Spectroscopic Characterization of Humid CO2 Adsorption on Solid Supported Tertiary Amines

Aminosilica materials are promising candidates for CO₂ capture from dilute streams such as ambient air and flue gas. While ammonium bicarbonate formation is known to occur in aqueous amines in the presence of CO₂ there has been little evidence of its formation on solid supported analogues. To probe if the ammonium bicarbonate species can exist on solid supported amines, tertiary amines were grafted on to SBA15 and the materials were further characterized using in-situ FTIR spectroscopy in the presence of humid CO₂. Dry and humid CO₂ capacities for these adsorbents were also evaluated using fixed bed experiments and thermogravimetric analysis. This work shows that ammonium bicarbonates can exist on solid supported amines.