Choi Jungkyu, Jeong Hae-Kwon, Snyder Mark A, Stoeger Jared A, Masel Richard I, Tsapatsis Michael
Department of Chemical Engineering and Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, Minneapolis, MN 55455, USA.
Science. 2009 Jul 31;325(5940):590-3. doi: 10.1126/science.1176095.
Microporous molecular sieve catalysts and adsorbents discriminate molecules on the basis of size and shape. Interest in molecular sieve films stems from their potential for energy-efficient membrane separations. However, grain boundary defects, formed in response to stresses induced by heat treatment, compromise their selectivity by creating nonselective transport pathways for permeating molecules. We show that rapid thermal processing can improve the separation performance of thick columnar films of a certain zeolite (silicalite-1) by eliminating grain boundary defects, possibly by strengthening grain bonding at the grain boundaries. This methodology enables the preparation of silicalite-1 membranes with high separation performance for aromatic and linear versus branched hydrocarbon isomers and holds promise for realizing high-throughput and scalable production of these zeolite membranes with improved energy efficiency.
微孔分子筛催化剂和吸附剂根据分子的大小和形状来区分分子。对分子筛膜的兴趣源于其在节能膜分离方面的潜力。然而，由于热处理引起的应力而形成的晶界缺陷，通过为渗透分子创造非选择性传输途径，损害了它们的选择性。我们表明，快速热处理可以通过消除晶界缺陷来提高某一沸石（硅沸石-1）厚柱状膜的分离性能，这可能是通过加强晶界处的晶粒结合来实现的。这种方法能够制备出对芳烃以及直链与支链烃异构体具有高分离性能的硅沸石-1膜，并有望实现这些沸石膜的高通量和可扩展生产，同时提高能源效率。
