engleski

Removal of Heavy Metal Ions from Solutions by Means Zeolites. Part 3. Influence of Sodium Ions Concentration in the Liquid Phase on the Kinetics of Exchange Processes Between Cadmium Ions from Solution and Sodium Ions from Zeolite A

Kinetics of exchange processes between the sodium ions from zeolite A and cadmium ions from solutions containing different contents of Na+ ions were determined by measuring the changes in the concentrations of cadmium and sodium ions in both zeolite and the liquid phase during the exchange processes. The exchange kinetics were analyzed in accordance with the kinetic model derived on the basis of the second order forward reaction between the cadmium ions from solution and sodium ions from zeolite A, and the second order backward reaction between sodium ions from solution and cadmium ions from zeolite A. The equilibrium cadmium uptake decreases with increasing concentration of the sodium ions in the liquid phase in accordance with the mass action law derived from the proposed model of the exchange process. This finding, together with an excellent agreement between the measured exchange kinetics and the exchange kinetics calculated by numerical solutions of the model equations, show that the exchange process takes place in accordance with the proposed model.

Zeolite A; Ion exchange; Sodium ions; Cadmium ions; Exchange kinetics

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