Predicting Mixture Coadsorption in Soft Porous Crystals: Experimental and Theoretical Study of CO2/CH4 in MIL-53(Al)

We present a synergistic experimental and theoretical study of CO2/CH4 mixture coadsorption in breathing metal–organic framework MIL-53(Al). Mixture adsorption experiments were performed and their results were analyzed by comparing them to predictions made from pure-component adsorption data using the Osmotic Framework Adsorption Solution Theory (OFAST). This analytical model, fully validated for the first time, was then used to predict coadsorption properties as a function of temperature, pressure, and mixture composition. The phase diagrams obtained show a surprising non-monotonic behavior.