THERMOGRAVIMETRIC INVESTIGATION - SOLID-STATE ION-EXCHANGE PROCEDURE OF CU2+, CO2+, NI2+ AND FE2+ IONS INTO MONTMORILLONITE

Ion-exchange of transition metal ions into montmorillonite was investi gated using two different ion-exchange procedures. Performing ion-exch ange from aqueous solution of the respective metal ion leads to materi al possessing measurable Bronsted acidity, while the solid-state excha nge materials show predominantly Lewis acidity. Measurements by means of a derivatograph allowed us to construct a feasible reaction mechani sm for solid-state ion exchange. Satisfactory correlation was found be tween the results calculated from the reaction steps assumed and the m easurements by means of a derivatograph.