ie404403q_si_001.pdf (1.19 MB)
Probing the Adsorption/Desorption of CO2 on Amine Sorbents by Transient Infrared Studies of Adsorbed CO2 and C6H6
journal contribution
posted on 2014-03-19, 00:00 authored by Walter
Christopher Wilfong, Steven S. C. ChuangCO2 diffusion limitations and readsorption of desorbed
CO2 during removal from immobilized amine sorbents could
significantly reduce the effectiveness of CO2 capture processes.
To decouple CO2 diffusion from desorption/readsorption
on silica and tetraethylenepentamine (TEPA)/silica sorbents, a new
transient diffuse reflectance infrared Fourier transform spectroscopy
(DRIFTS) method was carried out by using benzene as a surrogate probe
molecule. Comparison of the infrared intensity profiles of adsorbed
CO2 and Si–OH (which adsorbs benzene) revealed that
slow rates of CO2 uptake and desorption are a result of
(i) CO2 diffusion through an interconnected network produced
from CO2 adsorbed inside of the amine/silica sorbent pores
and (ii) readsorption of CO2 on the amine sites inside
of the pores and at the external surface of the sorbents. High rates
of CO2 adsorption/desorption onto/from the immobilized
amine sorbents could be achieved by sorbents with low amine density
at the external surfaces and pore mouths.