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.

WITHDRAWN: Zn(II) Metal-organic Framework Nanoparticles: Synthesis, Characterization and Application as Optical Biosensor for Prostate-Specific Antigen

“…On the other hand, the nanomaterials generally and metal-organic frameworks in nano-size-scale (MOF-NPs) especially have many advantages and auspicious properties like chemical and thermal stability, porosity, large surface area, highly magnetic, excellent adsorbent materials …., etc. [23][24][25][26][27][28][29][30][31][32]. Different excellent physicochemical properties of the MOF-NPs make these nanomaterials are very sensitive and selective tools for bonding to biological and organic molecules and can be simply interacted moreeffective than bulk state materials [33].…”

A Series of new Urea‐MOFs Obtained via Post‐synthetic Modification of NH2‐MIL‐101(Cr): SO2, CO2 and H2O Sorption

“…This confirms earlier results by Martínez-Ahumada et al that MIL-101(Cr) gradually loses its crystallinity and surface area after dry SO 2 sorption at 298 K. [28] Similarly, we found in a recent study that NH 2 -MIL-101(Cr) lost porosity after dry and especially after humid SO 2 exposure (Figure S14b, SI). [68] The instability of MIL-101(Cr) towards SO 2 was explained by its comparatively hydrophilic nature. [28] We suggest that both MIL-101(Cr) and NH 2 -MIL-101(Cr) are unstable because the SO 2 can interact with the chromium-aqua and -hydroxido ligand (CrÀ OH 2 and CrÀ OH) in the trinuclear secondary building unit (SBU) (Figure S1a Mounfield et al have confirmed the formation of bisulfite species and, together with theoretical simulations, suggested that the degradation of the MIL-125 framework proceeds by reaction with water and the dissociation of water or sulfurous acid.…”

Capture and Separation of SO2 Traces in Metal–Organic Frameworks via Pre‐Synthetic Pore Environment Tailoring by Methyl Groups

“…[31,32] In addition, it has been recently pointed out that small micropore diameters in the range of approximately 4to 8 could be advantageous for low-pressure SO 2 uptake. [33] MOFs with methyl-functionalized linkers could be agood candidate for tailoring micropore diameters to the optimal range and at the same time having moderate non-covalent van der Waals (vdW) interactions with SO 2 molecules for sufficient SO 2 affinity but still facile (desorption) regeneration. Methyl-functionalized MOFs have been shown to display enhanced CO 2 uptake affinity, [34,35] but were not explored for SO 2 sorption and separation to the best of our knowledge.W epropose that MOFs with an already feasible topology could be tuned in their pore diameter for an efficient SO 2 separation through methyl-functionalization.…”

“…The other one is polar amino groups in the framework as sites for hydrogen‐bonding interactions with SO 2 [31, 32] . In addition, it has been recently pointed out that small micropore diameters in the range of approximately 4 to 8 Å could be advantageous for low‐pressure SO 2 uptake [33] …”