Sorption of Ferric and Ferrous Ions on Silica

The sorption of ferric and ferrous ions from aqueous solutions on the silica powder, obtained from colloidal dispersion of silica (silica sol), was studied as a function of their concentrations and solution pH. The amount of sorbed ferric and ferrous ions increases with increasing final pH of the solution. The sorption isotherms are of high-affinity type. A sorption mechanism of ferric and ferrous ions from aqueous solutions on silica is proposed.