Mechanism of Silica Removal

The removal of silica from solution by magnesium compounds is a nonstoi-chiometric reaction and proceeds by a surface adsorption mechanism with the formation of magnesium silicate see reaction (10.15)  

The quantity of magnesium oxide required to remove silica is not proportional to the amount of silica removed. This action is characteristic of adsorption reactions, and the Freundlich equation closely fits the data see Equation (10.16)  

---