Polyethylene Polyamine-Modified Chitosan Aerogels: Enhanced CO₂ Adsorbents with Lamellar Porous Structures

Due to the continuous growth of global carbon dioxide emissions, the development of cost-effective carbon dioxide capture technology has attracted extensive attention. Amino-modified chitosan aerogels with lamellar porous structures are good candidates as carbon dioxide adsorbents because of their degradable properties and low energy consumption. Polyethylene polyamine-modified chitosan aerogels (PEPA-CSs) were prepared through a process of crosslinking and freeze-drying using a chitosan solution, polyethylene polyamine (PEPA), and epichlorohydrin (ECH) as raw materials. The amino group of PEPA was proven to be successfully grafted on the chitosan surface by FITR and XPS. The SEM and TEM analysis showed a rich three-dimensional porous structure and a good rigidity and bearing capacity of the PEPA-CS. The adsorption capacity was significantly increased by PEPA grafting with a maximum value of 1.59 mmol/g at 25 °C and 1 bar through both physical and chemical interactions, which indicates a potential for broad application prospects in industrial CO₂-capture applications.