Facile synthesis of LTA molecular sieve membranes on covalently functionalized supports by using diisocyanates as molecular linkers
Facile synthesis of LTA molecular sieve membranes on covalently functionalized supports by using diisocyanates as molecular linkers
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DOI：
10.1039/c1jm11549a
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发表时间：
2011-01-01
影响因子：
--
通讯作者：
Caro, Juergen
中科院分区：
文献类型：
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作者：
Huang, Aisheng;Caro, Juergen
人们在亲水LTA沸石膜的制备方面付出了很多努力，这些LTA沸石膜在亲水分离中表现出了优异的性能。然而，关于在LTA沸石膜上成功对气体混合物进行择形分离的报道很少，迄今为止报道的大多数分离因子都低于相应的努森常数。人们经常发现沸石LTA膜含有晶间缺陷，从而降低了其分离选择性，这是由于支撑表面上的孤立晶体生长在一起形成连续的支撑LTA层的问题造成的。在目前的工作中，通过异氰酸酯基团与表面羟基反应形成的氨基甲酸酯键，开发了一种简便的合成方法，通过使用1,4-二异氰酸酯作为分子粘合剂将沸石营养物锚定到载体表面上，无需晶种制备负载型致密LTA沸石层。厚度约为3.5μm的α-Al(2)O(3)负载沸石LTA膜在气体渗透测试中表现出分子筛性能。
Much effort has been paid towards the preparation of hydrophilic zeolite LTA membranes, and these zeolite LTA membranes have showed excellent performance in hydrophilic separations. However, there are only a few reports on successful shape-selective separations of gas mixtures on zeolite LTA membranes, most separation factors reported so far were lower than the corresponding Knudsen constants. It is often found that zeolite LTA membranes contain inter-crystalline defects to degrade their separation selectivity, which result from the problems that the isolated crystals on the support surface grow together to form a continuous supported LTA layer. In the present work, via urethane bonds formed by the reaction of isocyanate groups with surface hydroxyls, a facile synthesis method is developed for the seeding-free preparation of supported dense zeolite LTA layers by using 1,4-diisocyanate as a molecular binder to anchor the zeolite nutrients onto the support surface. The alpha-Al(2)O(3) supported zeolite LTA membrane with a thickness of about 3.5 mu m displays molecular sieving performance in gas permeation tests.