Simulation study on functional group‐modified Ni‐MOF‐74 for CH4/N2 adsorption separation

Abstract This study employs grand canonical Monte Carlo (GCMC) simulations to investigate the impact of functional group modifications (CH 3 , OH, NH 2 , and OLi) on the adsorption performance of CH 4 /N 2 on Ni‐MOF‐74. The results revealed that functional group modifications significantly increased the adsorption capacity of Ni‐MOF‐74 for both CH 4 and N 2 . The packed methyl groups in CH 3 ‐Ni‐MOF‐74 create an environment conducive to CH 4 , leading to the highest CH 4 adsorption capacity. The electrostatic potential distribution indicates that the strong electron‐donating effect introduced by the alkali metal Li results in the highest electrostatic potential gradient in Li‐O‐Ni‐MOF‐74, leading to the strongest adsorption of N 2 , this is unfavorable for CH 4 /N 2 separation. At 1500 kPa the selectivity order of adsorbents for mixed gases was as follows: CH 3 ‐Ni‐MOF‐74 > NH 2 ‐Ni‐MOF‐74 > OH‐Ni‐MOF‐74 > Ni‐MOF‐74 > Li‐O‐Ni‐MOF‐74. This study highlights that CH 3 ‐Ni‐MOF‐74 possesses optimal CH 4 selectivity and adsorption performance. Given the current lack of research on functionalized MOF‐74 for the separation of CH 4 and N 2 , the findings of this study will serve as a theoretical guide and provide references for the applications of CH 4 adsorption and CH 4 /N 2 separation.