Grain size control of ZIF-8 membranes by seeding-free aqueous synthesis and their performances in propylene/propane separation
Grain size control of ZIF-8 membranes by seeding-free aqueous synthesis and their performances in propylene/propane separation
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DOI：
10.1016/j.memsci.2017.09.037
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发表时间：
2017-12
影响因子：
9.5
通讯作者：
S. Tanaka;K. Okubo;Koji Kida;Miki Sugita;T. Takewaki
中科院分区：
文献类型：
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作者：
S. Tanaka;K. Okubo;Koji Kida;Miki Sugita;T. Takewaki
通过无晶种水合成，在 α-氧化铝多孔载体上成功生长了厚度约 1 µm 的多晶 ZIF-8 膜。为了实现连续良好共生的膜，通过化学修饰在载体上形成ZIF-8的假表面。我们在水性系统中的膜制备基于支撑表面活化概念来控制成核位点的表面密度。多晶膜的晶粒尺寸与类配体表面改性剂的接枝密度直接相关。使用 H2、CO2、N2、CH4、C3H6 和 C3H8 研究单组分气体渗透性能。虽然 H2 来自 CO2、N2、CH4 和 C3H6 的理想选择性渗透率随着接枝密度的增加而略有增加，但 C3H6/C3H8 的理想选择性渗透率迅速增加并达到 36，相应的 C3H6 渗透率为 8.5 × 10−8mol/m2s Pa。综合表征和吸附分析得出的结论是，我们的无晶种水合成 ZIF-8 膜的 C3H6/C3H8 主要受扩散驱动的分离过程控制。
Polycrystalline ZIF-8 membranes of about 1 µm in thickness were successfully grown onα-alumina porous support by seeding-free aqueous synthesis. In order to achieve continuous well-intergrown membranes, a pseudo-surface of ZIF-8 was formed on the support by chemical modification. Our membrane preparation in aqueous system is based on the support-surface activation concept to control the surface density of nucleation sites. The grain size of polycrystalline membrane is directly related to a graft density of ligand-analogous surface modifier. Single-component gas permeation properties were investigated using H2, CO2, N2, CH4, C3H6, and C3H8. While the ideal permselectivities of H2from CO2, N2, CH4, and C3H6ever so slightly increased with the graft density, the ideal permselectivity of C3H6/C3H8increased rapidly and reached 36 with corresponding C3H6permeance of 8.5 × 10−8mol/m2s Pa. As a conclusion of the combined characterization with adsorption analysis, it was found that the sieving of C3H6/C3H8by our seeding-free aqueous-synthesized ZIF-8 membrane is mainly governed by diffusion-driven separation process.