二氧化钛纳米材料的制备、改性及光催化性能研究

发布时间：2018-02-19 19:25

  本文关键词： 溶胶-溶剂热法 二氧化钛 改性 光催化 甲基橙　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着人们生活水平的不断提高,越来越多的产品来自于石油、煤炭和天然气等不可再生的自然资源。同时,产品在原材料的提取、运输和转化过程中都有可能给环境带来负面效应。因此,环境污染和能源短缺现象成为人类目前应对的世界性难题。半导体光催化技术在环境修复领域的作为不容忽视,已被证明是降解水体和大气环境中有害污染物的有效途径。在解决能源危机方面,通过光分解水制氢、太阳能电池等方式实现了可再生能源的高效利用。二氧化钛因其高稳定性,无毒性且低成本被认为是非常理想的光催化半导体材料。光催化剂的表面积是决定污染物吸附量的重要因素,直接影响其光催化活性的强弱。由于二氧化钛纳米材料的高表面能使得纳米粒子间倾向于聚集以达到体系的平衡状态,导致纳米粉体的团聚现象严重,无法获得较大的活性表面积。因此,本文采用表面活性剂作为分散剂,并优化制备工艺进行改性,以获得均一分散的二氧化钛纳米体系是十分必要的。主要研究内容如下:(1)综合溶胶-凝胶法和溶剂热法的制备优势,本论文采用溶胶-溶剂热改进工艺进行实验分析。以钛酸丁酯为钛源,无水乙醇为溶剂,浓硝酸为抑制剂,按照n(Ti(OR)4):n(C2H5OH):n(H+):n(H2O)=1:15:0.35:4的反应物配比,制备纳米级二氧化钛材料。(2)通过单因素实验与正交实验相结合的方式,以样品对甲基橙的光催化降解率为分析依据,探究溶剂热温度、溶剂热时间、煅烧温度和煅烧时间对于二氧化钛光催化活性的影响。正交实验的结果表明,最佳工艺参数是:当溶剂热温度为150℃,溶剂热时间为24h,煅烧温度为450℃,煅烧时间为4h时,样品的光催化降解率最高,为82.88%。同时XRD、SEM、TEM和EDS的图像表明,样品为结晶度良好的单一锐钛矿相,无任何杂质,但分散性一般。(3)在最佳工艺参数的基础上,通过控制表面活性剂的种类和含量的不同,探究不同类型表面活性剂的最佳投料比,从而确定用于二氧化钛纳米粉体改性的最佳分散剂,并通过XRD、SEM、TEM和EDS等技术对样品进行表征。实验结果表明,不同类型表面活性剂的最佳投料比(与钛酸丁酯的质量比)分别是:阳离子表面活性剂CTAB为1:60、阴离子表面活性剂SDBS为1:30、非离子型表面活性剂PEG为1:30。不同类型表面活性剂在最佳投料比条件下,CTAB改性纳米二氧化钛、SDBS改性纳米二氧化钛、PEG改性纳米二氧化钛相比于未改性纳米TiO_2的光催化降解率分别提高了16.28%、13.41%、9.23%。样品均为纯净的、结晶度较好的单一锐钛矿相,且CTAB的改性效果明显好于SDBS和PEG,得到的纳米粒子均一分散。
[Abstract]:As people's living standards continue to improve, more and more products come from non-renewable natural resources such as oil, coal and natural gas. At the same time, the products are extracted from raw materials. Therefore, environmental pollution and energy shortage have become a worldwide problem for mankind to deal with. Semiconductor photocatalytic technology can not be ignored in the field of environmental remediation. Has proven to be an effective way to degrade harmful pollutants in water and the atmospheric environment. In resolving the energy crisis, hydrogen is produced by photodecomposition of water, Solar cells and other ways to achieve the efficient use of renewable energy. Titanium dioxide because of its high stability, Non-toxic and low-cost photocatalytic semiconductor materials are considered ideal. The surface area of photocatalysts is an important factor in determining the adsorption capacity of pollutants. Because of the high surface energy of TIO _ 2 nanoparticles tend to aggregate in order to achieve the equilibrium state of the system, which leads to the serious agglomeration of nano-powders. Therefore, the surfactant was used as dispersant and the preparation process was optimized. It is necessary to obtain homogeneous and dispersed TIO _ 2 nanosystems. The main research contents are as follows: 1) Synthesis advantages of sol-gel method and solvothermal method. In this paper, the sol-sol-thermal process was used to improve the experimental results. Using butyl titanate as titanium source, anhydrous ethanol as solvent, and concentrated nitric acid as inhibitor, the ratio of reactants of 1 15: 0. 35: 4 was determined according to the ratio of the reactants of nTiorao 4: C _ 2H _ 5OH _ 1: h _ 2O _ 1: 1 15: 0.35: 4. The preparation of nanometer titanium dioxide material. 2) through the combination of single factor experiment and orthogonal experiment, based on the photocatalytic degradation rate of methyl orange, the solvothermal temperature and solvothermal time were studied. Effects of calcination temperature and calcination time on the photocatalytic activity of titanium dioxide. The results of orthogonal experiment show that the optimum technological parameters are as follows: the solvothermal temperature is 150 鈩，

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