate of methyl orange solution were 94% and 99%.3 FTIR spectra of MO disposed by the two system related above showes: the charasteristic wave numbers at 1420cm^-1 belongs to azo bond,.1540.1450 cm^-1 belongs to benzene rings, and 1380cm^-1belongs to C-N bond. After 1h reaction time,The peak at 1420cm^-1 disappeared ,and the peak at 1540. 1450 cm^-1 get weak, the peak at 1380 cm^-1 become strong, so we come to a conclusion that the azo bond of methyl orange molecules adsorbed on the surface of iron oxyhydroxides ruptured, and the benzene rings of most methyl orange molecules were opened to form a series of little molecules. However the curve responding to FeOOH/TiO₂/Mmt/H₂O₂/UV system changed more in peak's strength than FeOOH/TiO₂/Mmt/H₂O₂/Visible light system, it showed FeOOH/TiO₂/Mmt/H₂O₂/UV system had better degradation effect on MO than FeOOH/TiO₂/Mmt/H₂O₂/Visible light system4. FeOOH/TiO₂/Mmt/H₂O₂/Visible light system had higher decoloration rate but had worse degradation effect on disposing MO solution than FeOOH/TiO₂/Mmt/H₂O₂/UV system, so For azo dyes's Photocatalytic Degradation, we can not evaluate the extent of degradation degree by decoloration rate, because it 's easy to break the azo bond to make the color to solution turn light, but it does not mean that degradation has the similar degree to decoloration rate. We used quantitative KBr adsorption certain volume of methyl solution that had been disposed, drying this solution at room temperature in vacuum condition, so to form infrared spectra certain samples for infrared spectra. By Observe the changes on organic molecular structure through high-sensitivity FTIR analysis to research the changes of organic molecular structure that absorbed on samples, revealing the photocatalytic process of trace organics in solid / liquid interface in a some extent.5. As the existence of FeOOH, FeOOH/TiO2/Mmt composite can corresponding a larger range of optical wavelength than TiO2/Mmt composite, so FeOOH/TiO2/Mmt/H2O2 system has good effect on photocatalysis on methyl orange in visible light...