ABSTRACT
The metal-organic framework ZIF-8, which undergoes hydrolysis under hydrothermal conditions, is endowed with high water-resistance after a shell-ligand-exchange-reaction. The stabilized ZIF-8 retains its structural characteristics with improved application performances in adsorption and membrane separation.
Subject(s)
Infrared Rays , Membranes, Artificial , Metals/chemistry , Models, Molecular , Organic Chemicals/chemistry , Adsorption , Carbon Dioxide/chemistry , Carbon Dioxide/isolation & purification , Diffusion , Methane/chemistry , Methane/isolation & purification , Microscopy , Monte Carlo MethodABSTRACT
Diffusion is known to be quantified by measuring the rate of molecular fluxes in the direction of falling concentration. In contrast with intuition, considering methanol diffusion in a novel type of nanoporous material (MOF ZIF-8), this rate has now been found to be enhanced rather than slowed down by an opposing flux of labeled molecules. In terms of the key quantities of random particle movement, this result means that the self-diffusivity exceeds the transport diffusivity. It is rationalized by considering the strong intermolecular interaction and the dominating role of intercage hopping in mass transfer in the systems under study.
ABSTRACT
A zeolitic imidazolate framework (ZIF-8) as member of the metal-organic framework family has been crystallized as a thin porous layer on an asymmetric ceramic support. Hydrogen can be selected from other gases by molecular sieving.
