论文总字数：28506字

摘 要

甲醛是一种易致癌的气体污染物。若在空气中的浓度超过某一值，可能会严重地危害人类的生命安全，因此，有效去除室内空气中的甲醛意义重大。催化氧化法是脱除甲醛很有效的方法。研究表明，催化氧化技术可将甲醛转化为CO₂和H₂O，操作简便、效率高，具有广阔的发展前景和实际应用的潜力，设计和研究室温高活性、高稳定性的催化剂是研究者们普遍追求的目标，通过合适的固体载体或者有效改性催化剂等手段以提高催化剂催化效率。本研究较为常用的载体入手，主要进行了以下的研究工作：

首先，在文献整理分析的基础之上，我们对去除甲醛催化剂的背景、应用、以及主要的制备方法等进行了介绍。然后，以普遍使用的氧化钛、氧化铝作为载体，采用浸渍法制备出了Pt/P25、Pt/Al₂O₃催化剂，并通过添加碱金属助剂(Na)对其表面进行了修饰改性。研究中，考查了贵金属、碱金属的掺入对纳米催化剂的理化特性，包括结晶性、微观特征结构（孔结构等）的影响，同时着重考查其在干燥环境气氛下对甲醛的吸附-催化反应性能。实验结果显示：1) Pt和碱金属的添加，未引起载体氧化钛、氧化铝载体的相变，在干燥气氛环境下氧化铝载体负载型催化剂催化氧化性能优于氧化钛 2) 碱金属的添入，改变了氧化钛粉体的比表面积，其催化甲醛效果随掺杂量的上升而提升；

此外，由于室内环境中有水蒸气的存在，因此从实际应用角度考虑，探索不同含量水蒸气对催化剂催化氧化甲醛性能的影响是很有必要的。实验结果表明，①向催化剂体系中添加不同的碱金属前驱体钠盐对催化效果有着明显的影响，且添加硝酸钠和碳酸钠时促进作用最为明显。②反应系统中的水蒸气不仅可促进含钠催化剂的催化性能，还可显著地提高其催化氧化的稳定性。

关键词：载体 浸渍法 碱金属掺杂 催化氧化

Application of supported catalyst in catalytic oxidation of formaldehyde at room temperature

Abstract

Formaldehyde is a kind of pollutant gas which is easy to cause cancer. it may seriously endanger human life if its concentration is above a Standard value in the air, So, efficiently  removal  of formaldehyde is great significant at room temperature. Catalytic oxidation is a very useful method in removing formaldehyde. Studies have shown that the catalytic oxidation technology can translate formaldehyde into non-toxic CO₂ and H₂O, with its advantages of Operability, high degradation efficiency， therefore, it has a broad development prospect and wide application foreground, also, It is a shared goal of researchers to design and find  environmentally  friendly  catalyts with high oxidation activity at room temperature, Recently the researchers  promote catalyst efficiency by methods of catalyst supports selection or appropriate  modification on the supports surfaces. Integrated above, the commonly supports are studied in the following research work, In detail, the research content of this paper chiefly include:

Based on the analysis of the previous literature, the background ,application ,the catalyst preparation methods for formaldehyde removed are firstly introduced. owing to some supports (such as titanium oxide of P25, alumina ) are been widespread used in the papers, Then, Pt/Al₂O₃、 Pt/P25 catalysts are prepared by impregnation method and carriers surfaces modificated by adding alkali additives (Na) to explore the incorporation of precious metals, alkali metal with the physical and chemical properties of nano catalyst (including crystalline, microscopic characteristics of the structure, pore structure, etc), and the formaldehyde adsorption-catalysis performance  is  further investigated in the dry atmosphere. Experimental results show that: 1) The addition of the Pt and alkali did not cause the phase transition of titanium oxide, alumina carriers, and Alumina-supported  Catalysts for catalytic oxidation performance is better than that of titanium oxide in the non-aqueous environment. 2) The addition of alkali metal, has changed the specific surface area of the titanium oxide or alumina, and the catalytic activity  increased with the ascend sodium-doping amount;

In addition, during to the presence of water vapor in the indoor environment, So, Studying on how the different content of water vapor influence the performance for catalytic oxidation of formaldehyde is very necessary from a practical point of view. The results show that: (1) Adding  different alkali metal salt precursor sodium component in the catalyst system, have effected on catalytic degration efficiency, and sodium nitrate and sodium carbonate are most obvious in promoting catalytic performance. (2) The existence of Water vapor in the reaction condition not only can enhance the catalytic degration activity of sodium-added catalyst, also remarkably improve the catalytic oxidation stability.

Key words: Supports; Impregnation method; Alkali metal; Catalytic oxidation

目 录

摘要 Ⅰ

Abstract ..Ⅱ

第一章 文献综述 1

1.1甲醛的来源、危害及净化方法 1

1.1.1 甲醛的来源和危害 1

1.1.2 甲醛治理技术简介 2

1.2催化氧化简介 3

1.2.1 催化剂体系 4

1.3 催化剂的制备方法 6

1.3.1 浸渍法 6

1.3.2 等离子体技术 7

1.3.3 沉淀法 7

1.3.4 微波和超声辅助法 8

1.4 实验内容和任务 8

第二章 实验部分 10

2.1 实验原料与设备 10

2.2 催化剂制备 10

2.3 催化剂表征 11

2.4 室温催化氧化甲醛 11

第三章 Pt-TiO₂在甲醛氧化反应中的催化活性研究 13

3.1 干燥气氛中制备条件对催化剂活性的影响 13

3.1.1 Na含量对催化剂活性的影响 13

3.2 反应气中添加水蒸气对Pt -xNa - TiO₂催化剂活性和稳定性的影响 15

3.2.1 添加水蒸气对甲醛氧化稳定性的影响 15

3.3 小结 17

第四章 Pt-Al₂O₃在甲醛氧化反应中的催化活性研究 18

4.1 干燥气氛中制备条件对催化剂活性的影响 18

4.1.1 Na含量对催化剂活性的影响 19

4.2 反应气中添加水蒸气对Al₂O₃-Pt -xNa催化剂活性和稳定性的影响 20

4.2.1 水蒸气对不同Na前驱体制得的催化剂活性的影响 24

4.2.2 制备方法对Al₂O₃-Pt -xNa制得的催化剂活性的影响 26

4.2.3 添加水蒸气对Al₂O₃-Pt -xNa甲醛氧化稳定性的影响 27

4.3 小结 24

第五章 结果与展望 25

5.1 结论 25

5.2 展望 25

参考文献 29

致谢 31

第一章 文献综述

1.1甲醛的来源、危害及净化方法

1.1.1 甲醛的来源和危害

请支付后下载全文，论文总字数：28506字