One-Pot Synthesis and Pelletizing of Polyethylenimine-Containing Mesoporous Silica Powders for CO₂ Capture

Polyethylenimine-containing mesoporous silica powders (PEI-MSP) were prepared through one-pot synthesis from mixtures of tetraethyl orthosilicate and PEI in water/methanol. This proposed route required only 4% of reaction time and energy and used 50% of chemical reagents used in two-step synthesis of PEI-loaded SBA-15 (PEI/SBA) prepared through impregnation, thereby decreasing the cost of the resulting adsorbents. The PEI component in the one-pot route functioned not only to provide amine active sites for CO₂ capture but also as a basic catalyst and a pore-structure-directing agent. The pelletized PEI-MSP using our proposed binder solution possessed high mechanical strength, durability, and CO₂ adsorption capacity and recovery, satisfying industrial requirements and reducing the pressure drop in practical use. Dynamic adsorption–desorption cycles of PEI-MSP powders and pellets revealed high thermal stabilities. Therefore, this one-pot synthetic route is promising for preparing PEI-MSP as appropriate adsorbents for CO₂ capture when using a temperature swing adsorption technology.