NaA分子筛膜的合成及其表征

The Synthesis and Characterization of Zeolite NaA Membrane

分别采用原位水热二次合成法、微波密闭合成法,在管状-αAl2O3陶瓷管的外表面上合成出了一系列的NaA型分子筛膜,考察了四种原料配比、四种涂晶方法对合成分子筛膜的影响,对合成条件进行了优化.分别采用XRD、SEM、及乙醇水溶液的渗透汽化实验(用氮气吹扫渗透侧作渗透推动力)对合成的膜进行了表征.结果表明当原料配比为Na2O∶Al2O3∶SiO2∶H2O=1∶1∶3.6∶100,清液涂晶种,微波密闭合成出的分子筛膜对水和乙醇的选择性较好,分离因子远远大于空白管的分离因子,95%(wt)的乙醇水溶液通过膜渗透后,渗透侧乙醇的含量则降至21%(wt),水的含量升高到79%(wt),分离因子可达63.8.

NaA zeolite membrane is prepared on the outer surface of porous - alumina ceramic tuber by hydrothermal method and airtight microwave method. Four different molar ratios and four dip-coating methods are investigated in this paper. The crystal of NaA zeolite membrane is characterized by XRD and SEM . The separating property of the membrane is evaluated by pervaporation of ethanol/water mixture at m（C2H5OH）/m（H2O） = 95：5. We found that the membrane, synthesized by airtight microwave method at the molar ratio of Na2O：Al2O3：SiO2：H2O = 1：1：3.6： 100, dip-coated by clear seed solution performs better than other membrane. The mixture permeating through this membrane is composed of water 79% （wt）and ethanol 21% （wt）, and the separation factor reaches 63.8, which shows that the water permeating through the NaA zeolite membrane selectively and the NaA zeolite tuber membrane has a superiority of selectivity than the porous - alumina ceramic tuber visibly.