摘要
通过对X型分子筛合成方法的改进 ,获得了适合分子筛在多孔不锈钢载体上成长的条件 .通过在不同孔径的多孔不锈钢载体上负载生长分子筛膜 ,研究了X型分子筛在多孔不锈钢载体上生长的规律 ,考察了晶化液配比、合成条件及晶化次数对分子筛负载量的影响 ,还考察了多孔载体的表面形貌及孔径大小对表面膜均匀连续性的影响等 .
Porous stainless steel (PSS) tubes have a property of high strength, and are easy to be equipped as a membrane module. In this paper, a method for zeolite X growing on the surface of PSS cylinder on the basis of the classic synthesis has been developed. The recipe of crystallization solution for synthesis of zeolite X membrane is (1 3～6 0)Na 2O SiO 2 (0 20～0 33)Al 2O 3 (120～500)H 2O, the crystallization temperature is 85～100 ℃, and the crystallization time is 40～84 h. Instead of ceramic ones, PSS substrate can not release aluminium ion in in situ synthesis, therefore, the composition of synthesis solution can be controlled by the starting recipe. It is especially important when the zeolite membranes with high ratio of Si/Al are needed. The experimental results indicated that a continuous and crackfree toplayer of zeolite X membrane with a thickness of 5～20 μm can be grown on PSS tubes by 4 coating times and more, and the morphology of toplayer on the substrate depends on the recipe of coating solution, crystallization condition, coating times and pore size of the substrate. The permeance of pure He and N 2 through zeolite X/PSS decreased to 0 03%～0 50%, compared with that through PSS. n Butane, i butane and neopentane have nearly the same permeance of 13 nmol/(m 2·s·Pa) at 25 ℃, showing no preferential permeation to n butane. And further, the ratio of permeance of (C 4H 9) 3N to (C 4F 9) 3N reaches up to 57 3 at 350 ℃ after 6 coating times. It is indicated that there still exist non zeolite apertures as gas pathways on the toplayer of zeolite X/PSS.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2000年第2期151-155,共5页
关键词
分子筛膜
多孔不锈钢
制备
X型分子筛
zeolite membrane, porous stainless steel, preparation, characterization, membrane separation
