The CO2 adsorption on modified ordered mesoporous carbon
Date Issued
2015
Date
2015
Author(s)
Lin, Yichen
Abstract
In this study, the ordered mesoporous carbon (OMC) with high surface areas and high pore volume was prepared by hydrothermal method, and then modified by nitric acid solution, which was named OMCA. OMCA materials were modified by grafting different amine separately, which were tetraethylenepentamine (TEPA) , tris（2-aminoethyl）amine (TAEA) and polyethylenimine (PEI), and loaded with varied amounts (5, 10 and 20 wt%). The textual, structural properties, and surface morphology of all prepared materials were characterized by powder X-ray diffraction (XRD), N2 sorption isotherms, transmission electron microscopy(TEM) and Fourier transform infrared (FTIR) spectroscopy. Carbon dioxide capture capacity of amine-modified mesoporous carbon was obtained by thermogravimetric analysis (TGA) and volumetric adsorption analyzer (BET); the latter was also used to investigate the adsorption performance on CO2/N ratio. The reaction mechanisms of CO2 adsorption on amine-grafted OMCA were confirmed by infrared spectroscopy. The experimental results indicated that the optimal amine loaded amount is 10 wt% for OMCA-TEPA and OMCA-TAEA material. OMCA-TEPA-10 has highest adsorption amount. The results of the volumetric method showed that OMCA- TEPA-10 also had the highest chemical adsorption amounts, 13.23 μg/m2,which was more than OMCA-TAEA-10, 12.96 μg/m2 and OMCA-PEI-10, 7.03 μg/m2. The CO2/N molar ratio were 0.027、0.037 and 0.031, respectively. OMCA-TEPA-10 had highest chemical adsorption amounts but lowest CO2/N ratio due to the steric hindrance. By in-situ FTIR spectroscopy, we showed that the amine groups reacted with CO2 and formed carbamic acids and carbamate under dry conditions. The intensities of ammonium carbamate, carbamic acids and carbamate changed with temperature, and the chemical adsorption intensities had the same trends.
Subjects
mesoporous carbon
CO2 adsorption
amine-modified
volumetric method
in-situ FTIR
Type
thesis
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