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

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 C₂H₂/C₂H₄ selectivity and C₂H₂ capacity. Herein, by expanding mixed-metal organic frameworks (M'MOFs) structure with high C₂H₂/C₂H₄ selectivity, we report a pillar-layered MOF, {[Cd₅(MPCZ)₂(BDC)₃(NO₃)₂(H₂O)₄]·G}_n (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 C₂H₂/C₂H₄ selectivity than the most reported MOFs, especially more than 5 times higher than MOF-74 series while displaying great enhancement in the C₂H₂ 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.