Improving the CH4 adsorption property and the CO2/CH4 separation of IRMOF-3 by functionalizing the organic linker

Abstract

Grand Canonical Monte Carlo (GCMC) simulation combining with the ideal adsorbed Solution Theory (IAST) are employed to study the effect of functionality on the CH₄ adsorption property and CO₂/CH₄ selectivity of modified irmof-3 structures which include a diverse range of functional groups. The result shows that phenyl groups containing nitrogen (e.g. pyrazine, pyridine) and carboxyl group are able to increase the interaction energy between gas and mof, thereby increasing the gas adsorption capacity. In addition, transition metals can significantly enhance the CO₂/CH₄ selectivity. The straight-chain alkyl group and aniline groups just slightly improve the material property compared to other functional groups. We also note that materials with more than 50 percent of modification do not show a good performance at high pressure range (35–40 atm) due to its low porosity. We herein show that the functionalization of IRMOF-3 can remarkably improve the CH₄ uptake and CO₂/CH₄ separation; particularly, GCMC simulation is demonstrated as a beneficial tool to aid experimental chemists in designing new promising porous materials.