A Chemically Robust Microporous Zn-MOF for C₂H₂ Separation from CO₂ and Industrially Relevant Four Component Gas Mixtures

The separation and purification of acetylene from the light hydrocarbon gas mixtures is considered as one of the most industrially challenging task for the production of fine chemicals. Though metal-organic frameworks (MOFs) are promising candidates for such separation and offer a cost and energy-efficient pathway, achieving the trade-off between sorption capacity and separation selectivity along with framework robustness is a daunting task and demands effective design. Herein, a new 3D chemically stable MOF, IITKGP-24 (stable over a wide range of aqueous pH solution, pH = 2-12) is developed, displaying excellent separation selectivity of 13.9 for C₂H₂/CO₂ (50:50) even at ambient conditions and maintained a trade-off between sorption capacity and separation selectivity. Most importantly, the breakthrough performance analysis under the industrially relevant gas mixture composition revealed that the developed framework possesses excellent separation of acetylene from not only C₂H₂/CO₂ (50:50) gas mixtures but also from the quaternary C₂H₂/C₂H₄/C₂H₆/CO₂ (25:25:25:25) feed gas streams. Separation of C₂H₂ from such a four component gas mixture by MOFs is unexplored. The exceptional framework robustness, high C₂H₂/CO₂ uptake ratio, low heat of adsorption, and excellent recyclability with easy regenerability made the developed framework promising candidate toward this challenging separation.