Solid Amine Adsorbent Prepared by Molecular Imprinting and Its Carbon Dioxide Adsorption Properties

A carbon dioxide imprinted solid amine adsorbent (IPEIA‐R) with polyethylenimine (PEI) as a skeleton was conveniently prepared by using glutaraldehyde to cross‐link carbon dioxide‐preadsorbed PEI. As confirmed by FTIR, FT‐Raman, and 13C NMR spectroscopy, CO2 preadsorbed on PEI could occupy the reactive sites of amino groups and act as a template for imprinting in the cross‐linking process. The imino groups formed from the cross‐linking reaction between glutaraldehyde and PEI could be reduced by NaBH4 to form CO2‐adsorbable amino groups. The adsorption results indicated that CO2 imprinting and reduction of imino groups by NaBH4 endowed the adsorbent with a higher CO2 adsorption capacity. Compared with PEI‐supported mesoporous adsorbents, the solid amine adsorbent with PEI as a skeleton can avoid serious pore blockage and CO2 diffusion resistance, even with a high amine content. The solid amine adsorbent with PEI as a skeleton showed a remarkable CO2 adsorption capacity (8.56 mmol g−1) in the presence of water at 25 °C, owing to the high amine content and good swelling properties. It also showed promising regeneration performance and could maintain almost the same CO2 adsorption capacity after 15 adsorption–desorption cycles.