The characteristics of adsorption and desorption of benzene and toluene were investigated at a fixed bed packed with the activated carbon and activated carbon fiber. Through breakthrough experiments under various feed concentration conditions, it was found that the slope of mass transfer zone and the tailing in the breakthrough curves were different from the feed conditions due to different heats of adsorption. In hot nitrogen desorption, the regeneration time and mass transfer zone of the toluene desorption curve were longer than those of the benzene desorption curve because of the difference in adsorption affinity. With an increase in the regeneration temperature, the height of roll-up and the sharpness of desorption curves increased but the regeneration times decreased. The adsorption capacities of the activated carbon and activated carbon fiber after three-time thermal regenerations decreased about 25% and 37% for benzene and 18% and 25% for toluene, respectively. To investigate the effect of the regeneration temperature on the energetic efficiency, the characteristic desorption temperatures of toluene and benzene were investigated by calculating purge gas consumption and temperature.

This study discusses regeneration of mercury-contaminated, activated carbon from adsorption in the mercuryrecovery process. Mercury in activated carbon was desorbed by thermal treatment, and the regeneration efficiency was confirmed by mercury content and iodine adsorption comparing new and spent activated carbon. Up to 95% of mercury desorbed and up to 86% adsorption performance regenerated at 673 K. Therefore, it is expected that activated carbon can be reused many times by regenerating it through thermal treatment without disposing of mercury-containing activated carbon.