Sorption equilibrium and thermal regeneration of acetone and toluene vapors on an activated carbon

Adsorption and thermal regeneration dynamics of acetone on activated carbon were compared to those of toluene. The adsorption isotherms of acetone on the activated carbon were type-II, but they approached type-Ill with an increase in temperature. On the other hand, those of toluene were type-I in the experimental range. Although the temperature excursion of toluene was higher than that of acetone in the activated carbon bed, the breakthrough shape of toluene was steeper due to the strong adsorption affinity. Compared to toluene, more concentrated acetone within shorter period of time could be obtained from the activated carbon bed by hot nitrogen purge regeneration because its isotherm approached type-in at high temperature. Therefore, the energy requirement and purge gas consumption for acetone desorption were significantly changed with purge gas velocity, regeneration temperature, and initial bed loading, which was different from toluene. A nonequilibrium and nonadiabatic/nonisothermal model was used to fit temperature and concentration profiles of adsorption and thermal regeneration. Even though the adsorption of acetone was performed in a low concentration range, the multilayer adsorption isotherm model should be applied for the regeneration step to design the activated carbon bed system more accurately.