Large-Pore Mesostructured Silica Impregnated with Blended Amines for CO2 Capture

Mesoporous silica materials with different pore volumes were functionalized by wet impregnation with a variety of amines for the purpose of CO2 adsorption. The effects of the concentration and composition of amine blends, silica supports, and adsorption temperature on CO2 adsorption were investigated. The mechanism of an observed synergistic effect between blended amines is also discussed. The experimental results showed that in addition to the pore volume of the supports and the adsorption temperature the molecular functional groups of the blended amines play an important role and greatly affect the CO2 adsorption capacity. The silica material with the largest pores (MSU-F) had the highest CO2 adsorption capacity after impregnation with a mixture of 40 wt % tetraethylenepentamine and 30 wt % diethanolamine. For 100 kPa CO2, the adsorption capacity at 50 degrees C was 5.91 mmol/g.