Enhanced adsorption of carbon dioxide on surface-modified mesoporous silica-supported tetraethylenepentamine: Role of surface chemical structure

Abstract

Amine-impregnated mesoporous silica materials were prepared using surface-modified silica supports for CO2 capture, and the effects of the surface chemical structure of the support on the CO2 adsorption performance of surface-modified silica-supported amines were investigated systematically. The thermal stability and CO2 adsorption characteristics of amine-impregnated materials were determined experimentally. The surface modification of mesoporous silicas by particular functional groups leads to increases in thermal stability of loaded amine and CO2 adsorption capacity. In particular, the CO2 adsorption performance in the presence of water vapor was remarkably enhanced by surface modification of the silica support. Computational analyses indicated that increases in the thermal stability of loaded amine and CO2 adsorption capacity were due to the hydrophilicity and electron donativity (nucleophilicity) of introduced functional groups. Compared to non-modified support, CO2 adsorption capacities for surface-modified silica supported amines were increased up to 118% in the absence of water vapor and 182% in the presence of water vapor. It is suggested that the surface structure of supports for amine-impregnated mesoporous silica materials plays an important role in CO2 adsorption performance.