Grand canonical Monte Carlo simulation of the adsorption and separation of carbon dioxide and methane using functionalized Mg-MOF-74

Grand canonical Monte Carlo (GCMC) simulations were used to analyse the effect of-O-Li,-NH2,-SH,-F,-COOH, and-NO2 functional groups on the adsorption and separation of pure CO2 and a mixture of CO2 and CH4. The metal-organic framework (MOF) skeleton was structurally optimized using the Forcite and Dmol3 modules. First, the GCMC method was employed to simulate the adsorption of pure CO2 by functionalized Mg-MOF-74 at 298 K and 10-3000 kPa. The results illustrated that-O-Li,-NH2, and-SH groups increased the CO2 adsorption below 101 kPa and followed the order Li-O-Mg-MOF-74 > NH2-Mg-MOF-74 > SH-Mg-MOF-74. When the pressure was >101 kPa, the adsorption capacity of Mg-MOF-74 was higher than that of functionalized Mg-MOF-74. Then, the adsorption capacity and selectivity of functionalized Mg-MOF-74 in the CO2/CH4 mixture were investigated at 298 K and 10- 3000 kPa. The results showed that the introduction of-O-Li,-NH2, and-SH groups increased the CO2 selectivity of Mg-MOF-74 within the range of 10-1440 kPa and followed the order Li-O-Mg-MOF-74 > NH2-Mg-MOF-74 > SH-Mg-MOF-74. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).