Spent granular activated carbon, used for treating kraft pulping waste water, was regenerated. in an atmosphere of steam. Regenerating temperature and time were 620N9000C and 35. minutes respectively. The yield of regenerated activated carbon decreased with increasing temperature of rotary kiln regenerator and the same was true of its bulk density. But its strength decreased slightly.
Adsorptive capacities of activated carbon, which was regenerated at high temperature, was superior to newly activated carbon.
Studies on pore-size distribution based upon mercury prosimetry showed that the regeneration at high tempera re enlarged the pore-size. Consequently, adsorptive capacities for large melecules, e. g., molasseg. and kraft lignin, markedly increased. lnternal surface area of regenerated activated carbons was estimated by means of mercury porosimetry. lnternal surface area was closely correlated with molasses number.
From the thermal analysis, it was found that regenerated activated carbon and newly activated one showed the same thermal property.