Application of an amino-functionalized MIL-53(Al) MOF as an efficient, selective, and durable adsorbent for SO2 removal.

Sulfur dioxide (SO 2) is one of the acidic components found in the flue gas that can harm industrial facilities and the environment. SO 2 adsorption by metal-organic frameworks (MOFs) is an emerging method to effectively remove SO 2 in low concentrations from the gas mixtures. In this study, amino-functionalized MIL-53(Al), i.e., NH 2 -MIL-53(Al), was synthesized through the solvothermal method and examined for SO 2 adsorption at relatively moderate pressure and temperature (up to 2 bar, 25–80 ℃). According to the results of XRD, FT-IR, TGA, and DSC analysis, NH 2 -MIL-53(Al) demonstrated appropriate water, acid, and thermal stability. The SO 2 adsorption capacity of NH 2 -MIL-53(Al) was 5.21 mmol.g⁻¹ at T = 25 °C and P = 0.92 bar, significantly higher than its CO 2 adsorption capacity under similar conditions, demonstrating its high selectivity for adsorption of SO 2 relative to CO 2. Though the crystal structure of the tested MOF slightly changed after five adsorption/desorption cycles, its SO 2 adsorption capacity decreased only 6.64%, signifying its proper durability and regenerability under humid and acidic conditions. These features are promising to use NH 2 -MIL-53(Al) as a suitable adsorbent to selectively remove SO 2 from flue gas. [Display omitted] • A functionalized MOF (NH 2 -MIL-53(Al)) was examined for SO 2 adsorption. • NH 2 -MIL-53(Al) demonstrated appropriate water, acid, and thermal stability. • NH 2 -MIL-53(Al) showed excellent adsorption capacity at low SO 2 concentration. • NH 2 -MIL-53(Al) showed high selectivity to adsorb SO 2 over CO 2 at moderate P and T. • The MOF almost preserved its SO 2 adsorption capacity after 5 adsorption/desorption cycles. [ABSTRACT FROM AUTHOR]