https://doi.org/10.1016/j.apsusc.2014.06.164
“Because impregnated moieties are usually weakly attached to the adsorbent, it is important to examine the effect of the regeneration temperature of the amino-loaded sample on the CO2 uptake. This aspect was addressed by measuring two isotherms for the same amine-loaded sample after being regenerated at two different temperatures. In Fig. 7, the CO2 adsorption isotherms obtained for the amino-loaded zeolite ZX0.2 at 348 K are shown after the sample was regenerated at 423 and 473 K. For the sake of comparison, the isotherm of the pristine zeolite ZX at this temperature was also included.”
“Fig. 7. Adsorption isotherms of CO2 at 348 K for ZX0.2 with regeneration of 423 and 473 K and ZX with regeneration of 573 K.”
“It may be observed that the CO2 uptake increases when a higher temperature of regeneration is applied and approaches that of the pure zeolite ZX. These results suggest that part of the loaded amine was removed upon heating at 473 K, a higher temperatures than MEA boiling point (443 K) even though TGA analysis indicates that most of the amine volatilizes only beyond 500 K (Fig. 3, inset). Nevertheless, in real PSA separation units, cycles are performed under nearly isothermal conditions (at least not higher than 373 K) and regeneration is performed under pressure swings. Adsorption uptakes should ideally be constant after pressure swings.”