Preparation and characterization of molecularly imprinted solid amine adsorbent for CO2 adsorption

Abstract

A molecularly imprinted solid amine adsorbent was successfully synthesized via a facile crosslinking reaction based on polyethyleneimine (PEI) as the skeleton, glycol diglycidyl ether (GDGE) as cross-linker and CO₂ molecules as template. FT-IR, FT-Raman, ¹³C NMR spectroscopy and TGA were employed to characterize the chemical structure and thermal stability of the solid amine adsorbent. The experimental results showed that the amine content of the molecularly imprinted polymer polyethyleneimine spheres (MIP-PEIs) could reach as high as 11.41 mmol g⁻¹, and the material exhibited a lower CO₂ diffusion resistance during CO₂ adsorption. The CO₂ adsorption capacity of MIP-PEIs (6.58 mmol g⁻¹) was higher than that of non-imprinted NIP-PEIs (5.87 mmol g⁻¹). The presence of water markedly increased the CO₂ adsorption capacity by promoting the chemical adsorption of CO₂ on the solid amine adsorbent. The pseudo-second order model could accurately describe the CO₂ adsorption process on the MIP-PEIs from the beginning to the end. Moreover, this adsorbent also exhibited good regeneration performance, retaining almost the same adsorption amount of CO₂ as the fresh material after ten adsorption–desorption cycles.