Binary CO<sub>2</sub>/H<sub>2</sub>O Adsorption on CO<sub>2</sub> Capture Metal–Organic Frameworks CALF-20, Al-Fumarate and CAU-10-H Using Microscale Dynamic Column Breakthrough
Noëlie Constant, Gwyneth Liske, Shanmuk Srinivas Ravuru, Anjana Puliyanda, Véronique Pugnet, Alejandro Orsikowsky Sanchez, Sayali Ramdas Chavan, Philip L. Llewellyn, James A. Sawada, Arvind Rajendran
Abstract
This study reports the development of a quantitative microscale dynamic column breakthrough instrument to measure the competitive equilibrium loadings of CO 2 and H 2 O isotherms on small quantities (≈150 mg) of metal–organic framework (MOF) samples. The binary CO 2 and H 2 O equilibria were measured on CALF-20, Al-Fumarate and CAU-10-H, three MOFs of interest for postcombustion CO 2 capture at 30 °C and specifically since they show an S -shaped water isotherm. For Al-Fumarate and CAU-10-H, pure CO 2 and H 2 O competition was measured at 30 °C. For CALF-20, extensive mapping of the impact of CO 2 concentration and various water concentrations was performed at 30 °C. In all three MOFs, the CO 2 capacity is generally retained toward the left of the inflection point of the H 2 O isotherm. However CO 2 capacity drops toward the right of the inflection point, and the magnitude of the drop depends on the sharpness of the H 2 O isotherm. On the one hand, for Al-Fumarate and CAU-10-H the H 2 O isotherm was unaffected by CO 2 . On the other hand, for CALF-20, the presence of CO 2 impacts the H 2 O water isotherm, extending the relative humidity range over which the CO 2 capacity is retained. Using the ideal adsorbed solution theory to predict the binary equilibria revealed deviations from ideality for all three MOFs.