预涂布晶种法合成无缺陷A型分子筛膜的研究

采用一种颗粒度约为 2 0 0 nm的胶态 A型分子筛为晶种源 ,对晶种层进行特殊的蒸气处理后 ,进一步采取原位水热晶化法 ,在多孔氧化铝载体表面制备出 A型分子筛膜 .膜分子筛以特殊的孪生聚晶形式生长在一起 ,可有效地消除晶粒间隙 ,形成致密的分子筛膜层 .晶化反应液的碱度对 A型分子筛膜的质量影响很大 ,低碱度更有利于 A型分子筛膜的生长 .在对分子筛膜进行高温活化处理过程中产生一些缺陷孔 ,降低了膜气体分离性

Preparation and Characterization of Sililcalite 1 Zeolite Films in Weak acid Medium

在SIO2-TPAbr-nH4f-H2O弱酸性氟离子体系中，在玻璃基片上采用水热晶化法制备了SIlICAlITE-1（全硅zSM-5）分子筛膜.通过Xrd，SEM分析测试手段对所合成的分子筛膜进行了表征，并对膜合成中硅源，水量等影响因素进行了考察.Silicalite 1 (pure silica ZSM 5) has been hydrathermally synthesized on the surface of silica glass in weak acid medium.The resulting films have been characterizaated by X ray diffraction and scanning electron microscope.Theinflunce of silica source, water content in the film formation have been studied

Dense A-type zeolite membrane synthesized by seeding

The synthesis of A-type zeolite membranes on porous alpha -Al2O3 supports via the method of seeding plus secondary hydrothermal crystallization has been studied. The seed layers, which were prepared from colloidal A-type zeolite synthesized from the reaction mixture of n[(TMA)(2)O] : n(SiO2) n (Al2O3) : n(Na2O) : n(H2O) = 13.4 : 11.25 : 1.8 : 0.3 : 700, were treated by steam of ammonia to inhibit the formation of cracks when dried. Compact zeolite membranes constituted with multiple-twined zeolite crystals were accessed by hydrothermal growth of seed layers in the reaction sol of n (Na2O) n(Al2O3) : n(SiO2) = n(H2O) = 3 : 1 : 1 : 800. In highly alkaline hydrothermal solutions, seed layers tended to dissolve and loose zeolite membranes with many defects were obtained. The gas permeanbility on A-type zeolite membrane dried at 393 K, in which water molecular still inhabited the zeolitic channels, was quite low, suggesting that the membrane was close to free of defects. Defects were formed mainly due to different thermal expansion coefficients between alpha -Al2O3 support and zeolite membrane when the calcinations at 823 K was carried out to free the channel of membrane zeolites