Ⅱ-Ⅵ族量子点的负载及其光催化性能的研究

发布时间：2018-03-02 05:22

  本文关键词： 复合材料 硫化镉 碲化镉 水相合成 多空材料 光催化降解　出处：《广西大学》2015年硕士论文　论文类型：学位论文

【摘要】：论文首先简要的论证了光催化降解染料废水的优异性,总结了水处理的一些传统方法,通过比较,讨论了TiO2、CdS、CdTe等半导体光催化剂的优缺点。概括论述了光催化降解染料废水的研究进展和现状,系统的总结了光催化剂的光催化机理,导体光催化材料的结构,并且进一步论述了影响光催化降解过程的因素。总结了在各个领域应用范围很广的CdS和CdTe量子点的制备方法,并且水相合成了CdS和CdTe与沸石(或膨润土)的复合物,初步探究了其光催化应用条件,初步建立论文研究方案。具体实验如下：第一、以CdCl2·2.5H2O, SeO2和NaBH4为反应物,制备巯基丁二酸稳定的CdSe量子点。然后将有机膨润土与CdSe量子点溶液混合并充分搅拌,制备负载CdSe量子点的膨润土发光材料,用荧光光谱、扫描电镜和X射线粉末衍射等分析测试手段对所得材料的光谱性能与微观结构进行表征。光谱分析表明,量子点膨润土复合材料的发光颜色与量子点溶液非常一致；X射线光电子能谱分析表明,复合后的材料中含有Cd和Se两种元素；此外,量子点膨润土复合材料X射线粉末衍射谱中可见CdSe量子点(111), (220)及(331)三个晶面的衍射峰, 在20=4.3°处出现膨润土(001)衍射峰。数据表明,制备CdSe量子点膨润土复合材料,没有改变量子点和膨润土的结构；第二,以CdCl2和硫代乙酰胺为反应物,通过湿化学法合成CdS/膨润土复合材料,采用X射线衍射(XRD)、红外光谱(FTIR)以及紫外可见光谱(UV-Vis)等分析技术对其结构及光学性能进行表征。以罗丹明B和亚甲基蓝为目标污染物,考察了CdS/膨润土复合材料对有机染料的降解性能。结果表明：在罗丹明B和亚甲基蓝的初始浓度为20mg/L时,光照3h后,CdS/膨润土对它们的降解率分别为80.6%和88.3%,优于CdS及膨润土原土催化剂；第三、以巯基乙酸为稳定剂、硫代乙酰胺为硫源合成CdS量子点并将其负载与沸石中。研究了复合材料的光学特性,通过XRD. UV-Vis.分子荧光对其进行了表征。以氙灯为光源,降解甲基橙、结晶紫和茜素红三种染料以探究复合材料的光催化性能。结果表明,经过一定时间的光照反映后,复合材料对三种染料的降解率为结晶紫93.62%、茜素红80.95%、甲基橙86.36%；第四、以CdCl2和Na2TeO3为反应物,抗坏血酸为还原剂,通过湿化学法合成CdTe量子点/膨润土复合材料。采用X射线衍射、荧光光谱及紫外可见光谱等分析技术对其结构及光学性能进行表征。以汞灯为光源,甲基橙为目标污染物,研究了CdTe/膨润土复合材料的光催化活性。实验表明：在甲基橙溶液初始浓度为1 Omg/L时,经汞灯光照反应60min后,CdTe/膨润土因光催化反应对甲基橙的降解率为66.23%,优于CdTe量子点光催化剂。
[Abstract]:Firstly, the paper briefly demonstrates the excellence of photocatalytic degradation of dye wastewater, summarizes some traditional methods of water treatment, and compares them with each other. The advantages and disadvantages of semiconductor photocatalysts such as TIO _ 2O _ 2 ~ (2 +) CdS- CdTe are discussed. The research progress and present situation of photocatalytic degradation of dye wastewater are summarized. The photocatalytic mechanism of photocatalyst and the structure of conducting photocatalytic materials are systematically summarized. The preparation methods of CdS and CdTe quantum dots, which are widely used in various fields, were summarized, and the complexes of CdS and CdTe with zeolite (or bentonite) were synthesized in aqueous phase. The application conditions of photocatalysis were preliminarily explored, and the research scheme was established. The experiments were as follows: firstly, CdCl2 路2.5H _ 2O, SeO2 and NaBH4 were used as reactants. The stable CdSe quantum dots with mercaptosuccinic acid were prepared, and then the organic bentonite and CdSe quantum dots were mixed and stirred sufficiently to prepare the bentonite luminescent materials loaded with CdSe quantum dots. The spectroscopic properties and microstructure of the obtained materials were characterized by SEM and X-ray powder diffraction. The luminescence color of the bentonite composite is very consistent with that of quantum dot solution. The X-ray photoelectron spectroscopy analysis shows that the composite material contains two elements, CD and se. In the X-ray powder diffraction spectrum of quantum dot bentonite composites, the diffraction peaks of CdSe quantum dots 111U, 220and 331are observed, and the diffraction peaks of bentonite are observed at 204.3 掳. The data show that the CdSe quantum dot bentonite composites have been prepared. The structure of quantum dots and bentonite was not changed. Secondly, CDs / bentonite composites were synthesized by wet chemical method using CdCl2 and thioacetamide as reactants. The structure and optical properties of Rhodamine B and methylene blue were characterized by X-ray diffraction, FTIR and UV-Vis. etc. The degradation of organic dyes by CDs / bentonite composites was investigated. The results showed that the initial concentration of Rhodamine B and methylene blue was 20 mg / L, The degradation rates of CDS / bentonite were 80.6% and 88.3 respectively after 3 h irradiation, which were superior to those of CdS and bentonite catalysts. Third, thioglycolic acid was used as stabilizer, and thioglycolic acid was used as stabilizer. CdS quantum dots were synthesized by thioacetamide as sulfur source and loaded into zeolites. The optical properties of the composites were studied and characterized by XRD. UV-Vis.Molecular fluorescence. Using xenon lamp as light source, methyl orange was degraded. Crystal violet and alizarin red dyes were used to study the photocatalytic properties of the composite. The results showed that the degradation rates of the composite were 93.622% crystal violet, 80.95% alizarin red, 86.36 methyl orange, 4th, 4th, respectively, after a certain period of light reaction, the degradation rates of the three dyes were as follows: Crystal violet 93.62 2, alizarin red 80.95, methyl orange 86.36; CdTe quantum dots / bentonite composites were synthesized by wet chemical method using CdCl2 and Na2TeO3 as reactants and ascorbic acid as reducing agent. The structure and optical properties were characterized by fluorescence spectra and UV-Vis spectra. The mercury lamp was used as the light source and methyl orange as the target pollutant. The photocatalytic activity of CdTe / bentonite composite was studied. The experimental results show that when the initial concentration of methyl orange solution is 1 Omg/L, The degradation rate of methyl orange by photocatalytic reaction of CdTe / bentonite was 66.23%, which was superior to that of CdTe quantum dot photocatalyst.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;O643.3

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