Acid-CatalyzedInterfacial Polymerization of a Benzimidazole-LinkedPolymer Membrane for Efficient H₂/CO₂ Separation

The development of cost-effective and energy-efficient membrane materials is of significant importance for the purification of hydrogen and the capture of carbon dioxide. Given the potential of benzimidazole-linked polymers (BILPs) for H₂/CO₂ separation, this study aimed to synthesize a novel BILP membrane material (BILP-x) through an acid-catalyzed interfacial polymerization strategy. The BILP-x membranes achieved an exceptional H₂ permeance of 176.6 GPU and a H₂/CO₂ selectivity of 12.3 at room temperature. Decreasing the BTA concentration can significantly increase the H₂ permeance to 987.6 GPU, while the H₂/CO₂ selectivity decreased to 8.0 at room temperature. In addition, the BILP-x membrane demonstrated exceptional long-term stability in H₂/CO₂ separation, maintaining its performance for up to 300 h under alternating temperatures of 373 and 423 K. Meanwhile, the molecular dynamics simulations verified that the addition of acid accelerated the diffusion rate of TP molecules in the interfacial polymerization reaction, resulting in the formation of denser membranes. The finding not only validates the promise of BILP-x membranes for H₂/CO₂ separation, but also opens up a new avenue for the development of high-performance membrane materials for a range of separation applications.