Study of CO2 Sorption Kinetics on Electrospun Polyacrylonitrile-Based Carbon Nanofibers

Electrospun carbon nanofibers (CNFs) exhibit a decent CO2 sorption capacity and outstanding CO2/N-2 selectivity. In this work, the sorption rate as another practically relevant parameter for CO2 adsorption is analyzed for different carbonization temperatures. Equilibration curves obtained from different CO2 sorption isotherms are discussed qualitatively and quantitatively, employing empirical models for pseudo-first- and second-order reactions. The sorption rate constants are found to be highly dependent on the carbonization temperature of the CNFs and the applied pressure during the measurement. Furthermore, two distinct processes of sorption are observed, which are attributed to different sorption sites on the surface and the inner volume of the CNFs.