(244c) Facile Defect Engineering to Tailor Porous Coordination Polymers for Energy-Efficient Gas Separation

Membrane-based separation technology, a pressure-driven process, is more energy efficient than thermally-driven separation processes because it does not involve a phase change during separation. Zeolitic imidazolate frameworks (ZIFs) are attractive porous coordination polymers for gas separation composed of tetrahedrally-coordinated transition metal ions and imidazole organic ligands. They can be incorporated into a polymer matrix in the form of dispersed nanofillers, called mixed matrix membranes (MMMs), to provide potential scalability and superior molecular size-sieving ability. Recently, our group reported a new facile method of fabricating highly processable ZIF nanofillers, a so-called defect engineering approach, by using monodentate alkylamine modulators. It effectively suppresses the formation of non-selective interfacial voids around nanofillers in MMM and enhances the molecular sieving ability of ZIF-8 for C₃H₆/C₃H₈ separation. In addition, it can be extended to different gas separations, including CO₂/N₂ (or CO₂/CH₄) and C₂H₄/C₂H₆ separations, via either post-synthetic modification (PSM) or in-situ solution-based synthesis. In this talk, I will discuss engineering the desired molecular structure of ZIF nanofillers via defect engineering for gas separation as well as transforming a flat sheet MMM into a hollow fiber configuration.