Privileged zeolitic sites for humid CO 2 adsorption: K + in double eight-membered rings.

Humid CO 2 adsorption in K + -exchanged zeolites featuring double-eight membered ring (D8R) structures results in CO 2 outcompeting and desorbing dimeric water under equilibrated conditions, which is not observed for either the H + -form of the same zeolites or larger-pore zeolites.