Metal–Organic Frameworks with Potential Application for SO₂ Separation and Flue Gas Desulfurization

Abstract

Sulfur dioxide (SO2) is an acidic and toxic gas and its emission from utilizing energy from fossil fuels or in industrial processes harms human health and environment. Therefore, it is of great interest to find new materials for SO2 sorption to improve classic flue gas desulfurization. In this work, we present SO2 sorption studies for the three different metal–organic frameworks MOF-177, NH2-MIL-125­(Ti), and MIL-160. MOF-177 revealed a new record high SO2 uptake (25.7 mmol·g–1 at 293 K and 1 bar). Both NH2-MIL-125­(Ti) and MIL-160 show particular high SO2 uptakes at low pressures (p < 0.01 bar) and thus are interesting candidates for the removal of remaining SO2 traces below 500 ppm from flue gas mixtures. The aluminum furandicarboxylate MOF MIL-160 is the most promising material, especially under application-orientated conditions, and features excellent ideal adsorbed solution theory selectivities (124–128 at 293 K, 1 bar; 79–95 at 353 K, 1 bar) and breakthrough performance with high onset time, combined with high stability under both humid and dry SO2 exposure. The outstanding sorption capability of MIL-160 could be explained by DFT simulation calculations and matching heat of adsorption for the binding sites Ofuran···SSO2 and OHAl‑chain···OSO2 (both ∼40 kJ·mol–1) and Ofuran/carboxylate···SSO2 (∼55–60 kJ·mol–1).

Comparative Evaluation of Different MOF and Non‐MOF Porous Materials for SO2 Adsorption and Separation Showing the Importance of Small Pore Diameters for Low‐Pressure Uptake

“…Currently, the SO 2 adsorption with metal–organic frameworks (MOFs) experiences high interest. [ 11–27 ] Metal–organic frameworks are typically microporous metal‐ligand coordination networks with uniform porosity, low density, and high tunability through the organic linker, that is, the metal‐bridging ligand. [ 28 ] MOFs are actively studied in the role of adsorbents (particularly N 2 , H 2 , CO 2 , CH 4 , etc.)…”

Adsorbents for Noxious Gas Sequestration: State of the Art

“…MOFs, polymers, AC, and membrane have also been reported to sequester noxious gases such as SO 2 , NH 3 and H 2 S, considerably at precombustion and post-combustion conditions, despite the chemical stability challenges posed by compounds such as SO 2 and H 2 S to adsorbents. For SO 2 capture, MOF compounds such as MOF-3 [56], NH 2 -MIL-125 (Ti) [144], MFM-300 (Sc) [55] and MIL-160 [144], MOC-1 and MOC-3 [54] had better adsorption capacity at post-combustion conditions at ambient temperatures, as shown in Table 4. Unfortunately, none of these compounds were investigated at temperatures consistent with Flue Gas Desulfurization (FGD) systems.…”

Choline-Based Ionic Liquids-Incorporated IRMOF-1 for H2S/CH4 Capture: Insight from Molecular Dynamics Simulation

“…MOF appears as one of the best materials to be used as the supporting absorber due to its intriguing features, such as high surface contact, high porosity [22][23][24][25][26] and pore volume, large gas storage, and high tunability [27][28][29], making it a suitable material for gas separation and adsorption. It is widely used in gas separation and storage [30][31][32], ion exchange [33,34], catalysis, and conductivity [35,36].…”