基于片状沸石Sodalite制备低缺陷的高效氢气分离膜

Zeolite membrane separation based on molecular sieving is an efficient and energy-saving separation method due to its superior properties such as high chemical stability, high selectivity, high thermal stability and long service life. However, there are several drawbacks, such as complicated fabrication process, abundant defects in membrane and hard to gain high selectivity and high permeance at the same time, in current fabrication method of zeolite membrane. To overcome this problem, the hydrogen separation membrane with both high selectivity and high permeance will be designed and produced in this project based on molecular sieving mechanism. First, according to the principle that the selectivity of zeolite membrane is determined by the pore structure and pore size of the zeolite, zeolite Sodalite with six-membered ring will be choose as materials for the zeolite membrane. The six-membered ring of zeolite Sodalite has the suitable size with the kinetic diameter of hydrogen molecule, so that hydrogen molecules would be allow to pass through the Sodalite membrane while other molecules with bigger size would be blocked by the membrane to lead to high hydrogen selectivity. Second, based on the key scientific problem of how to reduce the defects of the zeolite membrane and the interzeolite path to produce zeolite membrane with high performance, we will develop technology for the synthesis of sheet-like zeolite Sodalite and its precursor, and then to produce Sodalite membrane with the sheet-like zeolite Sodalite and its precursor. And last, we will develop synthesis methods for the production of thin Sodalite with few or single structure unit to produce ultrathin zeolite membrane which both have high hydrogen selectivity and high permeance. The results of this project will provide theoretical and experimental foundation for the application of the zeolite membrane.

沸石膜分离是一种高效节能的气体分离方式，然而，目前沸石膜的制备仍然存在着过程复杂、缺陷较多、选择性和渗透性难以兼顾等缺点。为克服这一难题，本项目拟基于分子筛分原理设计构筑具有高选择性和渗透性的氢气分离膜。首先我们根据沸石的孔道结构和尺寸决定了沸石膜对气体的选择性这一基本原理，选择孔道尺寸与氢气分子动态直径相当的六元环沸石Sodalite作为氢气分离膜的主要材料以提高氢气的选择性。其次基于如何减少膜内沸石间路径、降低膜缺陷这一制备高性能气体分离膜的关键科学问题，我们将发展片状沸石Sodalite及其前体的可控制备技术，基于片状沸石Sodalite及其前体发展成膜方法以得到具有高氢气选择性的沸石膜。最后，我们将发展具有少层甚至单层沸石基本结构单元的Sodalite薄层的合成方法，以制备同时具有高选择性与高渗透性的超薄沸石膜，为沸石膜的实际应用打下理论和实验基础

层状硅酸盐RUB-15是沸石分子筛Sodalite的前驱体，其具有和Sodalite相似的笼状结构且具有独特的层状结构，在功能材料和无机膜材料的制备方面都有着很好的应用前景。本项目的主要研究内容就是围绕着RUB-15展开的，并进行了拓展性研究。RUB-15的特殊层状结构和层间的可交换离子让它成为了一个能够进行填充和修饰的载体，基于此，我们制备了二维层状金属氧化物Fe3O4纳米薄片、Ag/SiO2层状复合材料、Pd/GLC层状材料、NPS掺杂的层状碳材料等，在催化降解有机污染物、4-硝基苯酚的还原和苯乙烯加氢等领域表现出了很好的催化性能。进一步，通过抽虑成膜或剥离成膜等方法制得了RUB-15的薄膜，该薄膜对氢气具有很好的选择性，能够应用于含氢气混合物的分离纯化。最后，我们通过简单调控温度响应聚合物在氧化石墨烯（GO）上的接枝密度，制备了具有正/负可逆门控规律的温度响应GO膜。我们将具有相反门控性质的GO膜结合在一起，设计了一种具有自适应性的流体系统，在智能分离、流体可控输运中均表现出优异的性质。另外，在拓展性研究方面，我们又结合静电纺丝技术制备了具有纤维结构的功能催化材料，在光催化分解水和降解有机污染物方面表现出了很好的催化性能。本项目的研究内容在热催化、光催化和分离领域都有一定的应用前景。在本项目的资助下，项目组成员共发表SCI论文13篇，申请专利2项，授权专利2项，培养硕士和博士研究生7名。