Preparation, Modification And Photocatalytic Properties Of Nanometer Titanium Dioxide

As the global environmental pollution and the energy crisis appearing, the requirement of low energy consumption and high environmental protection function materials is more urgent. Due to the high activity, non-toxic, strong oxidation ability and good stability of TiO₂, it has become one of the most popular environmentally-friendly catalysts. There are many problems in the preparation of TiO₂ such as the high cost of raw materials, easy introduction of other impurity ions, difficulties in separation and recycling, low solar energy utilization of TiO₂ photocatalyst. This paper has done the preparation, modification and photocatalytic properties of the nanometer titanium dioxide for these problems. The paper consists of five parts:In the first chapter, the structures, properties, photocatalytic technology and load type of nanometer titanium dioxide were reviewed, as well as the studies of attapulgite in environmental protection. The purpose and significance in this paper were also summarized.In the second chapter, CaSO₄/TiO₂ powder was prepared by using TiOSO4 as raw material and using inorganic base Ca(OH) 2 as a precipitant,by strictly controlling the process conditions. The resulting samples were evaluated by degradation of activeness scarlet under UV lamp. The result indicated that the powder was an excellent catalyst in terms of energy efficiency and the environmental protection.In the third chapter, with attapulgite as the carrier and TiOSO₄ as the titanium, attapulgite/TiO₂ nanocomposite was prepared by ultrasonic dispersion and precipitation technique. The resulting samples were characterized by using XRD, FT-IR, EDS and TEM. The photocatalytic activities were evaluated by degradation of activeness scarlet. The influence of the different proportion of attapulgite and TiO₂, the calcined temperature were studied in detail. Meanwhile, photocatalytic activity of the composite compared with pure TiO₂ and attapulgite. The results showed that attapulgite as the carrier, it not only can achieve the immobilization on TiO₂, but also can improve the efficiency of photocatalytic degradation and reduce wastewater treatment costs.In the fourth chapter, the attapulgite/ZnO-TiO₂ nano-composite was prepared by chemical precipitation using titanyl sulfate, zinc sulfate, ammonium carbonate as source materials and attapulgite as the carrier. The resulting samples were characterized by XRD, FT-IR, EDS, SEM, TEM and UV-Vis. The photocatalytic activities were evaluated by degradation of activeness scarlet and the conditions for preparing this composite were optimized. The results showed that the suitable conditions for preparation of the nano-composite were: the mass ratio of attapulgite and TiO₂ was 1:4, the molar ratio of TiO₂ and ZnO was 10:1, the calcined temperature was 450℃. Under these experimental conditions, photocatalytic activity of composite was the best. Compared with attapulgite/TiO₂ and attapulgite/ZnO, the nano-composite had good photocatalytic performance under visible light.In the fifth chapter, conclusion.