Characterization of CPs/Ca-exchanged FAU- and LTA-type zeolite nanocomposites and their selectivity for CO2 and N2 adsorption

The objective of this study was to investigate the adsorption capacity and selectivity of CPs/Ca-exchanged FAU-and LTA-type zeolite composites for carbon dioxide (CO2), and nitrogen (N-2). The adsorption isotherms of CO2 and N-2 on the adsorbents were measured at 298, 323, and 348 K and with a pressure range of 0-5 bar by means of the volumetric adsorption method. Modification of zeolite using cation exchange technique was used to determine the effect of different cation on gas adsorption characteristics. Sodium cations originally present in NaX, NaY and NaA are exchanged with calcium cations. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), X-Ray Diffraction (XRD) and N-2 adsorption/desorption isotherms were used to characterize the structure of the prepared zeolites. The addition of conducting polymers (CPs), polythiophene (PTh) and polypyrrole (PPy), to Ca-exchanged zeolites can improve the adsorption capacities of the material and at the same time increase the selectivity of the composite. CPs/Ca-zeolite nanocomposites were prepared by adding CPs to the CaX, CaY and CaA with different weight percentages p% (p = 5, 10 and 15%). CaX/PTh-15 can be used to separate CO2 from N-2 due to its high adsorption selectivity for CO2 over N-2.