Hydrogen‐Bonded Polyimide/Metal‐Organic Framework Hybrid Membranes for Ultrafast Separations of Multiple Gas Pairs

Abstract

Membranes have seen a growing role in mitigating the extensive energy used for gas separations. Further expanding their effectiveness in reducing the energy penalty requires a fast separation process via a facile technique readily integrated with industrial membrane formation platforms, which has remained a challenge. Here, an ultrapermeable polyimide/metal-organic framework (MOF) hybrid membrane is reported, enabling ultrafast gas separations for multiple applications (e.g., CO 2 capture and hydrogen regeneration) while offering synthetic enhanced compatibility with the current membrane manufacturing processes. The membranes demonstrate a CO 2 and H 2 permeability of 2494 and 2932 Barrers, respectively, with a CO 2 /CH 4 , H 2 /CH 4 , and H 2 /N 2 selectivity of 29.3, 34.4, and 23.8, respectively, considerably surpassing the current Robeson permeability-selectivity upper bounds. At a MOF loading of 55 wt%, the membranes display a record-high 16-fold enhancement of H 2 permeability comparing with the neat polymer. With mild membrane processing conditions (e.g., a heating temperature less than 80 °C) and a performance continuously exceeding Robeson upper bounds for over 5300 h, the membranes exhibit enhanced compatibility with stateof-the-art membrane manufacturing processes. This performance results from intimate interactions between the polymer and MOFs via extensive, direct hydrogen bonding. This design approach offers a new route to ultraproductive membrane materials for energy-efficient gas separations.

Enhanced CO2 Capture and Hydrogen Purification by Hydroxy Metal–Organic Framework/Polyimide Mixed Matrix Membranes

“…The carboxylic groups in the polymer form direct hydrogen bonds with the hydroxy groups in UiO‐66‐(OH) 2 , thereby promoting intimate interphase adhesion in the mixed matrices. These O−H−O hydrogen bonds are formed between the OH groups in UiO‐66‐(OH) 2 and the carboxylic groups in 6FDD polyimide, whereas in UiO‐66‐NH 2 /6FDD mixed membranes, O−H−N hydrogen bonds are formed . To our knowledge, this is the first report of mixed‐matrix membranes containing UiO‐66‐(OH) 2 nanoparticles with performance exceeding the present Robeson upper bounds for multiple gas separation applications, including CO 2 capture and hydrogen purification.…”

“…Mixed‐matrix membranes based on UiO‐66 and its derivatives have been reported with superior performance . We previously reported membranes based on amino‐functionalized UiO‐66 (i.e., UiO‐66‐NH 2 ) with dramatically improved gas permeability . To assess how functionalization of the ligands independently affects the properties of membranes, herein, we focus on another type of frameworks derived from UiO‐66 but with distinct pore functionalities from UiO‐66‐NH 2 .…”

Pyrazine-Fused Porous Graphitic Framework-Based Mixed Matrix Membranes for Enhanced Gas Separations

“…Preparation of MMMs. The 6FDD polyimide was synthesized using reported procedures in the literature 26 and dried at 100 °C under vacuum overnight. The polymer was dissolved in tetrahydrofuran (THF) to prepare a 5-10 wt% solution.…”

Imputation of Missing Gas Permeability Data for Polymer Membranes using Machine Learning

“…Membrane Database for PIMs [18,35,36] and polyimides [37][38][39][40][41][42]. Representative molecular structures of the PIMs and polyimides are shown in Fig.…”