In this study, to enhance the adsorption of carbon dioxide (CO2), a nanozeolite (Nano-Z) was modified with Cu2+, Ni2+, Cd2+, Mn2+ and Co2+ by cation-exchange method. The adsorption capacity of CO2 in modified nanozeolites increases with increase in the meso-pore volume of Nano-Z through ion exchange by divalent cations with appropriate ion radius. The adsorption isotherms of CO2 are investigated by employing a volumetric measurement at two temperatures (25 °C and 100 °C) and a pressure range up to 20 bar. The highest CO2 adsorption was observed at both temperatures for Cd-exchanged Nano-Z. A hybrid composite of Cd-exchanged Nano-Z and amine modified multi-walled carbon nanotube (MWCNT) has been synthesized by hydrothermal method. Polyethylenimine (PEI) was chosen as the amine source in the preparation of amine-functionalized MWCNT. Amine functionalized Nano-Z/Cd exhibited improved adsorption capacity of CO2 by combination of physical and chemical adsorption. Scanning electron microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), X-Ray Diffraction (XRD), N2 adsorption/desorption isotherms and Fourier Transform Infrared (FT–IR) were used to characterize the resulting nanocomposites.