构建超薄硅基分子筛薄膜及其有机异构体的高通量分离

项目名称： 构建超薄硅基分子筛薄膜及其有机异构体的高通量分离

项目编号： No.21501024

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 邹小勤

作者单位： 东北师范大学

项目金额： 20万元

中文摘要： 分子筛薄膜的通量是衡量膜气体分离性能的重要指标，其主要影响因素包括：分子筛自身的孔隙率、薄膜面积、薄膜厚度，其中薄膜厚度是影响膜通量至关重要的参数之一。因此合成超薄分子筛膜可以有效地提高薄膜通量。目前，大多数制备的分子筛薄膜厚度基本在微米级以上；且制备方法过于单一，很难总结出合成的规律性和方法的广谱性。本项目拟引入长链型多铵类化合物为有机模板剂用于具有单层分子筛结构单元厚度纳米晶的合成；并将此纳米晶作为晶种，采用二次合成法弥补晶种之间的晶体间隙，通过控制晶体在二次生长中的生长速度，从而获得连续致密超薄的硅基分子筛膜（CHA、MFI、BETA）。晶种在薄膜中二次生长的规律通过耦合原位原子力显微镜与X-光衍射、扫描电子显微镜、透射电子显微镜等技术手段进行研究，进而揭示晶种法合成分子筛膜的机理。合成的超薄连续致密的硅基分子筛膜应用于分离分子尺寸接近的有机异构体，从而真正实现分子筛筛分效果。

中文关键词： 超薄分子筛膜；多铵有机模板剂；成膜机理；高通量；异构体分离

英文摘要： It is widely accepted that gas permeability is practically important for zeolite membranes in gas separations. But the diffusion limitations of gases in small pores adversely affect the gas permeability across zeolite membranes. This problem can be overcome by increasing zeolite porosities and effective membrane surface areas, reducing membrane thickness, and etc. In principle, high permeability can be achieved with thin membranes. Thus, there are four basic objectives in this project: (1) to design ultra-thin zeolite membranes for gas separations, which are in contrast to previous efforts in the preparation of different thick membranes with a variety of zeolite structures (the membrane thickness is usually above 1 µm); (2) to propose a general synthesis method for the fabrications of ultra-thin zeolite membranes; (3) to elucidate the formation mechanism of zeolite membranes; (4) to explore the potential applications of ultra-thin membranes in gas separations, and to build up a separation model of gas permeation through zeolite membranes. The above goal will be achieved via the following reasonable routes: (1) the ultra-thin membranes will be prepared by secondary crystallization of seeded layers with small nanocrystals which are hydrothermally synthesized using a long-chained multi quaternary ammonium-type organic template; (2) the preparations of ultra-thin CHA、MFI、BETA-type zeolite membranes will be exemplified using this proposed strategy (assisted approach with ultra-small crystallites as seeds); (3) the crystallization behaviors of zeolite membranes (crystal overgrowth, oriented growth, etc.) will be studied by in-situ atomic force microscopy (AFM) in couple with X-ray diffraction, scanning electronic microscopy, transmission electron microscopy and other techniques; (4) the separation of organic isomers will be carried out on prepared ultra-thin membranes.

英文关键词： Ultra-thin Zeolite Membranes;Multi Quaternary Ammonium-type Organic Template;Membrane Formation Mechanism;High Permeability;Isomer Separation