High-performance amine-montmorillonite composite aerogels via polyethyleneimine-induced gelation for sustainable carbon dioxide capture.

HYPOTHESIS: Traditional solid amine adsorbents face challenges like pore blockage, amine agglomeration, and high preparation costs. We hypothesize that utilizing polyethyleneimine (PEI) as both a crosslinker and an amine source with low-cost montmorillonite (MMT) nanosheets can overcome these limitations by creating a self-crosslinked 3D porous network.

EXPERIMENTS: Monolithic MMT/PEI composite aerogel adsorbents were synthesized via a facile, one-step PEI-induced sol-gel strategy. We systematically investigated the impact of the organic amine loading method, PEI concentration, and porosity on the material's CO2 adsorption performance.

FINDINGS: The optimal MP70A adsorbent (70 wt% PEI) achieved a high CO2 uptake of 1.61 mmol/g at 75 °C under 60% CO2/40% N2 atmosphere and exhibited excellent cyclic stability, with only a 7.38% capacity decay after 10 cycles. This superior performance stems from the synergy between the 3D MMT framework's spatial confinement and reversible amino-CO2 chemisorption. PEI successfully bridged the MMT nanosheets via electrostatic interactions and hydrogen bonding to assemble a template-free 3D network. This monolithic structure suppresses amine aggregation and pore blockage at high loadings, ensuring active site accessibility, rapid mass transfer. Ultimately, this one-step strategy provides a scalable, cost-effective solution for sustainable industrial CO2 capture.