Thermally Stable Amine-Grafted Adsorbent Prepared by Impregnating 3-Aminopropyltriethoxysilane on Mesoporous Silica for CO2 Capture

In this paper, an amino-functionalized adsorbent for CO2 capture was synthesized by impregnating 3-aminopropyltriethoxysilane (APTES) on mesoporous silica. Amino functional groups were chemically bonded to silica support. Because of chemical bonds, the thermal stability of this adsorbent (205 °C) was greater than that of an adsorbent prepared by impregnating polyethylenimine on the same mesoporous silica (160 °C). The cyclic CO2 loading capacity was improved by increasing adsorption temperature, reaching a maximum of 89.3 mg CO2/g at 100 °C and then reduced at temperatures above 100 °C. Optimum regeneration temperature was determined at 120 °C. The adsorbent was stable for multiple adsorption–regeneration cycles operating at adsorption temperature of 100 °C in pure CO2 and regeneration temperature of 120 °C in atmosphere, respectively. The amino-functionalized mesoporous silica is a thermally stable adsorbent with relatively high CO2 loading capacity and high optimum adsorption and regeneration temperatures. These characteristics make the adsorbent suitable for CO2 capture application.