MgMOF-74 is a promising candidate for a variety of gas separation applications, e.g., carbon capture and natural gas sweetening due to its high CO 2  uptake capacity and its favorable selectivity toward CO 2 . Motivated by its promising properties, MgMOF-74 has been extensively studied both experimentally and computationally. Experimentally determined adsorption isotherms show an inflection at a loading of approximately one CO 2  molecule per magnesium ion due to strong adsorption sites close to the ions. It is a great challenge to accurately reproduce this behavior in molecular simulations. In this study, we explicitly consider polarization between the adsorbed CO 2  molecules and the framework of MgMOF-74 via the induced point dipole method. Back-polarization is neglected to achieve reasonable simulation times. To account for implicitly incorporated polarization, we rescale the Lennard–Jones energy parameters with respect to the atomic polarizabilities. A series of Monte Carlo simulations of CO 2  in MgMOF-74 is conducted. The computed CO 2  adsorption isotherm is in good agreement with experimental measurements and previous simulation results using a DFT-derived force field. This indicates that polarization is important for describing the adsorption of CO 2  in MgMOF-74. The direct inclusion of polarization will lead to force fields with better physical justification and transferability.
['Tim M. Becker', 'David Dubbeldam', 'Li-Chiang Lin', 'Thijs J. H. Vlugt']
Investigating polarization effects of CO 2 adsorption in MgMOF-74