Pure silica CHA type zeolite (Si-CHA) was used in a high pressure swing adsorption for CO2 separation in the presence of water. The effective CO2 adsorption capacity was much higher than that of zeolite 13X, and was not influenced by coexisting water. The breakthrough curve gave an effective CO2 adsorption capacity of 3.1 mol kg−1 and CO2–N2 selectivity of >31.
