On surface of micropores and fractal dimension of activated carbon determined on the basis of adsorption and SAXS investigations

Granulated commercial activated carbon obtained from hardcoal was separated for fractions, by elutriation, in an air stream of constant Bow-rate. Thre e samples of different fall down distances from the outlet tube were demine ralized. Benzene adsorption isotherms were determined at 293 K and SAXS mea surements were performed for each one. The Dubinin-Izotova and Dubinin-Stoe ckli equations were used for evaluation of micropore structural parameters of examined carbon samples. On the basis of these equations different metho ds of calculation of geometric surface area were discussed. Obtained result s were compared with values evaluated by using the method proposed hare. Th is method comprises results of SAXS and adsorption measurements. Changes of geometric surface area were confirmed by analysis of surface roughness mea sured by fractal dimension. The values of fractal dimension were obtained b y method of calculation on the basis of adsorption data proposed previously by Ehrburger-Dolle and were compared with modification proposed here. This modification is based on well known correlation given by McEnaney. Obtaine d values of fractal dimension were compared with values determined on the b asis of SAXS data. (C) 2000 Elsevier Science Ltd. All rights reserved.