Adsorption separation of acetylene and ethylene in a highly thermostable microporous metal-organic framework

A magnesium-based metal-organic framework with high hydrothermal stability, Mg-CUK-1, was investigated for the adsorption separation of acetylene from ethylene. The synthesized MOF remained excellent thermostability even near 500 °C according to TGA results. Characterization techniques including FTIR, SEM, and PXRD were utilized to confirm the detailed structure and properties of the Mg-based MOF. It exhibited moderate adsorption capacities of C 2 H 2 (3.01 mmol/g at 100 kPa and 273 K). Moreover, it showed preferential adsorption of C 2 H 2 over C 2 H 4 with C 2 H 2 /C 2 H 4 adsorption selectivity over 3, outperforming some popular MOFs. Furthermore, the isosteric heat of C 2 H 2 (<21 kJ/mol) and C 2 H 4 (<18 kJ/mol) were extremely lower than those MOFs with open metal sites. From an industrial point of view, this MOF could be synthesized in absence of organic solvent, drastically reducing the risk of environmental pollution in the production process. Besides, such advantages as excellent hydrothermal stability, cheap and non-poisonous metal ion resource, high C 2 H 2 adsorption capacity, and low isosteric heat make the Mg-based MOF promising in practical application.