High-Performance Cross-Linked Benzimidazole-and-Imine-Linked Polymer Membranes for Methanol/Methyl <i>tert</i> -Butyl Ether Separation

High-performance membrane materials serve as the cornerstone for advancing the industrial application of membrane separation technology and the development of membrane science theory. The swelling of polymer membranes by organic solvents results in a reduced separation performance, which limits the application of polymer materials in organic separation systems. A series of cross-linked benzimidazole-and-imine-linked polymer (BIILP) membranes with high separation performance were fabricated via interfacial polymerization accompanied by facile post-treatment. The membrane exhibited a total flux of 2.80 kg·m^-2·h^-1 and an exceptionally high separation factor of 4.80 × 10⁴ during the pervaporation (PV) separation of a 50 wt % methanol (MeOH)/methyl <i>tert</i>-butyl ether (MTBE) organic mixture at 50 °C. The membrane maintained its separation performance with only a marginal reduction after a 120 h PV stability test. The outstanding separation performance and high stability position BIILP membranes as strong candidates for scalable production and industrial application among polymer membranes.