Synthesis of porous polymer based solid amine adsorbent: Effect of pore size and amine loading on CO2 adsorption.

A series of porous polymers was synthesized by a suspension polymerization of divinylbenzene (DVB) and ethylene glycol dimethyl acrylate (EGDMA), which was further functionalized with polyethyleneimine (PEI) for CO2 capture. The results showed that the synthesized DVB and EGDMA (DE) copolymers were an effective support for loading PEI because of its larger pore size and specific surfaces area. It was found that DE (30, 10) loaded with 30wt% PEI exhibited a higher CO2 adsorption amount of 3.28mmol/g at 25°C under dry condition. The CO2 adsorption capacity would decline gradually as the temperature continuously raised, for the reaction between CO2 and amine groups was an exothermic reaction. The kinetics study showed that Avrami kinetic model could accurately describe the whole CO2 adsorption process, suggesting that both physical adsorption and chemical adsorption were involved with the CO2 adsorption process. The intraparticle diffusion and Boyd's film diffusion models were applied to investigate the CO2 diffusion mechanism, the intraparticle diffusion model could well distinguish the rate-limiting step during CO2 adsorption process. This solid amine adsorbent could be regenerated with nitrogen stream at 75°C, and it kept stable CO2 adsorption capacity after eight adsorption-desorption cycles. All these features indicated that this porous polymer based adsorbent has a high potential for CO2 capture and separation from flue gas.