Study of CO2 adsorption onto poly(1-vinylimidazole) using quartz crystal microbalance and density functional theory methods

Polymers were used widely for the CO2 separation from natural gas. Therefore, poly (1-vinylimidazole) (PVIm) was synthesized by free-radical polymerization in solution. PVIm was characterized using proton nuclear magnetic resonance ((HNMR)-H-1) and Fourier transform infrared (FT-IR) spectroscopy. The kinetics and thermodynamics of CO2 adsorption were studied at different pressures and temperatures using quartz crystal microbalance (QCM) and experimental data were fitted using the dual-mode model. The evaluated kinetics and thermodynamics parameters of CO2 adsorption reveal that CO2 adsorption has physisorption and exothermic nature. Density functional theory (DFT) studies were performed to evaluate the relative affinity of the n-VIm from 1 to 4 monomers for the interacting molecules of CO2. Adsorption energies were computed and larger energy of adsorption in tetra-VIm-CO2 complex was seen compared to other n-VIm-CO2 complexes. (C) 2019 Elsevier B.V. All rights reserved.