【作者】 祝洪奎；

【导师】 姜兆华；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2008， 硕士

【摘要】 随着工业的发展,人类本已有限的水资源受到日益严重的污染,尤其是重金属废水中的Cr（VI）污染对人们的身体健康危害极大。因此清除水体中的Cr（VI）已成为环保领域的一项重要工作。近年来逐渐发展起来的光催化技术,因其能耗低、操作简单、可减少二次污染等优点,引起了研究者的广泛关注,被认为是实现人类可持续发展的环境友好的水处理技术。本文采用阳极氧化法以H2SO4体系为电解液在钛基体上原位生长了一层多孔TiO₂膜。结合对铬酸钾的光催化还原效率,对这种体系制备的TiO₂膜的工艺参数（电解液浓度、电流密度、电压）对膜层结构、表面形貌以及铬酸钾的还原率进行了研究。结果表明,当电解液浓度为0.5mol/L、电流密度为100mA/cm2和电压为200V时所制备的膜层有较高的光催化还原活性。为了进一步提高TiO₂膜的光催化还原活性,分别对TiO₂膜进行掺杂改性和焙烧-酸化改性。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、电子探针显微分析（EPMA）等表征手段,并结合TiO₂膜对铬酸钾光催化还原效果的分析,研制出高活性的改性TiO₂催化剂。结果表明,当向H2SO4体系中掺杂0.2g/L的硫酸锌时和焙烧温度在873K、焙烧时间为30min、用浓H2SO4活化1h时具有较高的光催化还原活性,对铬酸钾的还原率均在95%以上。在光催化还原反应系统中,对pH值、紫外灯功率、反应物初始浓度、空穴捕获剂等因素对铬酸钾还原率的影响进行了研究,并对铬酸钾还原动力学进行初步探讨。结果表明TiO₂膜对铬酸钾的还原符合Langmuir-Hinshlwood反应动力学方程,10-50mg/L的铬酸钾的还原符合表观一级动力学方程。并对铬酸钾的还原产物进行了分析,结果表明Cr（VI）经光催化还原后的产物为Cr（III）,并且Cr（III）以Cr（OH）3的形式存在。更多还原

【Abstract】 With the development of the industry, the limited water source is polluted seriously day by day, especially for Cr（VI） in the waste water has threatened our health straightly. So eliminating Cr（VI） in the water has become an important work of the environment protection. In recent years, the photocatalytic degradation is consided as an environmental friendly technique to deal with the waste water because of its low energy expense, no secondary pollution and easy operation process etc. Therefore, much attention has been paid by the researchers.In this paper, films were produced on Ti substrate with anodic oxidation method in H2SO4 electrolyte. Process parameters （electrolyte concentration, current density and voltage） were optimized according to the photocatalytic reduction efficiency of chromate potassium. The results showed that TiO₂ films prepared in the electrolyte of H2SO4 （0.5mol/L）, the current density at 100mA/cm2 and the voltage at 200v had higher photocatalytic activity.In order to improve photocatalytic activity of the TiO₂ films, differdent additives were doped into the electrolyte of H2SO4 or the produced films were post-calcined under different temperature. The technique parameters for the preparation of the the high-activity modified TiO₂ catalyst were optimized by using SEM、XRD and EPMA, as well as the results of the photo reduction ratio and. The results showed that 0.2 g/L ZnSO4 dopant in the electrolyte of H2SO4 made the photo reduction ratio of the modified TiO₂ catalyst up to 98%, and the post-calcinations at 873K for 30min with the following activity for 1h in H2SO4 improved the photo reduction ratio of the modified TiO₂ catalyst to 96%.In the photocatalysis reduction system, the effects of pH, Ultraviolet lamp power, the start concentration of the chromate potassium and the cavity seizing materials on the photo reduction ratio of the chromate patassium were researched, and the reduction kinetic of the chromate potassium was discussed prelimarily. The results showed that photocatalytic reduction of TiO₂ films for chromate potassium complied with the kinetic equation of Langumuir-Hinshlwood. When the concentration of chromate potassium was at 10-50 mg/L, the reduction process complied with the first-order reaction. The analysis of the reduction substance of chromate potassium showed that the Cr（VI） was reduced into Cr（III） which existed in the form of Cr（OH）₃.更多还原