无机微介观复合孔材料的合成与表征

发布时间：2018-05-27 11:43

本文选题：介孔材料 + 微介孔复合材料　；参考：《吉林大学》2015年博士论文

【摘要】：微介孔复合材料是研究人员期待的理想孔材料。但是如何能够将沸石具有介孔结构而又不牺牲掉沸石本身具有的高稳定性和催化活性是我们面临的一大难题。目前多级孔分子筛材料的研究主要集中在硅铝酸盐材料方面，而多级孔磷酸铝、磷酸硅铝材料的报道很少，我们选择合成微介孔复合材料的磷酸铝、磷酸硅铝催化材料在材料的合成和制备领域属于应用基础研究的前沿，对其酸活性和稳定性的增加其进行探索。本文成功利用导向剂法，将沸石分子筛的导向剂MFI，β，Y和L的次级结构单元在碱性条件下与十六烷基三甲基氯化铵表面活性剂相互作用，分别制备了高度有序的微介孔复合磷酸铝材料SAPOS （Al-JQW-5，Al-JQW-6，Al-JQW-7和Al-JQW-8）。与传统介孔SAPO材料相比，多级孔Al-JQW的孔壁较厚。而且介孔骨架缩合程度好，所以综上两点该介孔材料具有较高的热稳定性。而且随着导向剂引入多级孔Al-JQW具有弱酸和强酸两种的酸活性中心且酸性较强，另外从各种沸石前体组装各种Al-JQW样品的酸度是不同的。酸性强度的顺序如下：Al-JQW-5Al-JQW-6的Al-JQW-7的Al-JQW-8，其结果与异丙基苯的催化实验中的转化率相同，而且与以前研究中得知的沸石的酸性顺序相一致，如下：MFI BEA Y L。第二部分实验，我们使用微孔SAPO-5导向剂为无机物种使用十六烷基三甲基氯化胺（CTAC）作为模板剂，利用超声波进行预处理，，水热条件下成功地将SAPO-5分子筛纳米晶嵌入了高度有序的介孔孔壁内，合成了微介孔复合硅磷酸铝分子筛SAPO-5-UW，结果表明以三乙胺和CTAC为双模板可以合成出微介孔复合分子筛SAPO-5-UW，透射电镜（TEM）照片显示产物具非常高的有序度，由于增厚的孔壁使其稳定性较好且产物具有中强酸中心和弱酸中心，在酸催化方面有潜在的应用价值。合成中超声波的辅助作用大大提高介孔相的生成速度，很好地实现了反应物之间的均匀混合，促进固体新相的形成，是一种非常方便快捷，并且适合广泛应用于纳米材料的合成辅助手法。我们在合成步骤中改变通过超声辅助的顺序，将表面活性剂事先在超声环境下溶解，再加入导向剂，进一步水热晶化后所得到的是孔径在15-20纳米具有SAPO-5单晶孔壁的囊泡。这是非常理想的多级孔材料，可是遗憾的是材料中有一部分是无定型非孔磷酸铝材料。当前，中国的生态环境已经严重受到化学物质的污染，常年的水污染与大气雾霾直接影响了人体健康。环境污染控制与修复是环境化学领域当务之急的重大问题，在前两章的孔材料合成当中，本文作者发现，需要消耗很多的无机原料才能够合成复合孔材料，而且一般的微介孔复合材料的有序的和热稳定性都不是特别理想。因此，作者认为如何突破传统方法和技术以制备微孔，介孔以及复合孔材料和提高反应产率是目前合成研究中的一个极富探索意义的科学问题。于是作者第三部分实验致力于寻找到一个廉价的天然主体框架，可以将少量的沸石的次级结构单元进驻到主体框架内再进一步晶化，从而得到有序的超高稳定性的微介孔复合材料，作者发现很多种天然矿石适合这个想法，比如膨润土，云母等等，本着环保节约的想法，以工业的钠基膨润土为介观主体框架，只应用少量微孔沸石的导向剂就创新性地成功合成了高热稳定性的酸活性的微介孔复合有序介孔材料，AMC-ZSM-5，AMC-Beta和AMC-TEOS。经过测试我们新合成的材料具有非常高的热稳定性，这主要原因来源于其稳定的膨润土框架作为了孔道的上下孔壁，还有一部分原因是由于导向剂的加入使其左右孔壁也部分晶化。而且导向剂的加入使新材料具有微孔性，和其相对应的沸石的酸性。更重要的是使用的化学无机原料很少，属于绿色合成化学，而且膨润土一般更多的应用在污水处理方面，所以我们合成的微介孔复合有序介孔材料AMC-ZSM-5，AMC-Beta从制备到应用都是环境用好的新材料。
[Abstract]:Micro mesoporous composite is an ideal porous material expected by researchers. However, how to make zeolite have mesoporous structure without sacrificing the high stability and catalytic activity of zeolite itself is a difficult problem for us. At present, the research of multistage porous molecular sieves is mainly concentrated on the aluminosilicate material and multistage Kong Lin. Aluminum phosphate, aluminosilicate phosphate materials are rarely reported. We choose to synthesize aluminum phosphate of micro mesoporous composite. The synthesis and preparation of silicon and aluminum phosphate is the frontier of application basic research, and the increase of its acid activity and stability is explored.
In this paper, a highly ordered micro mesoporous aluminum phosphate composite SAPOS (Al-JQW-5, Al-JQW-6, Al-JQW-7 and Al-JQW-8) was prepared by interacting with the secondary structural units of zeolite molecular sieves MFI, beta, Y and L with sixteen alkyl three methyl ammonium chloride surfactants in alkaline conditions. Compared with the material, the multilevel hole Al-JQW has a thicker hole wall, and the mesoporous skeleton is well condensed, so the mesoporous material has high thermal stability. And with the introduction of the multi-stage hole, the Al-JQW has two acid active centers with weak acid and strong acid, and the acid is stronger. In addition, a variety of Al-JQW samples are assembled from various kinds of zeolite precursors. The order of the degree of acid is different. The order of the acid strength is as follows: Al-JQW-8 of Al-JQW-7 of Al-JQW-5Al-JQW-6, the result is the same as that in the catalytic experiment of isopropyl benzene, and it is in accordance with the acid order of the zeolite known in the previous study, as follows: MFI BEA Y L.
