title: Tailoring the Transport Properties of Zeolitic Imidazolate Frameworks by Post-Synthetic Thermal Modification.
abstract: Understanding how to control transport properties of zeolitic imidazolate frameworks (ZIFs) is critical to extend ZIF-based membranes and adsorbents to a wide spectrum of gas and vapor separations. In this work, we report a facile post-synthetic thermal modification (PSTM) technique to tailor ZIFs' transport properties by balancing diffusivity and diffusion selectivity. With controllable dissociation of framework methyl groups from a precursor ZIF (ZIF-8), we have prepared thermally modified ZIFs showing substantially increased n-butane diffusivity and attractive n/iso-butane diffusion selectivity. Hybrid ZIF/polymer mixed-matrix membranes formed using these thermally modified ZIFs are expected to deliver attractive butane isomer separation performance. Membranes based on such materials can potentially be used to retrofit refinery alkylation units for producing premium gasoline blending stocks.
authors.affiliation: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Dr. NW, Atlanta, Georgia 30332-0100, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Dr. NW, Atlanta, Georgia 30332-0100, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: Koros
keywords: butane isomer separation; diffusion selectivity; membrane gas separation; metal−organic frameworks; mixed-matrix membrane; nanoporous materials; thermal treatment