PFG NMR-STUDY OF SELF-DIFFUSION OF LOW-CARBON CHAIN-LENGTH PARAFFINS IN CARBONACEOUS ADSORBENTS

The molecular self-diffusion of different hydrocarbons in two activated carbons (ASA-H and CMS-H) was studied using pulsed-field gradient NMR. The estimated self-diffusion coefficients correspond with the half-width of the micropores of the used adsorbents and decrease with the increasing length of the hydrocarbon chain. In active carbon CMS-H the increase in activation energies with increasing molecular chain length is much more pronounced than in ASA-H. © 1992.