Effect of Solution Concentration on Structure and Permeation Properties of ZIF-8 Membranes for Propylene/Propane Separation
Effect of Solution Concentration on Structure and Permeation Properties of ZIF-8 Membranes for Propylene/Propane Separation
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DOI：
10.1252/jcej.15we038
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发表时间：
2016-02-01
影响因子：
0.8
通讯作者：
Yamaguchi, Takeo
中科院分区：
文献类型：
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作者：
Hara, Nobuo;Yoshimune, Miki;Yamaguchi, Takeo
逆扩散法是制备咪唑骨架8分子筛（ZIF-8）丙烯/丙烷分离膜的一种有吸引力的方法。在本研究中，澄清溶液的浓度对ZIF-8膜的结构和单组分和二元气体渗透性能的多孔a-氧化铝中空毛细管基板上制备的评价，以探讨成膜机理。使用不同浓度的2-甲基咪唑和硝酸锌的甲醇溶液制备ZIF-8膜，其中2-甲基咪唑与硝酸锌的固定摩尔比为4。增加溶液浓度导致基底内ZIF-8层的覆盖增加，并且最终甚至在基底的内表面上产生ZIF-8层。较高的溶液浓度有利于溶质在反扩散法中的相互扩散。使用丙烯和丙烷的等摩尔混合物在298 K下经受0.1 MPa的总压差进行的二元渗透测量得到丙烯渗透率为7.0 × 10（-9）mol.m（-2）.s（-1）.Pa-1，最大达到的丙烯/丙烷选择性为42。
The counter-diffusion method is an attractive approach for the preparation of zeolitic imidazolate framework-8 (ZIF-8) membranes for propylene/propane separation. In the present study, the effects of the preparation-solution concentration on the structure and the single-component and binary gas permeation properties of ZIF-8 membranes prepared on a porous a-alumina hollow capillary substrate were evaluated in order to explore the mechanism of membrane formation. ZIF-8 membranes were prepared using various concentrations of methanolic 2-methylimidazole and zinc nitrate solutions with a fixed molar ratio of 2-methylimidazole to zinc nitrate of 4. Increasing the solution concentration led to increased coverage of the ZIF-8 layer within the substrate, and ZIF-8 layers were eventually generated even on the inner surface of the substrate. A higher solution concentration facilitated inter-diffusion of the solutes in the counter-diffusion method. Binary permeation measurements using an equimolar mixture of propylene and propane subjected to a total pressure difference of 0.1 MPa at 298 K gave rise to a propylene permeance of 7.0 x 10(-9) mol.m(-2).s(-1).Pa-1 with a maximum achieved propylene/propane selectivity of 42.