Preparation and characterization of multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture

In this work, multi-walled carbon nanotubes impregnated with polyethyleneimine (MWCNT/PEI) have been prepared by wet-impregnation method with various PEI loadings for CO₂ capture. The surface features and morphology were observed by scanning electron microscopy (SEM) and the textural properties were analyzed by N₂/77 K adsorption-desorption isotherms. The CO₂ adsorption capacity was evaluated by thermogravimetric analysis (TGA) method at 15% CO₂ partial pressure. The MWCNT/PEI exhibited higher CO₂ adsorption capacity than pristine MWCNTs. This result suggested that amine groups were attached on carbon surfaces in the impregnation process, leaving CO₂ affinity sites on MWCNT surfaces. MWCNT/PEI exhibited superior cycle stability for CO₂ capture, indicating great potential for application in post-combustion technology.