Thermal and Chemical Stability of Regenerable Solid Amine Sorbent for CO₂ Capture

Abstract

The adsorption and desorption of CO 2 and SO 2 on an amine-grafted SBA-15 sorbent has been studied by in situ infrared spectroscopy coupled with mass spectrometry. CO 2 adsorbed on an amine-grafted sorbent as carbonates and bicarbonates, while SO 2 adsorbed as sulfates and sulfites. The CO 2 adsorption capacity of the amine-grafted sorbent was almost twice as much as that of a commercial sorbent. The adsorption of CO 2 in the presence of H 2 O and D 2 O shows an isotopic shift in the IR frequency of adsorbed carbonate and bicarbonate bands, revealing that water plays a role in the CO 2 adsorption on amine-grafted sorbents. Although the rate of adsorption of SO 2 was slower than that of CO 2, the adsorbed S surface species is capable of blocking the active amine sites for CO 2 adsorption. A temperature-programmed degradation study of the amine-grafted sorbent showed that the surface amine species are stable up to 250 °C in air.