Steam Isotherms, CO₂/H₂O Mixed-Gas Isotherms, and Single-Component CO₂ and H₂O Diffusion Rates in CALF-20

Abstract

has emerged as a metal−organic framework (MOF) that is steam-stable and exhibits selective CO 2 physisorption over water vapor, which makes it a candidate for industrial-scale CO 2 capture from flue gases. In this work, multicomponent CO 2 /H 2 O adsorption data show that the α-to-β phase transformation has little impact on the multicomponent CO 2 adsorption capacity of CALF-20. Also, H 2 O isotherms up to 175 °C reveal only limited changes in the water capacity as temperature increases above 45 °C. CO 2 and H 2 O single-component diffusion rates were measured via concentration swing frequency response. The results show that the diffusion rate of water through CALF-20 is similar to that of water diffusion in the highly water-permeable MOF-333, as well as BPL-activated carbon. The data provides key insight into the fundamental thermodynamic and mass transfer parameters that govern the separation of CO 2 and H 2 O using CALF-20 and provides quantified parameters that can be used to model adsorption systems based on CALF-20.