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, and13 C 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.