High and reversible SO₂ capture by a chemically stable Cr(iii)-based MOF

Abstract

MIL-101(Cr)-4F(1%) shows a high uptake and high chemical stability to dry and humid SO2 and a remarkable cyclability. In situ DRIF spectroscopy upon the adsorption of CO identified the preferential adsorption sites for this MOF material.

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

“…[ 71 ] This is in agreement with a smaller enthalpy of adsorption near zero coverage, Δ H 0 ads = −36 kJ mol −1 for NH 2 ‐MIL‐101(Cr) (Figure S35, Supporting Information) than Δ H 0 ads = −54 kJ mol −1 for MIL‐101(Cr)4‐F. [ 71 ]…”

“…recently investigated SO 2 adsorption in the fluorinated MIL‐101(Cr)4‐F which shows a roughly similar isotherm shape to the isoreticular amino‐functionalized frameworks but with slightly higher SO 2 adsorption capacity with uptakes of 4.6 and 18.4 mmol g −1 at 0.1 and 1 bar, respectively, at 298 K and features exceptional stability against SO 2 . [ 71 ] This is in agreement with a smaller enthalpy of adsorption near zero coverage, Δ H 0 ads = −36 kJ mol −1 for NH 2 ‐MIL‐101(Cr) (Figure S35, Supporting Information) than Δ H 0 ads = −54 kJ mol −1 for MIL‐101(Cr)4‐F. [ 71 ]…”

“…We note that the parent MOF to NH 2 ‐MIL‐101(Cr), namely MIL‐101(Cr) is also not stable toward SO 2 which was explained by its comparatively hydrophilic nature. [ 71 ] We suggest that both NH 2 ‐MIL‐101(Cr) and Basolite F300 are unstable because the SO 2 can interact with the metal‐aqua and hydroxido ligand M‐OH 2 and M‐OH (Figure S1, Supporting Information), which are still present in both metal‐cluster secondary building units (SBUs) after activation at 120 °C. Such an interaction can form sulfurous acid or hydrogen sulfite which may break the metal‐carboxylate bonds with formation of metal‐sulfite and the conjugated acid of the ligand.…”

SO2 Capture Using Porous Organic Cages

“…The highest SO2 capture was achieved with 6FT-RCC3, reaching a maximum uptake of 13.68 mmol g -1 (Fig. 2), this uptake is only behind the reported benchmark MOFs such as MOF-177, [36a] MIL-101(Cr) 4F(1%), [21] or MFM-170 [44c] (25.7, 18.4 and 17.5 mmol g -1 , respectively). It is worth noting that the BET surface area of abovementioned three MOFs all exceeds 2000 m 2 g -1 , while for 6FT-RCC3 is 396 m 2 g -1 .…”

A Robust and Biocompatible Bismuth Ellagate MOF Synthesized Under Green Ambient Conditions

“…The resulting SO 2 isotherm shows a total uptake of 2.2 mmol g –1 ( Figure S21 ). Although this value is considerably lower than the uptake of other MOFs, 70 , 72 , 77 , 78 the stability of SU-101 upon adsorption–desorption cycling was investigated and structural integrity after both dry and humid SO 2 sorption was confirmed by PXRD ( Figures S25 and S27 ). Furthermore, the host–guest interaction between SU-101 and SO 2 was quantified, evaluating the isosteric heat of adsorption (Δ H ) for SO 2 at low coverage for SU-101 (estimated by fitting two adsorption isotherms at 303 and 308 K to a Clausius–Clapeyron equation, Figures S22 and S23 ).…”