LOW-TEMPERATURE THERMAL-DESORPTION OF AROMATIC-COMPOUNDS FROM ACTIVATED CARBON

Low-temperature thermal desorption of three aromatic compounds (toluen e, chlorobenzene, and nitrobenzene) loaded on activated carbon was inv estigated, Desorption kinetics of these compounds followed an exponent ial-decay-type model assuming a distribution of sites over a range of activation energies. The activation energies of toluene, chlorobenzene and nitrobenzene were 17.6, 26.0, and 35.6 kJ mol(-1), corresponding to initial surface concentrations of 190, 300, and 610mg g(-1), respec tively, The desorption parameters determined using a simplified model predicted the aqueous phase adsorption of toluene and nitrobenzene and were used to estimate the residual contaminant concentrations as a fu nction of time and temperature, The presence of electron-withdrawing f unctional groups increases the activation energy and thus the higher t emperature required for desorption. (C) 1997 Elsevier Science B.V.