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

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.