A method of characterization of carbonaceous materials using nongraphitized carbon black as a reference is considered. The Tarazona density functional theory was applied to amorphous solids to describe nitrogen adsorption on nongraphitized carbon black. This allows us to describe energetic heterogeneity without the need to invoke any energy distribution functions. To derive the pore size distribution (PSD) of porous carbon whose pore walls are non-graphitized, we used the entropy concept in the regularization method. With this approach PSD is more well-behaved than that obtained with the usual means. We applied this new theory to study the effects of technological parameters on porous structure of a series of activated carbon. (C) 2007 Published by Elsevier B.V.