Activation of a bentonite by an ammonium salt: evolution of the exchange capacity and of the specific surface area.

Activation of a bentonite by an ammonium salt : evolution of the exchange capacity and of the specific surface area. The treatment of an Algerian bentonite with an ammonium chloride solution under refluxing conditions and with various heating durations led to an evolution of the cation exchange capacity and of the porosity of the treated clay. The cation exchange capacity increased by up to 20 % of the initial value after 48 hours of heating then decreased progressively. The specific surface area increased up to a maximum value of 156 m(2).g(-1), corresponding to a 60 % increase with respect to the, initial value and also decreased progressively indicating a slow destruction of the aluminosilicate network and the possible formation of amorphous silica-alumina.