CO2 adsorption in nanosized RHO zeolites with different chemical compositions and crystallite sizes

In this work, nanosized RHO zeolite samples with different Si/Al ratios were synthetized and tested for CO2 adsorption by combining in situ IR spectroscopy and in situ X-ray powder diffraction using synchrotron radiation. The structural changes of the RHO nanosized zeolites, subjected to high temperature treatment (350 °C) and CO2 adsorption (1 and 5 bar), studied by high-resolution X ray powder diffraction, indicated the presence of two phases with different cell parameters in both samples. The combination of the X-ray technique with IR allowed evaluation of the CO2 adsorption capacity of the samples and their adsorption dynamic. The results indicated that the CO2 adsorption capacity is mainly related to the sodium content in the nanosized RHO crystals. The performed adsorption experiments showed that 1 bar CO2 is sufficient to saturate the RHO samples at room temperature, and no change in the CO2 adsorption capacity at 5 bar was observed.