Study on Adsorption Properties of Ammonium Exchanged Chabazite for CO2

Ammonium type chabazite (NH4CHA) and magnesium type chabazite (MgCHA) was prepared by hydrothermal synthesis and hydrothermal ion exchange. The structure and morphology of ion‐exchanged chabazite was characterized with various experimental techniques such as XRD, SEM, and ICP. The gas adsorption amount of chabazite decreases gradually with increase in temperature or decrease in pressure. The adsorption capacity of NH4CHA to CO2 was 3.33 mmol·g–1 at 273 K, and the saturated adsorption capacity of NH4CHA reached 3.88 mmol·g–1 under extreme pressure. The CO2 molecule was more likely to be adsorbed by all chabazite samples than the N2 molecule due to its linear molecular structure and greater molecular polarity. NH4CHA exhibited larger CO2/N2 selectivity, which first increased and then declined with the temperature decreasing, and reached the maximum value between 400 K to 450 K.