| 초록 |
Zeolitic imidazolate frameworks (ZIFs) are porous hybrid materials, having unique properties such as high surface areas, tunable regular micro-pores with thermal and chemical stability. Among various ZIFs, ZIF-8 is composed of zinc ions (Zn2+) and 2-methylimidazole (H-mIm). If ZIF-8 are prepared in a film or membrane form, it can be directly used for gas separations by molecular sieving mechanism. For the successful fabrication of ZIF-8 membranes using secondary growth method, the size of seed particles and the adhesion between seed layer and support are important factors. In this study, ZIF-8 seed layer was synthesized by conversion synthesis of ZnO layer on support in H-mIm solution, followed by the secondary growth synthesis of ZIF-8 membranes. The parameters of conversion seeding were investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate of ZIF-8. The ZIF-8 membranes showed better coverage of seeding layer and improved propylene/propane gas separation properties compared with the membranes prepared by traditional dip-coating seeding. |
