Molecular Simulation Insights into Acid Gas Interactions within Ni-based Fluorinated Square-Pillared MOF.

Abstract

The increasing prominence of metal-organic frameworks (MOFs) in gas separation technologies has sparked significant interest in their application in flue gas treatment. Nevertheless, the adsorption of acidic gases in MOFs presents significant challenges owing to their complex interactions with the framework. Our research explored the adsorption interactions of acidic gases and their mixtures with [Ni(1,4-pyrazine)₂(AlF₅)]ₙ (ALFFIVE-Ni-Pyr) while considering the flexibility of the framework. Using grand canonical Monte Carlo (GCMC) simulations, we evaluated guest-host interactions, focusing on gas loading, whereas molecular dynamics (MD) simulations highlighted the structural dynamics induced by guest molecules within the framework. Density Functional Theory (DFT) calculations further confirmed the interactions between acidic gases and the framework. Our results show a significantly higher adsorption capacity for SO₂ than for CO₂ and NO₂, particularly in gas mixtures, highlighting the adaptability of the framework and its superior performance for acidic gas separation. This study aims to contribute to advancements in gas separation processes and provide valuable insights into the optimization of MOFs for industrial applications.