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Experimental study of pure and mixtures of CO2 and CH4 adsorption on modified carbon nanotubes
Molyanyan, E.; Aghamiri, S.; Talaie, M. R. & Iraji, N.
Abstract
In this work 3-[2-(2-aminoethylamino)ethylamino]propyl trimethoxysilane (TRI) was employed to
functionalize MWCNT containing hydroxyl groups (OH-MWCNT), and the XRD, FTIR, TGA and CHNS elemental
analysis techniques were used to characterize the resulted
adsorbents. The characterization results for amineMWCNT showed amine groups effectively attached to the
surface of the MWCNT. The equilibrium adsorption
capacity of pure CO2 and CH4 and their binary mixture on
the pristine MWCNT, OH-MWCNT and amine-MWCNT
was measured through a set of equilibrium adsorption
experiments at 303.2 and 318.2 K. Capacities of all three
types of adsorbents for CO2 adsorption were higher than
those for methane adsorption. Also, amine-MWCNT
demonstrated better performance on CO2 adsorption than
the other two adsorbents, especially at low partial pressures. The capacity of amine-MWCNT for pure CO2
adsorption was 2.5 and 4 times as much as those for pristine MWCNT and OH-MWCNT, respectively, at the
temperature of 303.2 K and the pressure of 0.2 bar. The
binary adsorption experiment revealed that CO2/CH4
selectivity for pristine MWCNT and amine-MWCNT in all
molar fractions of CO2 is about 1.77 and 7, respectively.
Keywords
Adsorption; Carbon dioxide; Carbon nanotube; Functionalization; Methane; Natural gas
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