Abstract
The amounts of micropore and external surface areas were obtained from α3-plots of Ar adsorption isotherms at 77K on the silica gels treated with several kinds of alcohols (methanol, ethanol, butanol, octanol, dodecanol and cetanol). The relationship between the amount of micropore or external surface area and the size of surface group were derived mathematically, assuming that the cylindrical pore as the pore of silica gel used and the exponential distribution for the pore size distribution of silica gel, L(r)dr, defined as the length of pores which have radii in a range of r to r+dr. It was found that these equations agreed with the experimental results; the diameter of the micropore is in the range σ to 4σ and the pore diameter in the external surface is larger than 8σ in which σ is the diameter of the Ar molecule.
