Abstract
Charcoals were prepared from Japanese cypress (C. obtusa) and Japanese oak (Q. mongolica) by threecarbonization methods, (a) in a nitrogen stream, (b) in an air stream, (c) in a container with cover. The relationshipbetween the carbonization methods and the adsorption properties of the charcoals was investigated and the followingresults were obtained.
Regardless of the carbonization method or the kind of wood used, the surface of charcoals prepared at lowtemperature was acidic and that of charcoals prepared at high temperature basic. The surface of charcoals preparedby method (c) showed the highest acidity.
When benzene, iodine and phenol were adsorbed for short periods onto charcoals prepared by methods (a) and (c), the charcoal prepared at 600°C had the largest mean pore size, and also showed the fastest adsorption rate and thehighest adsorption capacity. Of the charcoals prepared by method (b), the charcoal prepared at 900°C had the highestadsorption capacity. The charcoal prepared at 1000°C showed a decrease in adsorption capacity because of thermalshrinkage of the pores.
For all methods, adsorption capacity for water vapor was lowest in the charcoal prepared at 600°C. However, the amount of water vapor desorbed when humidity decreased was highest in the charcoal prepared at 600°C It was found that the 600°C charcoal is the best for use in humidity-control.
