A simple method for the determination of the hydroxyl groups of silica was studied. A thermogravimetric analysis combiend with D2O vapor pretreatment was applied to determine both the surface and the inner hydroxyl contents of the silica particle. The number of hydroxyl groups was calculated by the difference in the TG weight loss between the untreated and treated samples.
The reactivity of the pre-heated silica surface is represented by the degree of rehydration reaction with H2O vapor, and it decreases with increase in the pre-heating temperature. The temperature dependency of the number of hydroxyl groups can be measured more accurately by considering the degree of rehydration.
