可持续发展路线合成分子筛

发布时间：2018-06-01 06:17

本文选题：可持续发展 + 无有机模板剂合成　；参考：《浙江大学》2017年博士论文

【摘要】：当今世界,能源是国家的命脉,也是工业与民生的基石,任何一个国家和社会的存在与发展都离不开能源。随着地球上资源的不断消耗,开发新的材料、提升现有材料的催化效益和发现新能源成为大家关注的焦点。沸石分子筛作为一种重要的环境友好型多孔纳米催化材料,因具有有序的微孔结构、大比表面积和较高的稳定性,在石油化工、离子交换和环境催化等方面扮演着重要角色。当然,能源的开发和利用要建立在经济与环保基础上,因而这些材料的合成过程要走可持续发展合成路线。当前,大部分分子筛是在有机模板剂导向作用下水热法合成的,模板剂的使用会增加成本和污染环境;而大量水溶剂的使用既浪费水资源,废水的排放又会污染环境。因此,特别需要在分子筛的合成路线中避免使用有机模板剂和大量的水溶剂。本文旨在发展可持续发展合成路线,即无有机模板剂合成法和无溶剂合成法来合成分子筛。本论文首次在不添加有机模板剂的条件下晶种法合成了高硅ZSM-22分子筛,其方法是在硅铝初始凝胶中将ZSM-22晶种溶解形成次级结构单元,诱导分子筛晶核的产生,然后快速晶化形成ZSM-22分子筛。利用晶种法合成的ZSM-22分子筛具有很高的硅利用率,而一般用无有机模板法合成的分子筛硅的利用率都相对较低。上述晶种法使用的晶种是在有机模板剂存在下合成的,所合成的产物间接地使用了有机模板剂。为了彻底避免有机模板剂的使用,介绍了一种通过调节硅铝初始凝胶的组成,在无有机模板剂和无晶种的条件下合成高硅ZSM-22分子筛的方法,该过程依然保持很高的硅利用率。最新发展的无溶剂合成法只需将固体原料研磨均匀,加热晶化后即可得到目标分子筛,是一条可持续发展合成路线。本文通过使用廉价易得的环己胺模板剂,首次在无溶剂条件下合成了结晶度良好的B-MWW分子筛。该方法避免了大量水溶剂的使用,单釜效率高,B-MCM-22分子筛骨架中的B原子易脱去,可以被A1和Ti等原子同晶取代从而引入催化活性位点。水热法合成的EMT分子筛的单釜效率极低,而本论文发展了一种在低温体系下通过调节硅铝初始原料的组成来无溶剂和无有机模板剂合成分子筛的方法。该合成过程单釜效率高,EMT分子筛具有较高的离子交换能力。
[Abstract]:In today's world, energy is the lifeblood of the country and the cornerstone of industry and people's livelihood. The existence and development of any country and society can not be separated from energy. With the continuous consumption of resources on the earth, the development of new materials, enhance the catalytic efficiency of existing materials and find new energy become the focus of attention. As an important environment-friendly porous nano-catalytic material, zeolite plays an important role in petrochemical industry, ion exchange and environmental catalysis because of its ordered micropore structure, large specific surface area and high stability. Of course, the development and utilization of energy should be based on economic and environmental protection, so the synthetic process of these materials should follow the route of sustainable development. At present, most of molecular sieves are synthesized by hydrothermal method under the guidance of organic templates. The use of templates will increase the cost and pollute the environment, while the use of a large amount of water solvents will not only waste water resources, but also pollute the environment. Therefore, it is particularly necessary to avoid the use of organic templates and a large amount of water solvents in the synthetic routes of molecular sieves. The purpose of this paper is to develop a sustainable synthetic route, that is, organic template free synthesis and solvent free synthesis to synthesize molecular sieve. In this paper, high silicon ZSM-22 molecular sieve was synthesized by seed method without organic template for the first time. The method was to dissolve the ZSM-22 seed into secondary structure unit in the initial silica aluminum gel to induce the nucleation of molecular sieve. Then the ZSM-22 molecular sieve was rapidly crystallized. The ZSM-22 molecular sieve synthesized by the method of crystal seed has a high silicon utilization ratio, but the utilization ratio of the molecular sieve synthesized by the organic template method is relatively low. The seeds used in the above method were synthesized in the presence of organic templates, and the synthesized products indirectly used organic templates. In order to avoid the use of organic template completely, a method of synthesizing high silicon ZSM-22 molecular sieve without organic template and without crystal seeds by adjusting the composition of initial gel of silicon and aluminum is introduced. The process still keeps high silicon utilization rate. The newly developed solvent-free synthesis method only needs to grind the solid materials uniformly and get the target molecular sieve after heating crystallization. It is a sustainable synthetic route. In this paper, B-MWW molecular sieve with good crystallinity was synthesized by using cheap and easy to obtain cyclohexylamine template. This method avoids the use of a large amount of water solvents, and the B atoms in the framework of B-MCM-22 molecular sieve with high efficiency can be easily removed, and can be replaced by atoms such as A1 and Ti, thus introducing the catalytic active sites. The efficiency of hydrothermal synthesis of EMT molecular sieve is very low. In this paper, a solvent-free and organic template free synthesis method of EMT molecular sieve was developed by adjusting the composition of the initial raw material of Si-Al at low temperature. The EMT molecular sieve with high efficiency in this synthesis process has high ion exchange ability.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ424.25

【相似文献】