抄録
ZIF–8 is a flexible zeolitic imidazole-based metal organic framework (MOF) whose narrow pore apertures swing open by reorientation of imidazolate linkers and expand when probed with guest molecules. An interesting feature of the ZIF–8 MOF is that its crystal size can be varied over a wide range of values (typically from approximately 50 nm to 100 µ m), something that is very hard to achieve with classical porous aluminosilicates. Such crystal size engineering might be exploited to tune the adsorptive and diffusion properties of the material for molecular separation processes. Our studies have aimed at carefully preparing ZIF–8 samples of different crystal size with identical structural and chemical properties to allow an accurate analysis of the effect of crystal size on adsorption and diffusion of guest molecules into the ZIF–8 MOF. Additionally, a simple, facile, and convenient route for in situ aqueous synthesis of well-intergrown ZIF–8 membranes has been developed. This review provides an overview of the aqueous synthesis of ZIF–8 MOF with emphasis on the morphology control and discusses recent progress in ZIF membranes and the challenges and opportunities for future membrane separation technology using MOF.
