Silica Gels with Ion-Exchange Surfaces

The ion-exchange arid catalytic properties of the aluminosilicate sites in H form are further considered in Chapter 6. So-called synthetic zeolites —gels made by reacting sodium silicate and aluminate—left in the sodium form were used for water but are unstable at low pH and are not generally useful for cation exchange. 

More stable silica-based exchangers fall into two classes inorganic surface modifications and organosilicon modifications where the surface is covered with organic ion-exchange groups held on the surface through carbon-silicon bonds. 

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