ZnO及复合物的制备与光催化降解甲基橙染料的研究

发布时间：2018-06-28 18:48

本文选题：光催化剂 + 氧化锌　；参考：《昆明理工大学》2017年硕士论文

【摘要】：数十年来,水污染及其造成的相关影响是人类社会需要面临的重大难题。目前主要的水体污染源是工业废水,如钢铁冶金企业产生的焦化废水等。当前需要寻找一种运行费用低,去污能力强,不易产生二次污染并且能够广范围使用的工业废水处理技术。光催化技术作为一种高级氧化技术可以利用太阳光将有机污染物矿化为H_2O和CO_2,不会对环境造成二次危害。因此光催化技术是有良好应用前景的绿色水处理技术。在可用于光催化反应的半导体中,ZnO因具有优良的光电性质和安全无毒等优点使其在太阳能研究领域中备受关注。本论文研究内容包括:(1)采用水热法制备出五种形貌ZnO材料。所得ZnO材料均属纤锌矿型,结晶较好;通过紫外光下光催化降解甲基橙实验表明:五种形貌的ZnO材料的光降解反应均属类一级反应,其降解效率分别为:η针状=72.6%,η花瓣状=77.5%,η片层状=68.6%,η绒球状=84.4%和η球状=62.1%;催化材料比表面积越大,则降解效率更高;五种ZnO材料中除片层状外,材料结晶度与降解效率成正相关;反应环境中光催化剂用量与降解效率呈先增后平的关系,反应环境中有机物初始浓度和助氧化剂浓度与降解效率呈倒U型关系,反应环境中溶液pH值与降解效率呈U型关系。纯ZnO材料存在严重的光腐蚀其随反应进行会逐渐消耗且不易回收,因此纯ZnO光催化剂不适用于作光催化降解反复利用。(2)利用溶液混合法制备出不同质量掺杂比(Fe_3O_4@ZnO:GO)具有可见光响应的磁性复合光催化剂。在可见光下进行光降解甲基橙的实验表明:当Fe_3O_4@ZnO和GO的质量比率为0.8:0.2时,光催化性能最佳,在150min内降解效率η=92%;光催化反应主要发生在Fe_3O_4@ZnO表面,GO并不直接参与光催化反应;该磁性复合材料可通过施加外部磁场达到光催化剂的有效分离,并且可实现有限次循环使用。因此,这种增强了光电化学性能的磁性复合光催化剂可以成为去除废水中有机物的候选材料。
[Abstract]:For decades, water pollution and its related impacts have been a major problem for human society. At present, the main source of water pollution is industrial wastewater, such as coking wastewater produced by iron and steel metallurgical enterprises. At present, it is necessary to find a kind of industrial wastewater treatment technology with low operating cost, strong decontamination ability, not easy to produce secondary pollution and can be widely used. As an advanced oxidation technology, photocatalytic technology can mineralize organic pollutants into H _ 2O and CO _ 2 by solar light, which will not cause secondary harm to the environment. Therefore, photocatalytic technology is a promising green water treatment technology. ZnO has attracted much attention in the field of solar energy research because of its excellent photoelectric properties and safety and non-toxicity in photocatalytic semiconductor. The main contents of this thesis are as follows: (1) five ZnO materials with different morphologies were prepared by hydrothermal method. The results of photocatalytic degradation of methyl orange under ultraviolet light showed that the photodegradation reaction of all the ZnO materials with five morphologies was of a class 1 order reaction, and all of the ZnO materials were of wurtzite type and had good crystallinity, and the photocatalytic degradation of methyl orange was characterized by photocatalytic degradation of methyl orange. The degradation efficiencies were: 畏 acicular 72.6, 畏 petal 77.5, 畏 lamellar 68.6, 畏 villous 84.4% and 畏 spherical 62.1; the larger the specific surface area of the catalytic materials, the higher the degradation efficiency, the higher the crystallinity of the five ZnO materials except the lamellar layer, the higher the crystallinity and the degradation efficiency, the higher the degradation efficiency was, the higher the specific surface area of the catalytic materials was, the higher the degradation efficiency was, and the higher the degradation efficiency was, the higher the specific surface area of the catalytic materials was, the higher the degradation efficiency was. In the reaction environment, the amount of photocatalyst increased first and then the degradation efficiency, the initial concentration of organic matter and the concentration of co-oxidant in the reaction environment were inversely U-shaped, and the pH value of the solution in the reaction environment was U-shaped with the degradation efficiency. The pure ZnO material has serious photocorrosion which will be consumed gradually with the reaction and is not easy to be recovered. Therefore, pure ZnO photocatalyst is not suitable for repeated use of photocatalytic degradation. (2) the magnetic composite photocatalyst with different mass doping ratio (Fe3O4 / ZnO: go) has visible light response. The experiment of photodegradation of methyl orange under visible light shows that when the mass ratio of Fe3O4ZnO and go is 0.8: 0.2, the photocatalytic performance is the best, and the degradation efficiency 畏 ~ (92x) in 150min is the best, and the photocatalytic reaction mainly occurs in Fe3O4 / ZnO surface and go does not directly participate in the photocatalytic reaction. The magnetic composite can be separated effectively by external magnetic field and can be reused for a limited time. Therefore, the magnetic composite photocatalyst, which enhances the photochemical properties, can be used as a candidate material for the removal of organic compounds in wastewater.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;X703

【参考文献】