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.
Keywords: C2H2/C2H4; metal−organic frameworks; pillar-layered Cd-MOF; pore space partition; selective adsorption; sieving effect.