Controllable synthesis of ZIF-8 interlocked membranes for propylene/propane separation

ZIF-8 membrane has received extensive attention recently for propylene/propane (C₃H₆/C₃H₈) separation. However, the weak long-term durability and scalability/reproducibility of ZIF-8 membranes are limited by the poor adhesion between the membrane and the curved support. A successful preparation of high adhesion ZIF-8 membranes on the curved support remains a challenge. The ZIF-8 membrane with interlocked architecture was expected to exhibit more reliable durability due to the strengthened crystal boundaries. Herein, we synthesized uniform ZnO nanoparticles in the inner upper layer of the ceramic tube support by combining slip-casting and vacuum drying methods. The dense ZIF-8 interlocked membranes were further prepared by the ligand activation processing for efficient C₃H₆/C₃H₈ separation. The interlocked ZIF-8 membrane exhibited reliable long-term durability over 54 h under different operation conditions. Furthermore, the C₃H₆ permeance and separation factor of the membrane reached 8 × 10⁻⁹ mol m⁻² s⁻¹ Pa⁻¹ and 130 at 25 °C and feed pressure of 1 bar, respectively, comparable to that of previously reported other supported ZIF-8 membranes. Therefore, the ZIF-8 interlocked membranes are promising for practical industrial gas separation.