Metal-organic framework membrane process for high purity CO₂ production

Significance: Gas separation by metal-organic framework (MOF) membranes is an emerging research field. Their commercial application potential is, however, still rarely explored due in part to unsatisfied separation characteristics and difficulty in finding suitable applications. Herein, we report "sharp molecular sieving" properties of high quality isoreticular MOF-1 (IRMOF-1) membrane for CO₂ separation from dry, CO₂ enriched CO₂/CH₄, and CO₂/N₂ mixtures. The IRMOF-1 membranes exhibit CO₂/CH₄ and CO₂/N₂ separation factors of 328 and 410 with CO₂ permeance of 2.55 × 10^-7 and 2.06 × 10^-7 mol m^-2 s^-1 Pa^-1 at feed pressure of 505 kPa and 298 K, respectively. High grade CO₂ is efficiently produced from the industrial or lower grade CO₂ feed gas by this MOF membrane separation process. The demonstrated "sharp molecular sieving" properties of the MOF membranes and their potential application in production of value-added high purity CO₂ should bring new research and development interest in this field.