Development of Crosslinked PEI Solid Adsorbents for CO₂ Capture

Impregnated amine adsorbents show high CO₂ adsorption capacity, however, leaching out and evaporation of amines, urea formation problem was existed. These problems are critical to the long term operation of CO₂ capture, and related to the physical and chemical stability of amines at regeneration temperature. In order to overcome limitations, crosslinking method between amine groups was introduced. Crosslinkers having two amine reactive groups, such as acid, aldehyde were used to prepare crosslinked polyethyleneimine (PEI)-impregnated adsorbents. The viscosities of the crosslinked PEIs were increased compared to the pristine PEI. The structure and the amine ratio of the crosslinked PEIs were investigated by ¹³C NMR analysis. Simulated TSA cyclic operation was conducted by thermogravimetric analyzer (TGA), and all of crosslinked PEI-impregnated adsorbents were exhibited lower CO₂ capacity compared to PEI-impregnated adsorbents, but less urea formation was observed.