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

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.