Pillar-Layered Metal-Organic Framework with Sieving Effect and Pore Space Partition for Effective Separation of Mixed Gas CH/CH.

The removal of acetylene from the industrial feed gas to purify the ethylene is an important and challenging issue. The adsorption-based separation is a more environmentally friendly and cost-effective method compared to the current removal approaches such as partial hydrogenation and solvent extraction, while facing the challenge of developing materials with high CH/CH selectivity and CH capacity. Herein, by expanding mixed-metal organic frameworks (M'MOFs) structure with high CH/CH selectivity, we report a pillar-layered MOF, {[Cd(MPCZ)(BDC)(NO)(HO)]·G} (MECS-5), which not only inherits the sieving effects of M'MOF series but also develops its own characteristic-the 2D layer with expanding space and the plane pore-partition group to "cover" it. MECS-5 shows higher ideal adsorption solution theory CH/CH selectivity than the most reported MOFs, especially more than 5 times higher than MOF-74 series while displaying great enhancement in the CH capacity, more than 2 times higher compared to the M'MOF. The column breakthrough experiment further proves the possibility of MECS-5a for real industrial ethylene purification.