Comparative adsorption study on carbons from polymer precursors

The effect of the precursor polymer on nitrogen adsorption properties, pore size distribution and the hydrophilic/hydrophobic character of both the pyrolyzed char and the activated carbon was studied in the case of three basically different polymers, i.e. polyacrylonitrile, polyethyleneterephthalate and cellulose. Pyrolyzed samples were produced from these polymers and activated by steam at 900 degrees C. After a 50% burn-off, the pore volume and the specific surface area increase significantly and the pore size distribution is determined by that of the pyrolyzed char, i.e. the starting polymer. The activated sample derived from polyacrylonitrile is microporous, while the other two carbons contain both micro- and mesopores. Activation creates pores which are equally available for methanol and benzene and the heterogeneous surfaces become more benzophilic in all three polymers. The N-content has limited effect on the surface properties studied. (C) 2000 Elsevier Science Ltd. All rights reserved.