SO₂ Capture and Separation: Adsorption Performance and Mechanism of the Amino-Modified UiO-67 Metal–Organic Framework

Sulfur dioxide (SO₂), a highly toxic and corrosive acidic gas, poses significant threats to both human health and the environment when emitted during fossil fuel combustion or various industrial processes. Therefore, the development of efficient governance materials is critical. Metal-organic frameworks (MOFs) exhibit remarkable potential for SO₂ adsorption, owing to their exceptionally specific surface area and tunable porous structures. In this study, a series of amino-functionalized UiO-67 materials were synthesized through the solvothermal method for SO₂ adsorption and separation. The successful introduction of amino groups was confirmed by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), etc. It is found that amino-functionalized UiO-67 shows significantly higher adsorption capacity of for SO₂ (12.5 cm³/g) at 298 K and 0.01 bar than that of the original UiO-67 (7.8 cm³/g). More importantly, it exhibits excellent selective separation performance in a mixed gas (SO₂/CO₂/N₂, 1213.8 s). It is due to the polar amino group in the skeleton as a hydrogen bond interaction site with SO₂, which can be proven by density functional theory (DFT) calculations. It provides a potential possibility for its application in industrial flue gas desulfurization and gas separation.