Highly durable ZIF-8 tubular membranes via precursor-assisted processing for propylene/propane separation

ZIF-8 membrane has been considered as a potential alternative to the traditional cryogenic distillation process for propylene/propane (C₃H₆/C₃H₈) separation. However, the scale-up preparation and stability of ZIF-8 membranes are limited by the weak binding strength between membrane and tubular support. Herein, we report a precursor-assisted processing method that featured strong binding strength at the interface of ZIF-8 membranes and tubular supports. ZIF-8 tubular membranes are then assembled into a membrane module with an effective membrane area of about 157 cm² for efficient C₃H₆/C₃H₈ separation. Reliable binding strength is achieved and maintained over 10 min sonication which results in remarkable operation stability over 30 days. The C₃H₆ permeance and separation factor of this membrane module reached 1.08 × 10⁻⁸ mol m⁻² s⁻¹ Pa⁻¹ and 55 at 60 °C and 0.7 MPa, with purity and productivity of 98.3% and 6.2 × 10⁻⁵ mol s⁻¹, respectively. The good repeatability and durability of the ZIF-8 tubular membrane module demonstrate its potential for further scale-up towards practical application.