N-enriched GO Adsorbent Series for Selective Adsorption of CO2:
Characterization, Equilibrium, and Thermodynamic Studies
Abstract
In this study a series of GO-based adsorbents were assembled via
impregnation method using N-resources: 3-aminopropyl-triethoxysilane
(APTS) as primary amio-silane, Piperazine (PIP) as secondary cyclic
diamine, and ethanolamine (EA) as primary amine. The influence of amine
type, adsorption temperature and pressure were undertaken to obtain the
best CO2 adsorption performance. The characterizing techniques including
FTIR, SEM, TGA, BET, BJH, and MP confirmed well impregnation of amine
functionalities to the GO framework and high thermal stability of
adsorbents. GO/APTS showed the maximum CO2 uptake (43.114 mmol/g)
predicted by the Sips isotherm model and the highest CO2 ¬(15% V,
balanced N2) selectivity (33.7 %) estimated by the ideal adsorbed
solution theory. The experimental adsorption capacity of GO/APTS is 2.3
times higher than pristine GO. This behavior highlights the role of
electron-donor amine and methyl groups and high molecular weight of APTS
as well as high interfacial area of GO/APTS in CO2 capture.