Metal-organic framework membranes with scale-like structure for efficient propylene/propane separation

The fabrication of metal-organic framework (MOF) membranes with high propylene/propane selectivity, high mechanical endurance and ease of scaling up always remains a challenge. Inspired by the ubiquitous biological wear-resistant structure, here we show ZIF-67 membranes with a tangential-normal interlaced structure (TN-ZIF-67) for one-step acquisition of polymer-grade propylene, which is endowed with the merits of intergranular defect elimination, partial ZIF-67 lattice flexibility restriction and anti-wear of the membrane surface. The TN-ZIF-67 membrane exhibits an optimal propylene/propane mixture separation factor of 221, and the separation performance remained unchanged after 1.5 years of storage or abrasion by repeated sanding. The distinctive membrane structure can be further scaled up on 4 mm-diameter tubular substrates. This work demonstrates a strategy to extend the rational design of defect-free, anti-wear MOF membranes with superior separation performance and stability that could fulfill future industrial applications. Easy-to-scale-up metal‒organic framework membranes with an anti-wear scale‒like structure and paralyzed lattices enable one-step acquisition of polymer‒grade propylene from a propylene/propane mixture.