Enhancement of CO₂ adsorption on polyethylenimine functionalized multiwalled carbon nanotubes/Cd-nanozeolite composites

چکیده مقاله

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. © 2018