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

Abstract The search for adsorbents for flue gas desulfurization processes is a current interest. For the first time, a comparative experimental study of SO₂ adsorption by porous materials including the prototypical metal–organic frameworks NH₂‐MIL‐101(Cr), Basolite F300 (Fe‐1,3,5‐BTC), HKUST‐1 (Cu‐BTC), the zeolitic imidazolate frameworks (ZIF)‐8, ZIF‐67, the alumosilicate Zeolite Y, the silicoaluminumphosphate (SAPO)‐34, Silica gel 60, the covalent triazine framework (CTF)‐1, and the active carbon Ketjenblack is carried out. Microporous materials with pore sizes in the range of 4–8 Å or with nitrogen heterocycles are found to be optimal for SO₂ uptake in the low‐pressure range. The SO₂ uptake capacity at 1 bar correlates with the Brunauer‐Emmett‐Teller‐surface area and pore volume rather independently of the surface microstructure. Zeolite Y and SAPO‐34 are stable toward humid SO₂. The materials Zeolite Y and CTF‐1(600) show the most promising SO₂/CO₂ selectivity results with an ideal adsorbed solution theory selectivity in the range of 265–149 and 63–43 with a mole fraction of 0.01–0.5 SO₂, respectively, at 293 K and 1 bar.