Improved H2/CO2 separation performance on mixed-linker ZIF-7 polycrystalline membranes. (31st December 2018)

• Record Type: Journal Article
• Authors: Chang, Hao; Wang, Yan; Xiang, Long; Liu, Donghui; Wang, Chongqing; Pan, Yichang
• Is Part Of: Chemical engineering science. Volume 192(2018)
• Page Start: 85
• Page End: 93
• Publication Date: 2018-12-31
• Subjects: Metal-organic frameworks -- MOF membranes -- ZIF-7 -- Gas separation -- Hydrogen separation; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2018.07.027
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: The ZIF-7-NH2 polycrystalline membranes were first prepared. The coating of Pebax®1657 layer effectively control the microstructure of membrane. Improved separation performance for H2 /CO2 mixture on ZIF-7 membrane was reported. ZIF-7-NH2 crystals exhibit higher hydrothermal stability than mono-ligand ZIF-7. Abstract: Membrane-based hydrogen purification has been considered to be a promising alternative because of its low energy consumption, ease of operation, and cost effectiveness. Amino-functionalized ZIF-7 (ZIF-7-NH2 ) is an attractive candidate for membrane gas separation due to the maintenance of pore-opening structure after total removal of guest molecules (DMF). In this work, ZIF-7-NH2 membrane with improved both H2 permeance and H2 /CO2 selectivity than reported mono-ligand ZIF-7 membrane was first prepared. Several activation process for ZIF-7-NH2 membranes to opening the pores were investigated. It was found that the coating of a Pebax®1657 layer on the surface of ZIF-7-NH2 membrane is crucial for preventing the formation of cracks during pore-activation procedure. The permeance of H2 and separation factor for H2 /CO2 binary mixtures were improved to ∼ 1 × 10 −7 mol/m 2 s Pa and ∼19, respectively. The separation performance was very close to the upper bound for inorganic microporous membranes. Furthermore, the improved hydrothermal stability on ZIF-7-NH2 materials endows the membrane is highly potential for hydrogen purification.