Study On Preparation And Photocatalytic Activity Of Novel Composite Nanomaterials

In recent years, with the development of economy, the global environmentalpollution is becoming more and more serious, all kinds of pollution, such as waterpollution, air pollution, solid waste pollution, especially water pollution has been aserious threat to human health. Especially the dye wastewater, organic dye is the textileand other production paint, ink, cosmetics and other products of the factory emissions ofmajor pollutants in wastewater. They not only have specific color, complex structure,and most of them are not easy degradation, with potential toxicity. The photocatalyticoxidation can be completely mineralize the organic compounds to inorganic compoundsCO2and H2O simple, without the second pollution. In recent years, using nanomaterialas catalyst was treated by environmental workers is the concern of countries on printingand dyeing wastewater by photocatalytic oxidation.Different content of TiO2composite photocatalytic materials TiO2-γ-AlOOH andTiO2-γ-Al2O3were prepared by a one-pot synthetic procedure using aluminumtri-sec-butoxide as a precursor. The as-synthesized samples were characterized by acollection of techniques such as transform-infrared spectrophotometer (FT-IR), X-raydiffraction (XRD), thermogravimetry and differential scanning calorimetry (TG-DSC),Nitrogen adsorption and desorption, and scanning electron microscopy (SEM).Photocatalytic activity of all naocomposites was evaluated with respect to thephotodecomposition of methyl orange and methylene blue under UV irradiation andalmost complete decolorization was eventually archived under optimal experimentalconditions.Conclusions presented in this thesis are summarized as follows:1. Composite photocatalytic materials TiO2-γ-AlOOH and TiO2-γ-Al2O3wereprepared by a one-pot synthetic procedure using aluminum tri-sec-butoxide as aprecursor. The as-synthesized samples were fully characterized by a series of analyticaltechniques. It was identified that aluminum oxyhydroxide (γ-AlOOH, or boehmite) andalumina were produced as aluminum matrix into which titania, commercially availableP25, was embedded. The two composites both have a larger pore size and specificsurface area, better adsorption performance, better hydrothermal stability. And theSpecific surface area of the composite material Ti-Al2O3-40is224m2/g, less than theTi-AlOOH-40, which is256m2/g. 2. The various factors that might influence the composite TiO2-γ-AlOOH andTiO2-γ-Al2O3were explored. It was found that the best conditions for photocatalyticdegradation were: catalyst dosage of0.25g/L, initial concentration of10mg/L, initialpH of6, the illumination time was130min. Under this condition photocatalyticdegradation efficiency reach to90%or more. Especially, for the TiO2-γ-AlOOHmaterial(TiO2: γ-AlOOH40/l00), the initial concentration of methyl orange of5mg/L,ultraviolet irradiation of100min, methyl orange removal rate reached99.4%.3. From the simulated dye adsorption and photocatalytic degradation experiments,we can conclude that the composite material have good adsorption and catalyticproperties. And composite materials retain good photocatalytic properties after itsrecovery by centrifugation.4. The composite photocatalytic materials TiO2-γ-AlOOH and TiO2-γ-Al2O3canreach adsorption equilibrium in40min and adsorption isotherms consistent withFreundlich model.5. Compared to TiO2-γ-AlOOH, The composite photocatalytic materialsTiO2-γ-AlOOH have the better photocatalytic activity.