Paralyzed membrane: Current-driven synthesis of a metal-organic framework with sharpened propene/propane separation

Abstract

ZIF-8 membranes with inborn-suppressed linker mobility sharpen molecular sieving with C3H6/C3H8 separation factor above 300.

Polycrystalline Advanced Microporous Framework Membranes for Efficient Separation of Small Molecules and Ions

“…The direct synthesis of MOF membrane under external electric field has been proven to be a better way for constructing ZIF‐8 polymorphic membrane with a higher ratio of uncubic polymorph and a more stable crystal phase. A ZIF‐8 polymorphic membrane, composed of crystals in mainly monoclinic ( Cm ) (70.98%) and mixed with R 3 m (24.42%) and I −43 m (4.6%) space groups, was recently fabricated on planar conducing supports through a local in situ electric field driving ( Figure a) . A 200 nm thin continuous ZIF‐8 selective layer can be easily prepared within 20 min at room temperature with a current density of −0.7 mA cm −2 .…”

“…ZIF‐8 synthesized by FCDS has a Cm group, which is a stiffer structure than solvothermally synthesized ZIF‐8 in I −43 m groups; thus, a higher propene/propane separation factor can be obtained. Reproduced with permission . Copyright 2018, AAAS.…”

Ultrathin permselective membranes: the latent way for efficient gas separation

“…Electrophoretic deposition has been used for quite some time to deposit charged colloids on to a substrate with the help of an electric eld (e.g., zeolite particles as seeds to growth a zeolite membrane) 82 and has been recently demonstrated to synthesis sub-1 mm-thick high-performance MOF membranes. [83][84][85] The ux of the colloids, N, is related to their concentration (c) and their velocity (v), as per eqn (3). v can be obtained from the mobility of colloid under the applied electric eld, E (eqn (4)).…”

“…Interestingly, the synthesis of ZIF-8 membranes using fast-current-driven synthesis under an electric eld can lead to sharpened molecular sieving performance, as shown recently by Zhou et al, achieving propene/ propane selectivity of greater than 300. 85…”

Solvent‐free route for metal–organic framework membranes growth aiming for efficient gas separation

“…In the last decade, MOFs have been reported to be effective as membrane materials to separate gas molecules, such as H 2 /CO 2, CO 2 /CH 4, and C 3 H 6 /C 3 H 8. However, the industrial application of MOF membranes is still lacked, which is largely limited by the complicated fabrication methods, which are not suitable for industrial scale‐up production.…”