Experimental and numerical study of SO₂ removal from a CO₂/SO₂ gas mixture in a Cu-BTC metal organic framework

The mechanism of SO₂ removal from a CO₂/SO₂ gas mixture in a copper benzene-1, 3, 5-tricarboxylate (Cu-BTC) material is investigated at the molecular level by the grand canonical Monte Carlo method. The effects of seven kinds of force-field relationships among CO₂, SO₂ and Cu-BTC on the selectivity for a SO₂/CO₂ gas mixture at different temperatures are studied in detail. The accuracy of the simulation model is validated by the experimental data. The results show that more SO₂ molecules are adsorbed than CO₂, and the electrostatic interactions involving SO₂ are more sensitive to temperature than CO₂ is. The multilayer desorption for SO₂ and CO₂ occurs in large-square channels. The effect of the electrostatic interactions involving SO₂ is stronger than the interactions of CO₂. The forms of CO₂ and SO₂ adsorption in Cu-BTC with electrostatic interactions are Cu²⁺∙∙∙O[dbnd]C[dbnd]O and Cu²⁺∙∙∙O[dbnd]S[dbnd]O, respectively.