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Polyethyleneimine-Modified Amorphous Silica for the Selective Adsorption of CO2/N2 at High Temperatures
journal contribution
posted on 2021-12-14, 13:34 authored by Cheng Li, Xiaoqing Wang, Anjie Yang, Peng Chen, Tianxiang Zhao, Fei LiuMechanochemistry
is very attractive as
an efficient, solvent-free, and simplified technique for the preparation
of composite adsorbents. Here, a series of polyethyleneimine (PEI)-modified
SiO2 adsorbents were prepared via mechanical ball milling
for selective adsorption of CO2 at high temperatures. The
structural properties of these adsorbents were characterized by XRD,
SEM, TGA, FTIR, and N2 adsorption–desorption. This
method can better disperse the PEI evenly in the SiO2 as
well as maintain the porous structure of the adsorbents by comparing
with the impregnated adsorbents. These adsorbents presented appreciable
performance in separating CO2 at high temperatures, and
the CO2 adsorption capacity of PEI(70%)/SiO2 is up to 2.47 mmol/g at 70 °C and 1.5 bar, which is significantly
higher than that of the same type of CO2 adsorbent reported
in the literature. Furthermore, the adsorbent of PEI(70%)/SiO2 provided an ideally infinite selectivity for CO2/N2 (15:85) at 70 °C. These results showed that mechanical
grinding methods are a simple and effective approach to producing
amine-modified silica composite adsorbents.
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Keywords
modified amorphous silicamechanical grinding methodsideally infinite selectivity70 ° cadsorption – desorptionhigh temperatures mechanochemistry70 %)/ sio2 subhigh temperaturesselective adsorptionadsorption capacitystructural propertiessimplified techniquesignificantly higherresults showedproducing amineporous structureeffective approachbetter disperse5 bar47 mmol