Solubility and Dissolution Rate of Amorphous Silica in Distilled and Sea Water at 20°C

Abstract

The solubility of amorphous silica in sea water is about 85mg-SiO₂/l at 20°C, which is less than that in distilled water (about 113mg-SiO₂/l). The dissolution rate seems to be controlled by the amount of silica gel present and its solubility. Silica gel in sea water is transformed to dissolved silica at a much faster rate than in distilled water. A maximum value of dissolved silica is observed during the process of dissolution under no abrasion condition, when the dissolution rate is very large. The differences in the solubility and in the dissolution rate of amorphous silica in distilled and in sea water cannot be explained by the difference in pH values of the waters but seem to be due to the salts present in sea water.