CO₂ sorption performance by aminosilane functionalized spheres prepared via co-condensation and post-synthesis methods

Amine functionalized silica microspheres were synthesised via a modified Stöber reaction for carbon dioxide (CO₂) adsorption. A number of adsorbents were synthesized by co-condensation and post synthesis immobilization of amines on porous silica spheres. CO₂ adsorption studies were carried out on a fixed bed gas adsorption rig with online mass spectrometry. Amine co-condensed silica spheres were found to adsorb up to 66 mg CO₂ g⁻¹ solid in a 0.15 atm CO₂ stream at 35°C. Simple post-synthesis addition of aminopropyltriethoxysilane to amine co-condensed silica was found to significantly increase the uptake of CO₂ to 211 mg CO₂ g⁻¹ under similar conditions, with CO₂ desorption commencing at temperatures as low as 60°C. The optimum temperature for adsorption was found to be 35°C. This work presents a CO₂ adsorbent prepared via a simple synthesis method, with a high CO₂ adsorption capacity and favorable CO₂ adsorption/desorption performance under simulated flue gas conditions.