抄録
The heat of immersion method devised by Harkins-Jura in 1944 has such a significant disadvantage that the method is accompanied by an unavoidable error with the powders that have capillary condensation in adsorption of vapor of the liquid in which the powders are immersed. Previously, the authors have been presented an approvable means to develope the applicability of the heat of immersion method to many kinds of powders not as a standard method but as a common use independently of the capillary condensation phenomenon.
On the basis of the foregoing results, the surface areas of several kinds of oxide powders together with clay minerals were determined and the obtained results were compared with those from the other methods, briefly the B. E. T. method. Simultaneously, the effect of pretreatment of the powder samples on their surface area values was investigated.
The obtained conclusions are digested as follows :
(1) The heats of immersion in water for the powder samples which are equilibrated at an unsaturated water vapor pressure near before capillary effect provide surface area values that are in considerable agreement with those from the B. E. T. method using nitrogen as adsorbate.
(2) Though of course precise data could not be expected, the heat of immersion method may be capable of being extended to many kinds of powders as routine work regardless of the capillary condensation.
(3) The surface area values of silica gel, anatase and kaolinite are affected considerably by the condition of pretreatment (degasing temperature).
