Selective Dynamic CO2 Separations on Mg-MOF-74 at Low Pressures: A Detailed Comparison with 13X

This study investigates the potential of the well-known metal–organic framework (MOF) Mg-MOF-74 for low-pressure CO 2 separations under dynamic conditions. We developed a technique to make pellets of Mg-MOF-74 without large capacity loss and measured CO 2 and CH 4 isotherms on these pellets up to 40 bar in the temperature range of 293–338 K. Dynamic breakthrough separation experiments with mixtures of CO 2 and CH 4 on a column packed with Mg-MOF-74 pellets at 308 K and 1 bar indicated a higher CO 2 capacity and separation efficiency for the MOF with respect to the benchmark 13X zeolite. The MOF regains 81% of its original capacity when purging with helium at 308 K during 10 min and can be fully regenerated at 353 K, which indicates the facile desorption of CO 2 on this material. However, the performance of Mg-MOF-74 severely deteriorates upon long-term exposure to relevant impurities in CO 2 separations at low pressures such as water and oxygen.