https://doi.org/10.3390/pr8121531
“Usually, CO2 adsorption involves a reaction between the acidic CO2 molecules and the modified basic active sites and for this reason amine–based adsorbents are extensively studied with regard to enhancing CO2 adsorption capacity and selectivity [7]. Amine impregnation is advantageous because it increases tolerance to water vapor in the gas feed of mesoporous silicas. On the other hand, several disadvantages are also present including high regeneration cost, equipment corrosion and oxidative degradation of some amines [21]. To investigate this last aspect, special attention has been devoted to the thermal stability of sorbents investigated here.
Figure 16 reports the TG thermograms of APTES20 (a) and APTES40 (b), respectively, after different cycles of regeneration. In the APTES20 sample, the initial amount of organic was ca. 16%, with a decrease to 14% after the first cycle of regeneration, a value that remains constant during all the other cycles of CO2 adsorption. On the other hand, the APTES40 sample (24.56% total weight loss before the adsorption tests) shows a weight loss of ca. 24% after the first cycle of adsorption; such a value decreases to 20% and then remains constant after the ninth cycle.”
