Pore chemistry and geometry control in a metal azolate framework for one-step ethylene purification from quinary gas mixture

In the petrochemical industry, obtaining polymer-grade ethylene from complex light-hydrocarbon mixtures by one-step separation is important and challenging. Here, we successfully prepared the Metal-Azolate Framework 7 (MAF-7) with pore chemistry and geometry control to realize the one-step separation of ethylene from cracking gas with up to quinary gas mixtures (propane/propylene/ethane/ethylene/acetylene). Based on the tailor-made pore environment, MAF-7 exhibited better selective adsorption of propane, propylene, ethane and acetylene than ethylene, and the adsorption ratios of ethane/ethylene and propylene/ethylene are as high as 1.49 and 2.81, respectively. The pore geometry design of MAF-7 leads to the unique weak binding affinity and adsorption site for ethylene molecules, which is clearly proved by Grand Canonical Monte Carlo theoretical calculations. The breakthrough experiments show that ethylene can be directly obtained from binary, ternary, and quinary gas mixtures. These comprehensive properties show that MAF-7 is expected to achieve one-step purification of ethylene in complex light hydrocarbon mixtures.