EVALUATION OF NATURAL PHILLIPSITE AND CHABAZITE AS CATION-EXCHANGERS FOR COPPER AND ZINC

Chabazite and phillipsite, two zeolites widespread in many volcaniclas tic deposits in central-southern Italy, were evaluated as cation excha ngers for the removal of copper and zinc from aqueous solution. Equili brium and kinetics of copper and zinc exchange reactions for sodium we re investigated in order to verify the selectivity and the uptake rate of both zeolites for these heavy metals. Thermodynamic quantities, su ch as equilibrium constant, K-a, and Delta G degrees, as well as rate constant, K, were computed, and they showed that Na-chabazite displays a moderate selectivity and a favorable kinetics for copper, whereas i n ail the other cases uses in wastewater treatment are not recommended .