||Grain size control of ZIF-8 membranes by seeding-free aqueous synthesis and their performances in propylene/propane separation
TANAKA, Shunsuke ,
OKUBO, Kenta ,
KIDA, Koji ,
SUGITA, MikiTAKEWAKI, Takahiko
Journal of Membrane Science
311 , 2017-12-15 , Elsevier
This work was financially supported by the Kansai University fund for Supporting Young Scholars,2015.
Polycrystalline ZIF-8 membranes of about 1 µm in thickness were successfully grown on α-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 H2 from CO2, N2, CH4, and C3H6 ever so slightly increased with the graft density, the ideal permselectivity of C3H6/C3H8 increased rapidly and reached 36 with corresponding C3H6 permeance of 8.5 × 10−8 mol/m2 s Pa. As a conclusion of the combined characterization with adsorption analysis, it was found that the sieving of C3H6/C3H8 by our seeding-free aqueous-synthesized ZIF-8 membrane is mainly governed by diffusion-driven separation process.