Intercalation of CO(2) Selected by Type of Interlayer Cation in Dried Synthetic Hectorite

[Image: see text] Clay minerals are abundant in caprock formations for anthropogenic storage sites for CO(2), and they are potential capture materials for CO(2) postcombustion sequestration. We investigate the response to CO(2) exposure of dried fluorohectorite clay intercalated with Li(+), Na(+), Cs(+), Ca(2+), and Ba(2+). By in situ powder X-ray diffraction, we demonstrate that fluorohectorite with Na(+), Cs(+), Ca(2+), or Ba(2+) does not swell in response to CO(2) and that Li-fluorohectorite does swell. A linear uptake response is observed for Li-fluorohectorite by gravimetric adsorption, and we relate the adsorption to tightly bound residual water, which exposes adsorption sites within the interlayer. The experimental results are supported by DFT calculations.