Recent advances in microporous metal-organic frameworks as promising adsorbents for gas separation

Gas separation is a crucial process for the production of many highly valuable chemical feedstocks in the petrochemical industry. Traditional separation technologies, including cryogenic distillation, chemisorption, and solvent extraction, are energy-intensive or environmentally unfriendly. The development of new separation technologies with low energy consumption and high efficiency is of significant importance for adapting to the increasing industrial demands. Adsorptive gas separation based on solid porous adsorbents has made much progress over the past few decades, benefiting from low cost, high efficiency, and environment friendliness. In this regard, porous metal-organic frameworks (MOFs), as a novel class of crystalline porous materials featuring adjustable structures and finely tunable pore metrics, have shown great promise to address various gas separation challenges. Furthermore, the highly crystalline nature of MOFs endows this kind of material with a unique advantage, providing an in-depth understanding of the structure-property relationship, which is crucial and meaningful to guide the design of separating materials for gas separation. Herein, we summarize the main advancements achieved in the last five years of developing MOFs as physisorbents for various critical gas separations, including but not limited to the separation of light hydrocarbons, C2H2/CO2, and Xe/Kr, and CO2 capture, and the separation mechanisms are also highlighted in each section. Finally, some challenges and perspectives in the design of MOFs for gas separation and industrial applications are outlined.