Conformation‐Controlled Molecular Sieving Effects for Membrane‐Based Propylene/Propane Separation

• Published in: Advanced materials (Weinheim) Vol. 31; no. 14; pp. e1807513 - n/a
• Main Authors: Liu, Yang, Chen, Zhijie, Liu, Gongping, Belmabkhout, Youssef, Adil, Karim, Eddaoudi, Mohamed, Koros, William
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 05.04.2019
• Subjects: Apertures; Fillers; Materials science; Membranes; Metal-organic frameworks; mixed‐matrix membranes; MOFs; Molecular sieves; Propane; Propylene; propylene/propane; Selectivity; Separation; Zirconium; propylene/propane; mixed-matrix membranes; MOFs; separation
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201807513

Membrane‐based separation is poised to reduce the operation cost of propylene/propane separation; however, identifying a suitable molecular sieve for membrane development is still an ongoing challenge. Here, the successful identification and use of a metal–organic framework (MOF) material as fillers, namely, the Zr‐fum‐fcu‐MOF possessing an optimal contracted triangular pore‐aperture driving the efficient diffusive separation of propylene from propane in mixed‐matrix membranes are reported. It is demonstrated that the fabricated hybrid membranes display a high propylene/propane separation performance, far beyond the current trade‐off limit of polymer membranes with excellent properties under industrial conditions. Most importantly, the mechanism behind the exceptional high propylene/propane selectivity is delineated by exploring theoretically the efficiency of sieving of different conformers of propane through the hypothesized triangular rigid pore‐aperture of Zr‐fum‐fcu‐MOF. The traditional understanding of the molecular sieving effect is refined by considering the CC single bond rotation in C3H6 and C3H8 molecules. Zr‐fum‐fcu‐MOF with trefoil‐like pore‐aperture is therefore rationally selected as efficient C3H6/C3H8 fillers in mixed matrix membranes (MMMs). The fabricated MMMs shows excellent C3H6/C3H8 separation performance, far beyond the trade‐off of polymer membranes.