ZIF‐8 Membrane Separation Performance Tuning by Vapor Phase Ligand Treatment. Issue 46 (30th September 2019)

• Record Type: Journal Article
• Authors: Eum, Kiwon; Hayashi, Mikio; De Mello, Matheus Dorneles; Xue, Feng; Kwon, Hyuk Taek; Tsapatsis, Michael
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 46(2019)
• Page Start: 16390
• Page End: 16394
• Publication Date: 2019-09-30
• Subjects: ligand-induced permselectivity -- membranes -- metal–organic frameworks -- vapor phase -- ZIF-8; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201909490
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Vapor phase ligand treatment (VPLT) of 2‐aminobenzimidazole (2abIm) for 2‐methylimidazole (2mIm) in ZIF‐8 membranes prepared by two different methods (LIPS: ligand induced permselectivation and RTD: rapid thermal deposition) results in a notable shift of the molecular level cut‐off to smaller molecules establishing selectivity improvements from ca. 1.8 to 5 for O2 /N2 ; 2.2 to 32 for CO2 /CH4 ; 2.4 to 24 for CO2 /N2 ; 4.8 to 140 for H2 /CH4 and 5.2 to 126 for H2 /N2 . Stable (based on a one‐week test) oxygen‐selective air separation performance at ambient temperature, 7 bar(a) feed, and 1 bar(a) sweep‐free permeate with a mixture separation factor of 4.5 and oxygen flux of 2.6×10 −3 mol m −2 s −1 is established. LIPS and RTD membranes exhibit fast and gradual evolution upon a 2abIm‐VPLT, respectively, reflecting differences in their thickness and microstructure. Functional reversibility is demonstrated by showing that the original permeation properties of the VPLT‐LIPS membranes can be recovered upon 2mIm‐VPLT. Abstract : Oxygen separation from air and other gas separations are enabled by a facile vapor phase ligand treatment method (VPLT) for the modification of ZIF membranes. The changes of permeation properties are reversible and can be gradual, allowing for performance tailored to applications.