Screening metal-organic framework materials for membrane-based methane/carbon dioxide separations

Abstract

Metal-organic frameworks (MOF) are a diverse family of highly porous materials that have potential advantages as adsorbents and membranes for gas separations. Because the fabrication of membranes from crystalline materials is challenging, nothing is currently known about what advantages MOFs may have over more conventional materials for membrane-based separations. We use atomically detailed simulations to present the first information about the performance of MOFs as membranes for gas separations using the separation of CO 2/CH 4 mixtures by MOF-5 as an example. Describing membrane performance requires information about both mixture adsorption and mixture diffusion in the membrane material. Our results show that mixture effects play a crucial role in determining the performance of MOF-5 membranes under conditions relevant for natural-gas applications, indicating that modeling or experimental studies that examine only single-component gases will be insufficient to understand the properties of MOF-based membranes in practical applications. © 2007 American Chemical Society.