Kinetic-Sieving of Carbon Dioxide from Acetylene through a Novel Sulfonic Ultramicroporous Material

The engineering and tailoring of porous materials to realize the precise discrimination of CO₂ and C₂ H₂ , with almost identical kinetic diameters, is a challenging task. We herein report the first example of the kinetic-sieving of relatively larger molecule of C₂ H₂ from CO₂ by a novel sulfonic anion-pillared hybrid ultramicroporous materials of ZU-610a. Specifically, ZU-610 constructed from copper(II), isonicotinic acid and 1,2-ethanedisulfonic acid is synthesized and shows the preferential affinity for C₂ H₂ over CO₂ . After the post-synthetic heat treatment of ZU-610, ZU-610a with a contracted aperture is obtained. Interestingly, the C₂ H₂ -selctive ZU-610 was reversed to the CO₂ -selective ZU-610a. High purity C₂ H₂ (>99.5 %) could be directly obtained from the dynamic breakthrough experiments on an equimolar C₂ H₂ /CO₂ mixture at 298 K. This study provides guidance for the design of adsorbents aimed at separation systems with similar kinetic diameter.