Premium
ZIF‐8 Membrane Separation Performance Tuning by Vapor Phase Ligand Treatment
Author(s) -
Eum Kiwon,
Hayashi Mikio,
De Mello Matheus Dorneles,
Xue Feng,
Kwon Hyuk Taek,
Tsapatsis Michael
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201909490
Subject(s) - membrane , permeation , selectivity , ligand (biochemistry) , chemistry , oxygen , gas separation , analytical chemistry (journal) , phase (matter) , molecule , air separation , bar (unit) , chemical vapor deposition , chemical engineering , chromatography , organic chemistry , receptor , catalysis , biochemistry , physics , meteorology , engineering
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 O 2 /N 2 ; 2.2 to 32 for CO 2 /CH 4 ; 2.4 to 24 for CO 2 /N 2 ; 4.8 to 140 for H 2 /CH 4 and 5.2 to 126 for H 2 /N 2 . 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.