Adsorption and separation of hexane isomers in metal-organic frameworks (MOFs): A computational study

Density functional theory (DFT) calculations and molecular simulation methods were combined to investigate the adsorption behaviors of two kinds of MOF materials: ZIFs and UiO-66-R. The factors affecting the adsorption performance were analyzed and the MOF materials with excellent adsorption performance were screened out. It is found that the differences of organic ligands affect the electronic properties and steric hindrance of the materials, thus significantly affecting the adsorption selectivity and adsorption capacity. The calculation results show that ZIF-78 and ZIF-81 have the ability to preferentially separate n-hexane from a mixture of C6 isomers, and the selectivity factor of 3MP over nHEX is 6; UiO-66-NH2 and UiO-66-OH have the ability to preferentially separate the di-branched alkanes in the adsorption separation of the mixed components, and the selectivity factor of 22DMB over nHEX is 15.