Defect-dependent stability of highly propylene-selective zeolitic-imidazolate framework ZIF-8 membranes

• Published in: Journal of membrane science Vol. 529; pp. 105 - 113
• Main Authors: Lee, Moon Joo, Kwon, Hyuk Taek, Jeong, Hae-Kwon
• Format: Journal Article
• Language: English
• Published: 01.05.2017
• Subjects: artificial membranes; ligands; propane; propylene; sieving; topology
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2016.12.068

Membranes of ZIF-8, a prototypical zeolitic-imidazolate framework (ZIF) with a sodalite topology, have shown excellent propylene/propane separation performances based on molecular sieving mechanism. Although the long-term stability of ZIF-8 membranes is of critical importance for their practical applications, there are only a few studies reported on the subject. Here, we report the long-term binary propylene/propane performances of ZIF-8 membranes prepared by two distinctive synthesis methods. A series of characterizations was employed to explain how different synthetic protocols led to the formation of ZIF-8 membranes with different bulk defect densities and surface defects, thereby affecting the long-term membrane stability. Finally, a post-synthetic ligand treatment is proposed as an effective means to mitigate the defects of ZIF-8 membranes, resulting in improved long-term separation performances.