CO2 Adsorption of Aminopropyltrimethoxysilane-and-Tetraethylenepentamine-Co-Modified Mesoporous Silica Gel

3-Aminopropyltrimethoxysilane (APTS) and tetraethylenepentamine (TEPA)-co-functionalized mesoporous silica gel (MSG) composites were prepared for CO2 adsorption. The surface functional groups, thermal stability, and pore structures of the composites were tested using FT-IR, TGA, and N2 adsorption–desorption techniques, respectively. The effects of the amine loading, adsorption temperature, and influent flow rate on CO2 adsorption were experimentally investigated. The results indicate that the synergistic effects of APTS, TEPA, and Si-OH on MSG enhanced CO2 adsorption performance. In addition, the amine-co-modified MSG exhibited good cyclic regenerability and rapid adsorption kinetics.