Silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture under the flue gas condition

•Silica coated-MWCNT impregnated with PEI was synthesized.•Amine groups of PEI gave CO2 affinity sites on MWCNT surfaces.•The S-MWCNT/PEI(50) exhibited the highest CO2 adsorption capacity.

In this study, silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine (PEI) were prepared via a two-step process: (i) hydrolysis of tetraethylorthosilicate onto multi-walled carbon nanotubes, and (ii) impregnation of PEI. The adsorption properties of CO2 were investigated using CO2 adsorption–desorption isotherms at 298 K and thermogravimetric analysis under the flue gas condition (15% CO2/85% N2). The results obtained in this study indicate that CO2 adsorption increases after impregnation of PEI. The increase in CO2 capture was attributed to the affinity between CO2 and the amine groups. CO2 adsorption–desorption experiments, which were repeated five times, also showed that the prepared adsorbents have excellent regeneration properties.

Graphical abstractFabrication and CO2 adsorption process of the S-MWCNTs impregnated with PEI.Figure optionsDownload full-size imageDownload as PowerPoint slide