Adsorption behavior and kinetics of CO2 on amine-functionalized hyper-crosslinked polymer

A hyper-crosslinked polymer (XAD-4-pc) was developed by modifying the commercial polystyrene resin (XAD-4) through a Friedel–Crafts reaction, followed by impregnation with polyethyleneimine (PEI) for CO₂ capture. The physicochemical properties of the as-synthesized adsorbents were analyzed by different characterization techniques, and the adsorption behavior of CO₂ on these adsorbents was evaluated in a self-assembled adsorption setup with gas chromatography. Experimental results found that the Brunauer–Emmett–Teller surface area and pore volume of XAD-4-pc were significantly higher than that of XAD-4, which was favorable to the improvement of PEI loading and CO₂ adsorption. The maximum CO₂ uptake for PEI-functionalized XAD-4-pc was 3.24 mmol g^?1 at 25 °C. The adsorption isotherm of CO₂ on the adsorbent was well described by the Langmuir equation, and the kinetics data could be accurately described by Avrami model over the entire adsorption range. The diffusion mechanism study showed that the film diffusion and intraparticle diffusion were mainly the rate-limiting steps. Moreover, this adsorbent could be well regenerated at relatively low temperature and exhibited stable regenerability after five adsorption-regeneration cycles, showing its high potential for the capture of CO₂ from flue gases. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48479.