In the second part, we use the microporous SAPO-5 guiding agent for inorganic species to use sixteen alkyl three methyl chloramines (CTAC) as templates and pretreat them by ultrasonic wave. The SAPO-5 molecular sieve nanocrystals are successfully embedded in the highly ordered mesoporous wall under hydrothermal conditions, and the micro mesoporous compound silicon phosphate aluminum molecular sieve SAPO-5- is synthesized. UW, the results show that the micro mesoporous composite molecular sieve SAPO-5-UW can be synthesized with three ethylamine and CTAC as a double template. The transmission electron microscope (TEM) photo shows that the product has very high order degree. Because of the thickened hole wall, it has good stability and the product has middle and strong acid center and weak acid center. It has potential application value in acid catalysis. The auxiliary effect of sound waves greatly improves the formation speed of mesoporous phase, realizes the uniform mixing between reactants, and promotes the formation of new solid phase. It is a very convenient and quick method to be used in the synthesis of nano materials. In the synthetic procedure, we change the order of ultrasonic aid to the surface activity. The agent was dissolved in the ultrasonic environment and added to the guiding agent. After the hydrothermal crystallization, the pore size of the pore wall of the SAPO-5 single crystal hole was obtained at 15-20 nanometers. This is a very ideal multistage pore material. Unfortunately, some of the materials are amorphous and nonporous aluminum phosphate.
At present, the ecological environment of China has been seriously polluted by chemical substances. The annual water pollution and haze haze directly affect human health. The control and repair of environmental pollution is a major problem in the field of environmental chemistry. In the first two chapters, the author found that a lot of inorganic materials need to be consumed. The composite porous materials can be synthesized, and the ordered and thermal stability of the ordinary mesoporous composites are not particularly ideal. Therefore, the author believes that how to break through traditional methods and techniques to prepare micropores, mesoporous and compound porous materials and increase the yield of the reaction is a very important scientific problem in the recent research.
The third part of the author's experiment is to find a cheap natural body frame, which can further crystallize a small number of secondary structure units of zeolite into the main frame to obtain ordered ultra-high stability micro mesoporous composites. The author finds that many kinds of natural ores are suitable for this idea, such as bentonite, Mica and so on, in accordance with the idea of environmental conservation, using the industrial sodium bentonite as the mesoscopic frame, only a small amount of microporous zeolite guide is used to successfully synthesize the acid active microporous composite ordered mesoporous materials with high thermal stability. AMC-ZSM-5, AMC-Beta and AMC-TEOS. have been tested for our newly synthesized materials. The main reason for the high thermal stability is that the stable bentonite frame is used as the upper and lower hole wall of the channel, and partly because of the addition of the guide agent to crystallize the wall of the left and right holes. Moreover, the addition of the guide agent makes the new material microporous, and the acidity of the corresponding zeolite. Inorganic materials are rare, green synthetic chemistry, and bentonite is generally more used in sewage treatment, so our synthetic mesoporous composite ordered mesoporous material AMC-ZSM-5, AMC-Beta from preparation to application are good new materials for environmental use.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB33

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