Abstract
The surface properties of the organophilic silica gels were investigated by the adsorption of argon at 77°K, of water vapour at 288°K and of n-heptane at 273°K and the heat of immegions of water and n-heptane, respectively, on the samples which the native silica gels were treated by methanol, ethanol, butanol, pentanol, hexanol, octanol, decanol, dodecanol and tetradecanol. The following results were confirmed:
(1) Since the BET surface area of argon and of water on the native silica gel showed good agreement, and the one of argon on the activated carbon agreed with the one of n-heptane, the argon molecule could be adsorbed on both the organophilic and the hydrophilic surface.
(2) The argon surface areas on the surface-treated samples showed remarkable decrease, increasing the carbon chain of alcohol. The water surface area showed remarkable decrease in comparison with the argon surface area on each sample.
(3) The surface area from argon adsorption on the surface-treated silica gels showed the sum of the surface areas from water and from n-heptane, respectively.
(4) The heat of immersion in water and n-heptane on the surface-treated silica gels were well-explained by using the respective surface areas from water and n-heptane.
