在多孔陶瓷载体上X型分子筛生长成膜的研究

Preparation of Zeolite X Membranes on Mesoporous Ceramic Substrates

研究X型分子筛在多孔陶瓷载体上的生长条件 ,合成膜的晶化液组成n(SiO2 ) /n(Al2 O3) =3 .0～ 5 .0 ,n(Na2 O) /n(SiO2 ) =1.3～ 9.8,n(H2 O) /n(SiO2 ) =12 0～ 80 0 ;晶化温度 85～ 10 5℃ ;晶化时间 2 4～ 96h。SEM显示多孔陶瓷载体上负载生长分子筛膜要经过 6～ 7次涂膜操作 ,才能获得较理想的均匀连续的顶膜 ,膜厚 10～ 2 5 μm。考察了晶化液的配方、合成条件及晶化次数对分子筛负载量的影响 ,多孔载体的表面形貌及规格对表面膜均匀连续性的影响等。结果表明 ,成膜的渗透通量下降为载体的 7%～ 9% ,分子筛膜选透率用 (C4H9) 3N和 (C4F9) 3N的纯蒸汽表征 ,在 3 5 0℃下 (C4H9) 3N对 (C4F9) 3N的选透率达到 69。

A method has been developed by which zeolite X can be grown on the surface of microporous ceramic cylinder on the basis of classical synthesis of zeolite X.The recipe of crystallization solution for the synthesis of zeolite X type membrane is n(SiO 2)/n(Al 2O 3)=3.0～5.0,n(Na 2O)/n(SiO 2)=1.3～9.8,n(H 2O)/n(SiO 2)=120～800,crystallization temperature 85～105 ℃,and crystallization time 24～96 h.The crystal species growing on the top layer of the ceramic cylinders were characterized by XRD.The morphology of substrates after crystallization was characterized by SEM.The experimental results indicate that a continuous and crack-free top layer of zeolite X membrane with a thickness of 10～25 μm can be grown on ceramic substrates after crystallization for six or seven times.The effect of concentration of synthesis solution,crystallization times and cylindrical specification on the morphology of top layer on synthesized substrate was investigated.The permeability of synthesized membrane decreased to 7%～9% of that of the substrate.And further,the ratio of permeabilities of (C 4H 9) 3N to (C 4F 9) 3N can reach 69 at 350 ℃. [