Amine functionalized benzene based hypercrosslinked polymer as an adsorbent for CO2/N2 adsorption

Abstract

In this work, benzene based hypercrosslinked polymer (HCP) as an adsorbent was modified using amine group to enhance CO₂ uptake capability and selectivity. Based on BET analysis result, the HCP and the modified HCP provide surface area of 806 (m² g⁻¹) and micropore volume of 453 (m² g⁻¹) and 0.19 (cm³ g⁻¹) and 0.14 (cm³ g⁻¹), respectively. The CO₂ and N₂ gases adsorption were performed in a laboratory scale reactor at a temperature between 298 and 328 K and pressure up to 9 bar. The experimental data were evaluated using isotherm, kinetic and thermodynamic models to identify the absorbent behavior. The maximum CO₂ adsorption capacity at 298 K and 9 bar was obtained 301.67 (mg g⁻¹) for HCP and 414.41 (mg g⁻¹) for amine modified HCP. The CO₂ adsorption thermodynamic parameters assessment including enthalpy changes, entropy changes, and Gibbs free energy changes at 298 K were resulted − 14.852 (kJ mol⁻¹), − 0.024 (kJ mol⁻¹ K⁻¹), − 7.597 (kJ mol⁻¹) for HCP and − 17.498 (kJ mol⁻¹), − 0.029(kJ mol⁻¹ K⁻¹), − 8.9 (kJ mol⁻¹) for amine functionalized HCP, respectively. Finally, the selectivity of the samples were calculated at a CO₂/N₂ composition of 15:85 (v/v) and 43% enhancement in adsorption selectivity at 298 K was obtained for amine modified HCP.