自支撑ZSM-5分子筛和ZIF-8复合物球的合成与表征

发布时间：2019-02-18 18:05

【摘要】：自支撑分子筛不添加粘合剂且具有微孔-介孔结构,由于其活性高、质量和热传输速率快的特性吸引了研究者广泛关注。这些材料被称作多级孔分子筛,其具有传统分子筛的催化特性,存在大量的介孔和大孔结构显著提升了可接近性,增加分子传输速率。此外,自支撑分子筛不含粘合剂有效防止在粘合剂上发生副反应。本文以阴离子交换树脂球为模板成功合成出自支撑ZSM-5分子筛球。沸石咪唑酯骨架材料(ZIFs)是一类具有高孔隙率和稳定性的金属有机骨架材料(MOFs)。ZSM-5和ZIF-8都具有高比表面积和均一微孔,但二者在热稳定性、机械强度和结构灵活性上却有显著不同。本文使用一种温和的方法合成分子筛和ZIFs纳米复合材料。复合材料中,MOFs材料的优势(高比表面积和孔隙率)和分子筛材料的优势(高热稳定性和机械强度)被有效结合。本文对自支撑ZSM-5分子筛球和ZSM-5/ZIF-8复合物球的合成及其物理化学性质进行了研究。第一章介绍了自支撑分子筛和MOFs复合材料的合成方法,发展状况和应用前景。第二章介绍了使用阴离子交换树脂球作为模板制备自支撑ZSM-5分子筛球的方法。先将离子交换树脂球浸泡在ZSM-5分子筛前驱体溶液中进行水热处理。ZSM-5分子筛在离子交换树脂球孔中结晶形成ZSM-5/树脂复合材料。再煅烧除去有机离子交换树脂中的聚合物链,得到由尺寸为100nm的ZSM-5分子筛晶粒相互支撑形成的分子筛球。氮气吸附测试表明该材料具有微孔和介孔结构,介孔孔径为3nm,BET比表面积为427.777 m2 g-1。所合成样品具有良好的结晶度、机械强度和稳定性。第三章使用原位生长法制备ZSM-5/ZIF-8复合物球。将加热处理后的ZSM-5分子筛球浸泡在ZIF-8前驱体溶液中,再诱导ZIF-8在ZSM-5球内孔道中结晶生长。本章研究了该复合物球的物理化学性质。第四章使用温和的方法将尺寸为400nm的ZIF-8晶体固定在自支撑ZSM-5分子筛球表面。先用浓度为0.5mol/l的甲酸钠溶液将ZSM-5分子筛球进行表面修饰,再加入到ZIF-8前驱体溶液,诱导ZIF-8晶体在ZSM-5分子筛球表面生长。所合成样品具有良好的结晶度、机械强度和热稳定性。
[Abstract]:Self-supporting molecular sieves do not add binders and have microporous mesoporous structure. Because of their high activity, high mass and high heat transfer rate, self-supporting molecular sieves have attracted much attention. These materials are called multiporous molecular sieves. They have the catalytic properties of traditional molecular sieves. There are a large number of mesoporous and macroporous structures to enhance the accessibility and increase the molecular transport rate. In addition, self-supporting molecular sieves do not contain binders to effectively prevent side reactions on the binders. In this paper, the self supporting ZSM-5 molecular sieve spheres were successfully synthesized using anion exchange resin spheres as template. Zeolite imidazolide matrix material (ZIFs) is a kind of metal-organic skeleton material with high porosity and stability. Both (MOFs). ZSM-5 and ZIF-8 have high specific surface area and homogeneous micropore, but they have thermal stability. Mechanical strength and structural flexibility are significantly different. In this paper, molecular sieve and ZIFs nanocomposites were synthesized by a mild method. The advantages of MOFs materials (high specific surface area and porosity) and molecular sieve materials (high thermal stability and mechanical strength) were effectively combined in the composites. The synthesis and physical and chemical properties of self-supporting ZSM-5 molecular sieve spheres and ZSM-5/ZIF-8 complex spheres have been studied in this paper. In chapter 1, the synthesis, development and application prospect of self-supporting molecular sieve and MOFs composites are introduced. In chapter 2, the preparation of self-supporting ZSM-5 molecular sieve spheres using anion exchange resin spheres as template is introduced. First, the ion exchange resin spheres were immersed in the precursor solution of ZSM-5 molecular sieve for hydrothermal treatment. ZSM-5 molecular sieves crystallized in the ion exchange resin spheres to form ZSM-5/ resin composites. The polymer chain in the organic ion exchange resin was removed by calcination, and the molecular sieve ball was obtained by the support of the ZSM-5 molecular sieve grains of the size of 100nm. The nitrogen adsorption test showed that the material had micropore and mesoporous structure, and the mesoporous pore size was 3nmBET with a specific surface area of 427.777 m2 g ~ (-1). The synthesized samples have good crystallinity, mechanical strength and stability. In chapter 3, ZSM-5/ZIF-8 composite spheres were prepared by in situ growth method. The heated ZSM-5 molecular sieve spheres were immersed in the ZIF-8 precursor solution and then ZIF-8 was induced to crystallize in the ZSM-5 spheres. In this chapter, the physical and chemical properties of the composite spheres are studied. In chapter 4, ZIF-8 crystals of 400nm size are immobilized on the surface of self-supporting ZSM-5 molecular sieve spheres by mild method. The ZSM-5 molecular sieve spheres were first modified by sodium formate solution with concentration of 0.5mol/l and then added to the ZIF-8 precursor solution to induce ZIF-8 crystal to grow on the surface of ZSM-5 molecular sieve spheres. The synthesized samples have good crystallinity, mechanical strength and thermal stability.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ424.25;TB332

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