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.