Pressure-resistant propylene/propane separation by ZIF-8 membranes decorated with polyether-block-amide copolymer

ZIF-8 is an ideal membrane material for C 3 H 6 /C 3 H 8 separation. However, its inherent framework flexibility leads to structural changes under external pressure, impairing the C 3 H 6 /C 3 H 8 separation performance. In this work, ZIF-8 membranes were decorated with a low-cost polyether-block-amide copolymer, Pebax 2533. The copolymer, containing flexible PTMO segments and rigid PA12 segments, enhanced the rigidity of the ZIF-8 framework through confinement effects and interfacial interactions. The resultant ZIF-8 P2533 membranes exhibit excellent pressure-resistant separation performance. As the transmembrane pressure was increased from 0 to 6 bar, the separation factor increased by 49%, from 152 to 227, while the C 3 H 6 flux reached 2.25 × 10 −3 mol·m −2 ·s −1 , outperforming most currently reported C 3 H 6 /C 3 H 8 separation membranes. This work demonstrates that Pebax 2533 post-modification significantly enhances the separation stability of ZIF-8 membranes under high-pressure conditions, highlighting their potential for practical C 3 H 6 /C 3 H 8 separation, although further enhancement of permeance is still desirable.