Energy & Fuels, Vol.21, No.5, 2929-2934, 2007
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-methylbeptane is better adsorbed than n-heptane on the carbon sample by an inverse gas chromatography (IGC) adsorption study at 275-350 degrees C. Structural features of the carbonaceous material, entropy restrictions by steric parameters, diffusion conditions, and cooperative CH/pi interactions between CH in n-heptane and 2-methylheptane and pi electrons in the carbon walls determine the selective adsorption.