Adsorption of n-Heptane and 2-Methylheptane in the Gas Phase on Polyvinylidene Chloride-Based Microporous Activated Carbon

The selective adsorption of n -heptane and 2-methylheptane was tested on polyvinylidene chloride-based microporous carbon (CMS-IMP12) prepared from pyrolysis of poly(vinylidene chloride-co-vinyl chloride) (PVDC-PVC) copolymer. CMS-IMP12 was characterized by textural analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) and Raman spectroscopies. These results indicate the presence of graphene subunits inside the amorphous carbon and great quantity of sp 2 carbon type in CMS-IMP12. It was found that 2-methylheptane is better adsorbed than n -heptane on the carbon sample by an inverse gas chromatography (IGC) adsorption study at 275−350 °C. Structural features of the carbonaceous material, entropy restrictions by steric parameters, diffusion conditions, and cooperative CH/π interactions between CH in n -heptane and 2-methylheptane and π electrons in the carbon walls determine the selective adsorption.