【作者】 陈恩伟；

【导师】 银董红；

【作者基本信息】 湖南师范大学 ， 应用化学， 2006， 硕士

【摘要】 工业废水中有毒杂环化合物的处理是一个具有重大实用价值的研究课题。本文在综述二氧化钛光催化剂的制备和光催化氧化处理有机废水的基础上,较为系统的研究了二氧化钛光催化剂的制备、镧系元素离子改性二氧化钛及其在光催化降解咪唑中的应用。结果表明,采用溶胶-凝胶法制备的二氧化钛光催化降解杂环化合物咪唑,具有工艺设备简单,操作条件易控制,光源的利用率高,有效降解有毒污染物和无二次污染等突出优点,具体研究内容如下: （1）以四氯化钛为原料,采用溶胶-凝胶法制备TiO₂粉体,对比研究了不同的溶胶体系、焙烧温度等条件所制得的TiO₂粉体的光催化性能。结果表明,以乙醇为溶剂的溶胶体系,并在500℃空气气氛中焙烧2小时所得的TiO₂具有较高的催化活性,对咪唑的降解性能较好。 （2）为了进一步提高TiO₂的光催化活性,制备了La³⁺,Ce³⁺,Pr³⁺,Nd³⁺,Sm³⁺,Eu³⁺,Tb³⁺,Dy³⁺,Ho³⁺,Tm³⁺等不同镧系元素离子掺杂的TiO₂光催化剂,用X-射线衍射（XRD）,X-射线光电子能谱（XPS）,光致发光光谱（PLS）和表面光电压谱（SPS）等表征手段对掺杂改性的TiO₂进行了表征,并且在紫外光照射下测试了其光催化性能。结果表明稀土离子掺杂可以有效提高TiO₂表面光激发载流子的分离效果,从而提高了TiO₂的光催化活性。考察了不同稀土离子浓度对掺杂TiO₂光催化剂性能的影响规律,发现不同浓度Tb³⁺掺杂TiO₂的光催更多还原

【Abstract】 The treatment of deleterious heterocyclic compounds in industrial waste water is an important field. Based on the review of the preparation methods of TiO₂ and the photodegradation of organic waste water, the preparation of TiO₂ and lanthanide ions doped TiO₂ as well as their phototcatalytic application in the degradation of imidazole were studied systematically in this thesis. The results showed that photo-induced degradation of imidazole in the presence of TiO₂ photocatalysts has the prominent virtues, such as simple processing equipment and operation conditions controlled easily, effective degradation of organic pollutants and no secondary pollution. The main contents of the thesis were discussed as follows:（1）Titanium dioxide powder was prepared using TiCl₄ as precursor via sol-gel process. The influences of solvent system and calcination temperature on the catalytic performance of TiO₂ were investigated. It was found that the titanium dioxide powder prepared from ethanol solution and calcined at the temperature of 500℃ for two hours had high activity in the photocatalytic degradation of imidazole.（2）In order to improve the photocatalytic activity of TiO₂ photocatalyst, different lanthanide ions-doped TiO₂ including La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Tm³⁺ were prepared and characterized by X-ray diffraction（XRD）, X-ray photoelectronspectroscopy（XPS）, photoluminescence emission spectroscopy（PLS）, surface photovoltage spectra（SPS）. It was found that the lanthanide ions doped TiC>2 possessed more effective separation of the electron-hole pairs, giving higher photocatalytic activity in comparison with pure TiO2. Forthemore, the photocatalytic activity of Tb3+-doped TiO2 increased with an increase of concentration of Tb3+ less than 2%, and then decreased after the concentration of Tb3+ exceed 2%. The order of photocatalytic activity of various lanthanide ions doped TiC>2 samples was the same as the order of their SPS intensity, and the reverse as the order of their PLS intensity. Namely, stronger intensity of SPS and weaker intensity of PLS, mean that the doped-TiC>2 has higher photocatalytic activity. In conclusion, the intensity of SPS and PLS could be used as the criterion tocompare the photocatalytic activity of the semiconductors.（3）The kinetics of photocatalytic oxidation of imidazole over the2%Tb3+ doped TiC>2 photocatalyst were studied. The results indicated that oxidation of imidazole under UV light followed the first-order kinetic equation and that the rate of reaction was coincident with Langmuir-Hinshelwood equation. The kinetic equation obtained was l/r0=0.59122+83.088（l/C0）, and the parent rate;constant of k and the adsorption balance constant of K were 1.8062 mg/（L*min） and 6.663xlO"3L-mg"1, respectively..,.更多还原