CO2 adsorption behavior and kinetics on polyethylenimine modified porous phenolic resin

The commercial porous phenolic resins (XAD-761) were selected as the support material for loading PEI to prepare solid amine adsorbents. The CO2 adsorption performances of the solid amine adsorbent was evaluated. The experimental results showed that when the PEI loading amount was 40 wt% on XAD-761, the CO2 adsorption amount could reach up to 3.85 mmol/g at 25 °C under dry condition. Meanwhile, the CO2 adsorption capacity declined as the temperature continuously raised, for the reaction between CO2 and amine groups was an exothermic reaction. The existence of water improved the utilization efficiency of amine groups on the adsorbents and finally lead to a great promoting of the CO2 adsorption amount. The kinetics study showed that Avrami kinetic model fitted better than the pseudo-first order and the pseudo-second order kinetic models for CO2 adsorption, suggesting that both physisorption and chemisorption were involved in the CO2 adsorption process of the prepared adsorbent. Moreover, the adsorbent exhibited good stability after five adsorption–desorption cycles. All these results indicated that this solid amine adsorbent has a high potential for CO2 capture and separation from flue gas.