EFFECTS OF ACTIVATION METHOD ON THE PORE STRUCTURE OF ACTIVATED CARBONS FROM APRICOT STONES

Two series of activated carbons were prepared from apricot stones by u sing carbonization followed by steam activation and one-step pyrolysis /activation in steam. The pore structure of the activated carbons was characterized by CO2 adsorption at 273 K and by N-2 adsorption at 77 K . The macro- and mesoporosity were determined by mercury porosimetry. Optical microscopy, scanning electron microscopy (SEM) and environment al scanning electron microscopy (ESEM) were used to examine the micros tructure of activated carbons. A considerable difference observed betw een the measured CO2 and N-2 surface areas indicates a narrow micropor osity in all the carbons. The two-step method produced better develope d meso- and especially macroporosity. The SEM and optical micrographs show that one-step pyrolysis/steam activation preserves the original c ell structure of the raw apricot stones. In general, the apparent surf ace areas of the two-step carbons are slightly higher than those of th e one-step carbons. However, the one-step method would provide lower p roduction costs because it would eliminate the separate carbonization stage. Copyright (C) 1996 Elsevier Science Ltd