【作者】 粟丽苹；

【导师】 刘自力；

【作者基本信息】 广西大学 ， 化学工艺， 2004， 硕士

【摘要】 酚类化合物是一类很难降解的有机化合物，具有致癌、致畸、致变的潜在毒性，是炼油、炼焦、造纸、塑料、化工等工业废水中的主要污染物。传统的酚类化合物污水处理方法可行。随着环保技术的发展和对水体质量要求的提高，近20年来逐渐发展起来的多相光催化降解技术可以有效地降解难以降解的酚类化合物。光催化降解酚类废水是将酚类化合物全部矿化为CO₂、H₂O或毒性较小的有机物，达到无害处理的要求。该方法与其他废水处理方法比较，具有能耗低、降解较完全、工艺较简单等特点，在废水处理领域中具有巨大的应用前景。本论文研制了一种新型的光催化剂，该催化剂对光的响应范围较经典的TiO₂光催化剂宽，光催化降解性能好，是一种具有较好开发应用前景的光催化剂。 本文通过多种方法合成了一系列光催化剂，并对其催化活性进行比较分析，发现Bi₂O₃-V₂O₅和Bi₂O₃-Y₂O₃光催化剂具有较高的催化活性，并对催化剂制备的有关影响因素，如物料配比、焙烧温度及焙烧时间等进行了研究。采用固体漫反射紫外扫描（DRS）、X射线衍射（XRD）、综合热分析（TG-TDA、DSC）、傅立叶红外扫描（FT-IR）、正电子湮没（PLS）等现代分析手段对催化剂进行了表征，并关联其活性数据，得出催化剂 广西大学2001级硕士研究生毕业论文光催化降解2，4一二氯苯酚废水的Bi:03一vZo。和BiZ氏一YZ氏催化剂研究的催化性能与结构的关系。 研究表明，Bi203一V205催化剂在Bi203与V205氧化物配比为1:l、焙烧温度为850℃、焙烧时间为9h时，催化剂的活性最好，对二氯苯酚的降解率可达86.6%，比纯Bi203提高了1.1.0%。分析表明，Bi203一20。催化剂的禁带宽度为2.4eV，比Ti02的3.2 eV禁带宽度较窄。Bi203一Y203催化剂在Bi203和Y203氧化物配比为1:0.5、焙烧温度为8加℃、焙烧时间为9h，催化剂的活性最好，对二氯苯酚的降解率可达92.7%，比纯Bi203提高了17.1%，分析表明，该催化剂的禁带宽度为2.Zev。正电子湮没实验和傅立叶红外扫描得知，Bi203一v20。催化剂含有丰富的表面经基及氧空缺，并且由于催化剂的禁带宽度窄，所以在光照条件下，能产生较多的电子一空穴对，进行较多的光催化降解反应。 工艺条件研究表明，在光催化降解50mg/L的2，4一二氯酚废水时，Bi203一V20。最佳催化剂用量为0.3759/’L、最佳溶液pH值为6.0、最佳H202用量为50mL/L，二氯苯酚降解反应在低浓度时降解速率符合L一H动力学方程，而在高浓度时降解速率与初始浓度无关。更多还原

【Abstract】 The phenolic compound is an organic compound, which can hardly be degraded. It is a toxic material with latent possibility to cause cancer, abnormality, and aberrance as well. It is also an aquatic and main pollutant that exists in industrial wastewater coming from the oil refining, coke, deckle, plastics, chemical engineering etc. Various traditional methods of disposing of wastewater containing phenolic compound such as physics, chemistry, biological chemistry, do not function properly because of them shortcoming. Along with the development of the environmental protection technique and the improvement of demand for the quality of water, heterogeneous photocatalytic degradation technique gradually developing in the last twenty years can effectively degrade the phenolic compound that is not easy to dispose. Photocatalyticdegradation of the phenoic compound wastewater is a treatment that mineralize the phenoic compound into CO2, H2O or non-toxic organic compound thus achieves the demand for non-toxic process . Comparing with other disposition of wastewater, this method has the property such as energy conservation, much more complete degradation, simple technics, which shows a great perspective in the field of disposition of wastewater.The author develops a new type of photocatalyst, which has a wider responding value to the sunlight than the classic one--TiO2, and possesses good performance of photocatalytic degradation. This photocatalyst has nice applied perspective. This paper synthesizes a series of photocatalyst with various methods. Analyses and assessment of catalyst activity is carried out. It is found that both Bi2O3-V2O5 and Bi2O3-Y2O3 have higher activity than others. Various influencing factors in the process of preparing catalyst have been taken into consideration, for an instance, the ratio of materiel, baking temperature, baking time. The modern technology is used in the characterization of photocatalyst, for example, DRS, XRD, TG-TDA, DSC, FT- IR, and PLS as well. All the data gained in the experiment are related with the data from the assessment of catalyst act ivity, and finally the relationship of catalyst capacity with itsstructure is given out.The research shows, the Bi2O3-V2O5 catalyst has the best activity with the material(Bi2O3 and V2O5) ratio by 1:1, baking temperature by 850 C, baking time by 9h, the ratio of degradating 2,4-dichIorophenol reach by 86.6%, increase by 11.0% comparing to pure Bi2O3.The analysis found that the band gap of Bi2O3-V2O5 catalyst is 2.4 eV, and narrower than TiO2(3.2eV). The research shows ,the Bi2O3-Y2O3 catalyst has the best activity with the material (Bi2O3 and Y2O3) ratio by 1:0.5, baking temperature by 850 "C, baking time by 9h,the ratio of degradating 2,4-dichlorophenol reach by 92.7%, increase by 17.1% comparing to pure Bi2O3. The analysis found that the band gap of Bi2O3-Y2O3 catalyst is 2.2 eV. The surface of Bi2O3-V2O5 catalyst has hydroxyl and oxygen defects in abundances, which is supported by the PLS and FT-IR experiment. Catalyst under irradiation of mercury lamp can produce many electron-positive hole to favor the photocatalytic degradation reaction, since it has narrow band gap. It indicates in term of condition of technology that when photocatalytic reaction goes in the solution with 2,4-dichlorophenol wastewater concentration about 50mg/L, the best dose of catalyst is 0.375 g/L, pH 6.0 H2O2 50mL/L, the degradation rate accords with Langmuir-Hinshelwood kinetics at low concentration but irrelevant to original con-centration at high in 2,4-dichlorophenol degradation reaction.更多还原