posted on 2012-05-16, 00:00authored byAliakbar Heydari-Gorji, Abdelhamid Sayari
This work examines the stability of polyethylenimine(PEI)-impregnated
mesoporous silica for CO2 removal over a wide range of
conditions. The support used was a SBA-15 silica with platelet morphology
and short pore channels (SBA-15PL). The effect of long-term exposure
to different gaseous streams, including carbon-free air (CFair), simulated
flue gas (SFG), and different CO2/O2/N2 mixtures on the carbon dioxide adsorption capacity was investigated.
Extensive CO2 adsorption–desorption cycling using
dry and humid streams at different adsorption and regeneration temperatures
was also carried out. Based on adsorption data, as well as diffuse
reflectance infrared Fourier transform (DRIFT) and 13C
CP MAS NMR measurements, it was found that PEI-modified adsorbents
exhibit (i) high thermal stability at moderate temperatures, (ii)
highly stable CO2 uptake in the presence of moisture, (iii)
extensive degradation in the presence of dry CO2, particularly
at high temperature, (iv) fast degradation upon exposure to CFair
even at moderate temperatures, (v) excellent stability in the presence
of humidified gases containing both CO2 and O2.