Hegarty et al. (2023): Expanding the Library of Ions for Moisture-Swing Carbon Capture

John Hegarty, Benjamin Shindel, Daria Sukhareva, Michael L. Barsoum, Omar K. Farha, Vinayak Dravid IN: Environmental Science & Technology, https://doi.org/10.1021/acs.est.3c02543

This study builds on the promising moisture-swing modality for direct air capture of carbon dioxide by investigating the use of several new anions─orthosilicate, borate, pyrophosphate, tripolyphosphate, and dibasic phosphate─that when introduced into ion-exchange resins allow for the cyclable capture of CO₂ under dry conditions and its release under wet conditions. These ions, as well as many others that failed to show moisture-swing performance, are tested and directly compared thermodynamically and kinetically to understand their differences. This includes the use of analytical approaches new to the carbon capture field, such as the correlation of adsorption isotherms to moisture-swing performance, the use of phase lag kinetics, the examination of the humidity-carbon capture hysteresis of the sorbents, and the precise quantification of ion loading using inductively coupled plasma–optical emission spectroscopy.

LINK