负载型光催化剂的设计及其降解有机污染物的研究

发布时间：2018-06-02 19:32

本文选题：BiOBr_xI_(1-x)可见光催化薄膜 + 荧光转盘反应器　；参考：《上海师范大学》2017年硕士论文

【摘要】：随着全球对于环境问题的日益关注,光催化技术用于处理环境中的污染物的优势亦被全球研究者广泛关注。为了提高光催化活性和对太阳光的利用率,研究者开发了众多光催化剂,如粉末和薄膜催化剂。铋基复合氧化物具有独特的层状结构,有利于光捕获和光生载流子的传递,提高光催化活性,且能通过层间分子或者离子变化调变催化剂光催化性能,因此一直都是光催化材料领域研究的热点。其中,BiOBr光催化剂因其在可见光下具有较高的活性和稳定性,近年来基于BiOBr所进行的催化剂改进和探索研究逐渐成为热点。目前,研究者已经开发了不同方法制备光催化剂,如:水解法、反相微乳液法、溶剂热法和微波法等,并且可以得到不同形貌的光催化剂,如花球状、纳米粒子等。然而,对以BiOBr为母体的光催化剂仍需进行相关研究,以在未来实际污染物治理中发挥作用。目前存在的问题主要包括:(1)研究工作主要集中在粉体催化剂,存在分离困难且难以重复利用的缺陷,(2)有色染料对光的屏蔽作用,使得催化剂吸收光的效率大幅下降,(3)光催化过程仅能在有光的条件下进行,夜间难以持续进行光催化反应针对以上问题,本论文主要开展了以下工作:(1)离子液体辅助溶剂热法制备BiOBr_xI_(1-x)光催化薄膜及其在转盘反应器上的应用实验制备了负载型的BiOBr_xI_(1-x)光催化薄膜,解决了粉体催化剂难以回收利用和二次污染的问题。荧光转盘反应器的设计即降低了有色染料对光的屏蔽,同时与催化剂的匹配实现了全天候光催化。具体实验过程中,优化了催化剂的釜热制备条件,并根据催化剂的光吸收范围与荧光粉的发光范围优化催化剂中Br与I的比例。咪唑溴盐离子液体([C16mim]Br)和咪唑碘盐离子液体([C6mim]I)在膜生长过程中既作为溴源也作为结构导向剂,得到了交织网状并长于玻璃基底上的膜催化剂。用X射线粉末衍射(XRD)、扫描电镜(FESEM)研究其晶体结构和形貌特征,用紫外可见分光光度计(UV-Vis Diffuse Reflectance Spectrum)研究Br与I不同比例的样品的光吸收范围,并用荧光光谱研究所选择的转盘中荧光粉的发光范围,二者相互匹配的结果确定了最终的光催化剂,该实验中以降解罗丹明B(RhB)作为探针反应研究其光催化性能。(2)漂浮型BiOBr-GO-MF光催化剂及其降解RhB的性能研究光催化剂负载在较轻的GO修饰的密胺树脂基底上,使得催化剂便于回收和重复利用。催化剂漂浮在有色污染物溶液上方,减少溶液的光屏蔽作用,尤其降解高浓度的有色污染物时,漂浮型催化剂展现较高的光催化活性。具体实验过程中,首先通过浸渍烘干的方法在密胺树脂上负载一定量的GO,再通过溶剂热的方法负载上一定量的BiOBr。实验中针对催化剂漂浮在不同浓度的RhB溶液中不同深度处的吸附性能和光催化活性分别做了研究,结果表明催化剂在溶液中不同深度处的光催化降解活性差异主要是由光催化剂在不同深度时其正面对污染物的吸附能力和RhB溶液对光的屏蔽作用造成的。
[Abstract]:With the increasing attention of the world to environmental problems, the advantages of photocatalytic technology in the treatment of pollutants in the environment have also been widely concerned by researchers around the world. In order to improve the photocatalytic activity and the utilization of sunlight, researchers have developed a number of photocatalysts, such as powder and film catalysts. Bismuth based composite oxides have unique layers. The structure, which is beneficial to the transmission of optical capture and photogenerated carrier, improves the photocatalytic activity, and can modulate the photocatalytic activity of the catalyst through the change of interlayer molecules or ions. Therefore, it has always been a hot spot in the field of photocatalytic materials. Among them, BiOBr photocatalyst has high activity and stability under visible light. In recent years, the photocatalyst is based on Bi. The catalyst improvement and exploration of OBr has gradually become a hot spot. At present, researchers have developed different methods to prepare photocatalyst, such as hydrolysis, reverse microemulsion, solvent thermal and microwave, and can obtain different morphologies of photocatalyst, such as flower ball, nanoparticles, etc., however, the light of BiOBr is the mother of the matrix. Chemical agents still need to be studied in order to play a role in the future treatment of actual pollutants. The main problems are as follows: (1) the research work is mainly concentrated on the powder catalyst, which is difficult to be separated and difficult to reuse, (2) the shielding effect of colored dyes on light, which makes the efficiency of the absorption light of the catalyst drop significantly, (3) light. The catalytic process can only be carried out under light conditions, and it is difficult to continue photocatalytic reaction at night for the above problems. The following work has been carried out in this paper: (1) BiOBr_xI_ (1-x) photocatalytic film is prepared by ionic liquid assisted solvent thermal method and its application on a turntable reactor to prepare supported BiOBr_xI_ (1-x) photocatalytic thinning The membrane has solved the problem that the powder catalyst is difficult to recycle and two pollution. The design of the fluorescent disc reactor is designed to reduce the shielding of the colored dye to the light. At the same time, the all-weather photocatalysis is realized with the matching of the catalyst. In the specific experiment, the conditions of the preparation of the catalyst are optimized and the light absorption range of the catalyst is based on the range of the photocatalyst. The luminescence range of the phosphor is optimized for the ratio of Br to I. Imidazolium bromide ionic liquid ([C16mim]Br) and imidazole iodized ionic liquid ([C6mim]I) are used both as the bromine source and as the structural guide in the membrane growth, and the interwoven network and the membrane catalyst on the glass substrate are obtained. X ray powder diffraction (XRD) and scanning electron microscopy (FESEM) are used. In order to study the crystal structure and morphologies, UV-Vis Diffuse Reflectance Spectrum (UV-Vis Reflectance Spectrum) was used to study the light absorption range of the samples with different proportions of Br and I, and the luminescence range of the phosphor in the selected turntable was studied by the fluorescence spectrum. The final photocatalyst was determined by the results of the two matching. Study on the photocatalytic properties of Luo Danming B (RhB) as a probe. (2) the performance of floating BiOBr-GO-MF photocatalyst and its degradation of RhB, the photocatalyst was loaded on the lighter GO modified melamine resin substrate, making the catalyst easier to recover and reuse. When the light shielding effect, especially the high concentration of colored pollutants, the floating catalyst exhibits high photocatalytic activity. In the specific experiment, a certain amount of GO is loaded on the melamine resin by the impregnation drying method, and then a certain amount of BiOBr. experiments on the load by solvent heat are used to float the catalyst in different concentration. The adsorption and photocatalytic activity at different depths in the RhB solution were studied. The results showed that the photocatalytic degradation activity of the catalyst at different depths in the solution was mainly caused by the adsorption capacity of the photocatalyst at different depths and the shielding effect of the RhB solution on the light.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X505;O643.36

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