The interzeolite transformation of micronsized FAU zeolite to nanosized CHA zeolite via alkali treatment is presented. The impact of the selection of FAU zeolite starting material on the properties of the produced CHA zeolite was analyzed by XRD, ICP, SEM, TEM, N2 and CO2 adsorption, and in situ FT-IR. The analysis showed that the choice of starting FAU zeolite had a large impact on the chemical composition, size, morphology, and porosity of the produced CHA zeolite. The as prepared CHA samples show high capacity toward CO2 (4.26 mmol/g) and it was demonstrated that the chemisorbed vs. physisorbed CO2 was controlled by varying the amount of alkali cations in the CHA zeolite.