(566f) Characterization of Calf-20: A Water Stable Metal-Organic Framework for Humid Post-Combustion CO2 Capture

Calgary Framework-20 (CALF-20) is a water stable MOF with a unique potential for post-combustion CO₂ capture. In this study, the competitive adsorption of (CO₂ + N₂) and (CO₂ + H₂O) on CALF-20 was examined by dynamic column breakthrough (DCB) experiments. The single component isotherms of CO₂ were measured from 22°C to 100°C and 0 bar to 5 bar using volumetric and gravimetric methods. Dual-site Langmuir (DSL) isotherm model was employed to fit CO₂ equilibrium data. CO₂+N₂ competitive measurements were performed using DCB and were well-characterized by the DSL isotherm. The H₂O adsorption isotherms were measured up to 80%RH in the temperature range of 22°C to 100°C. At low temperatures, the H₂O isotherm showed an inflection point, indicating very low water adsorption at low RH values, a characteristic that can be very advantageous for CO₂ capture. The Quadratic-Langmuir isotherm model was applied to describe the H₂O equilibrium data. H₂O dynamic column breakthrough (DCB) experiments were performed at a variety of RH values and the breakthrough curves demonstrated a variety of shapes reflecting the complexity of the isotherm. To measure the CO₂ and H₂O competitive loadings, two components (CO₂/H₂O) DCB experiments were studied at various RH (12% to 90%). The results indicated that under the presence of CO₂, H₂O broke through 20 times faster than the pure H₂O at 45% of RH. All single component CO₂ and H₂O breakthrough profiles and binary CO₂/H₂O breakthrough profiles were simulated using a built in-house MATLAB simulator. A good agreement between the experiments and simulations were obtained. The potential of using this material for vacuum swing adsorption (VSA) separation is also explored using numerical simulations