Current Perspectives and Mini Review on Zeolitic Imidazolate Framework-8 (ZIF-8) Membranes on Organic Substrates

Abstract

Zeolitic Imidazolate Framework (ZIF) membranes have been considered as promising membrane for gas separation processes due to their robustness and good separation capabilities. The separation of hydrogen (H2) from larger gases is one of their potential applications. Among the different types of ZIF, ZIF-8 is considered as potential candidates for H2 separation owing to its small aperture size and excellent chemical stability. In recent years, ZIF-8 membranes have been fabricated on both inorganic and polymeric substrates. The fabrication of the ZIF-8 layer on polymeric substrates is more challenging than its inorganic counterpart because of the incompatibility issue between organic substrates and ZIF-8. However, the flexible nature of polymeric substrates offers better mechanical stability at high pressure than inorganic substrates. The purpose of this mini-review is to present the state of the art and challenges of research on ZIF-8 membrane synthesis on different polymeric substrates. These challenges include the formation of cracks and defects due to compatibility issues and membrane stability at different operating conditions. Current research results showed excellent gas separation properties of ZIF-8 membranes on polymeric substrates that can surpass the trade-offline of gas permeability and selectivity.

The opportunity of membrane technology for hydrogen purification in the power to hydrogen (P2H) roadmap: a review

“…In a different approach, Liu et al used the ZnAl-LDHs as a buffer for connecting the zeolitic-imidazolate framework-8 (ZIF-8) seed layer onto the Al 2 O 3 support and the wellintergrown ZIF-8 membrane was formed during the secondary growth [120]. Recently, ZIF-8 is incorporated on hollow fibre membrane in a laboratory scale continuous process [124,125], which shows a promising signal for commercial scale application of MOF membranes in the future.…”

Structure and dynamics of a water/methanol mixture confined in zeolitic imidazolate framework ZIF-8 from atomistic simulations

“…Among ZIF materials, ZIF-8, which consists of Zn ions and 2-methylimidazolate with sodalite (SOD) topology, is undoubtedly the most extensively investigated ZIF. 18,19 Contradictory results on the water stability of ZIF-8 were reported in the literature. 16,20–23 While some early reports 16,20 suggested high water stability of ZIF-8 because there is no change in the X-ray diffraction (XRD) patterns of ZIF-8 crystalline powders after being placed in boiling water, an increasing number of studies demonstrated that ZIF-8 can partially degrade in aqueous solutions depending on the ZIF-8 to water mass ratio.…”

Synthesis and structural analysis of beta cobalt hydroxide (ß-CoOH) nanosheets derived from ZIF 67 metal-organic framework

“…The bonding in ZIF is a coordination bonding that is weaker than covalent bonding in the zeolites thus leading to a kinetically lesser stable bond. This lesser stability enables the substitution by other ligands [13].…”