A Computational Study of the Adsorptive Removal of H2S by MOF-199

Metal–organic framework material MOF-199 is a new type of adsorption material for removal toxic H2S. In this work, the effects of temperature and pressure on the performance of H2S adsorption in MOF-199 were studied by using the grand canonical Monte Carlo (GCMC) simulation; the interaction mechanism between framework atoms of MOF-199 and guest H2S molecules were further discussed through density functional theory (DFT) calculations. It is found that the MOF-199 adsorption capacity towards H2S decreases with increasing temperature and increases with increasing pressure. At low pressures, the frameworks containing the binding sites of copper dimers and trimesic acid are the main factor affecting the adsorption performance of MOF-199. While at high pressures, the free volume of MOF-199 contributes to the adsorption capacity as well. The adsorptive interactions between H2S and the organic ligand are weak (>− 14.469 kJ/mol). When H2S adsorption on the Cu–Cu bridge, the binding energies of the modes where hydrogen is put inward of the copper dimer are generally smaller than that where hydrogen is outward, whereas the adsorption on the top of copper ion shows the smallest BEs value (<− 50 kJ/mol) due to its tendency of forming a saturated six-coordinated configuration.