Adsorption of carbon dioxide on modified mesoporous materials in the presence of water vapor

Aminosilane modified mesoporous silica as novel adsorbent for CO2 capture and separation from flue gases was prepared by grafting various aminosilanes; i.e., (3-aminopropyl)triethoxysilane (APS), N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPS) and (3-trimethoxysilylpropyl)diethylenetriamine (TA), on mesoporous silica, SBA-15. Pore walls of SBA-15 were modified uniformly with these aminosilanes and relatively high surface area and uniform pore size were retained. Adsorption capacities of CO2 in the presence of water were compared with that in the absence of water by a flow method. It was found that adsorption capacities of aminosilane modified SBA-15 under wet condition were comparable to that under dry condition. In particular, the adsorption capacity of TA-anchored SBA-15 reached 1.28 mol(.)kg(-1) in the presence of water vapor at 333 K. In addition, these adsorbents were completely regenerated by heating up to 423 K in He flow.