Improved CO2 adsorption capacity and fluidization behavior of silica-coated amine-functionalized multi-walled carbon nanotubes
The adsorption capacity and fluidization behavior of silica-coated amine-functionalized multi-walled carbon nanotubes (MWCNTs) were studied in this work. The coupling of both studies is fundamental for the practical application of CO2 sorbents in fluidized beds. Sorbents were prepared by hydrolysis of tetraethylorthosilicate (TEOS) onto acid-treated multi-walled carbon nanotubes followed by impregnation with monoethanolamine (MEA). The effects of different loading amounts of MEA and TEOS on CO2 uptake were investigated using thermogravimetric analysis under a simulated flue gas composed of 15%CO2/85% N2. At the optimal loadings of TEOS (30 ml) and MEA (30 wt%) on MWCNTs, 2.67 wt% of CO2 was captured at 25 °C, while the adsorption capacity of the pristine MWCNTs before any modification was negligible. Adsorption/desorption tests repeated 25 times also showed that the prepared sorbent has excellent stability during the cyclic operation; 9.42% reduction of the uptake was reported. Fluidizability of the most promising sorbent was also assessed when adding hydrophobic silica nanoparticles (NPs). Maximum bed expansion of 3.9 was achieved in the presence of 7.5 wt% silica NPs which was comparable by the amount of 2.24 belonged to raw MWCNTs. Enhancement of fluidity may be attributed to the decreased van der Waals attraction forces between the particles of sorbent. Besides, the CO2 adsorption capacity of the sorbent mixed with 5 wt% silica NPs was surprisingly increased by approximately 8%, reaching ~3 wt% of CO2.
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Elsevier
2021-06-03
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| Subjects: | Amine functional groups, Multi-walled carbon nanotubes (MWCNTs), CO2 adsorption, Surface modification, Fluidization behavior, |
| Online Access: | http://hdl.handle.net/10261/264337 https://api.elsevier.com/content/abstract/scopus_id/85116316280 |
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