CO<sub>2</sub> Capture by As-Synthesized Amine-Functionalized
MCM-41 Prepared through Direct Synthesis under Basic Condition
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Abstract
The as-synthesized
amine-functionalized MCM-41 material was prepared
through direct synthesis by co-condensation of tetraethyl orthosilicate
(TEOS) with 3-aminopropyl triethoxysilane (APS) at different molar
ratios and a pH of approximately 13 for CO<sub>2</sub> capture under
various CO<sub>2</sub> concentrations, temperatures, and moistures.
The prepared as-synthesized APS-functionalized MCM-41 (as-APS/MCM)
possessed nitrogen content up to 3.46 mmol N/g and CO<sub>2</sub> adsorption
capacities up to 1.18 mmol/g under 15% CO<sub>2</sub> in N<sub>2</sub> at 35 °C and 1.74 mmol/g under pure CO<sub>2</sub> at 25 °C.
The CO<sub>2</sub> adsorption capacity was 73% higher than the APS-grafted
calcined MCM-41 prepared by postmodification. Because the CO<sub>2</sub> adsorption capacity of the as-APS/MCM was found to come mainly from
the coated APS rather than the incorporated APS, prehydrolysis of
TEOS and post-treatment including template removal and APS neutralization
were not required. Dynamic adsorption–desorption cycles revealed
that the as-APS/MCM possessed high thermal stability for CO<sub>2</sub> capture