Silicalite-1分子筛膜的制备与表征

Preparation and Characterization of Silicalite-1 Membranes

考察了硅源、合成温度等合成条件对silicalite-1晶体在多孔支撑体上形成以及所合成的silicalite-1分子筛膜的分离性能的影响.结果表明,在185℃时采用非聚合态TEOS作为硅源进行合成需要40~50 h,而采用三聚合态的硅溶胶作硅源,其晶化温度降到175℃,合成时间仅为16 h.此外,采用硅溶胶作为硅源所合成膜的分离选择性明显好于TEOS合成的膜.XRD和SEM等表征显示,采用两种硅源都有纯的silicalite-1分子筛晶粒连续生长在莫来石支撑体外表面.

The synthesis conditions such as silica source and reaction temperature related to the formation of silicalite-1 zeolite layer on the porous supports and affected on the separation performance of silicalite-1 membranes were discussed. The results indicated that using the monomeric silica source TEOS the synthesis required the time of 40 - 50 h at 185 ℃, but that using the trimeric silica source colloidal silica required the reaction temperature as low as 175℃, and the time as short as 16 h. Moreover, the membranes prepared using the colloidal silica had generally better separation factor than those using TEOS. The characterization by XRD and SEM showed that using both silica source pure and intergrowth silicalite-1 crystals with random orientation were formed continuously on the outer surface of mullite tubes.