Dissertation > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic > Catalyst

Investigation on the Synthesis, Characterization and Photocatalystic Properties of TiO2Composite Nanoparticles

Author LiZuoZuo
Tutor NiGang
School Ningxia University
Course Applied Chemistry
Keywords TiO2 photocatalytic degradation Zn,S codoped fly ash or silica fume support molecularimprinting technique
CLC O643.36
Type Master's thesis
Year 2014
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With the development of the industry, the global environmental problems have become more and more serious. Industrial wastewater is the main problem we are facing, especially the electroplating, metallurgy, printing and dyeing wastewater. They will cause serious pollution once they are poured into the environment. What’s more, dyeing wastewater is one of the most difficult wastewater to deal with because of its characteristics of rich water, thick alkali, high content of organic pollutants and changeable water quality. So, it is really important to search for a kind of suitable catalyst. TiO2is an ideal catalyst with its advantages of chemical stability, easy making, low cost and insoluble in water. However, the TiO2produced by general chemical experiments has poor efficiency of catalytic and low selectivity, for its poor distribution and easy reunion. Besides, TiO2is a kind of semiconductor oxide, electrons and holes are easy to compound. Therefore, to solve these problems, the paper will study from the following chemical experiments.1、The nano-TiO2photocatalytic materials were prepared by Sol-gel method with Ti(OC4H9)4as the main raw material, C2H5(OH) as solvent, CH3COOH as inhibitor, HCl as anti-catalyst. The effects of solvent amount, water amount, inhibitory dose, gel temperature, stirring rate on the sol-gel process and gel time of TiO2were studied by orthogonal test, and synthetic process of stable sol and main factors of performance of nano-TiO2photocatalytic materials were summarized.The structure and morphology of the obtained samples were characterized by X-ray diffraction, scanning electron microscope.2、Using thiourea dioxide as sulfur source, zinc sulfate heptahydrate as zinc source,sulfur-doped titania photocatalyst,zinc-doped titania photocatalyst and sulfur-zinc-doped titania photocatalyst were prepared by sol-gel method. The photocatalytic activity of the samples was tested for degradation of methyl orange (MO) solutions. Researched the effect of photocatalytic activities by the different doping amounts.The samples had been characterized by infrared spectroscopy(IR), X-ray diffraction(XRD), diffuse reflectance ultraviolet visible(DRUV), X-fluorescence spectra(XRF). The results showed that photocatalytic activity of the doped TiO2was improved significantly,the co-doped catalyst shave anatase phase and the absorption intensity was enhanced obviously, the absorption edges of it shifted to visible light region,indicates that the N, S-codoped nanosize TiO2,was formed of a new impurity level.3、The Zn-S-TiO2/fly ash and Zn-S-TiO2/silica fume photocatalysts were prepared using sol-gel technique in this work. The photocatalytic activity of the samples was tested for degradation of methyl orange (MO) solutions. Researched the different doping amount and different loading capacity the effect of photocatalytic activities. The samples had been characterized by infrared spectroscopy(IR), X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM). The results showed that the photocatalytic activity of doped-load type catalyst is higher than the doped catalysts.The possible reason is that the load of fly ash or silica fume can decrease the reunion phenomenon of TiO2, improve the distribution of the particles, improve the photocatalytic performance.The load type catalyst appear characteristic diffraction peaks of carrier.It is prove that TiO2is loaded on the two carriers successfully. 4、Neutralred moleculary inmrinted polymers were prepared by Surface polymerization method using neutral red as templat, methacrylicas as functional monomer,ethylene glycol dimethacrylate as cross-linker, The effects of template, functional monomer and cross-linker were studied by orthogonal test,the best molar ratio is1:4:20,the degradation rate is the highest.The NE-imprinted TiO2catalyst,imprinted catalyst exhibited a selective catalytic activity for the photo-catalyzed degradation of target-substrate molecules.When degrading non-target-substarate molecules,the NE-imprinted TiO2catalysted a similar activity with the non-imprinted catalyst.

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