The investigation on cationic exchange capacity of zeolites: the use as selective ion trappers in electrokinetic soil technique

The Cation Exchange Capacity, CEC, of porous zeolites allows to adsorb in the framework cavities the cations as pollutant heavy metal ions. We investigate the CEC behaviour of different zeolites in different experimental conditions; in solution where the ion’s mobility is spontaneous and free and in the electrokinetic system where the ion’s mobility is induced by the electric field. The aim of this study is to investigate if the CEC of zeolites are useful to create a special interface region of zeolites, that when placed in the electrokinetic cell, just before the cathode, could allow to locate and concentrate the heavy metallic ions, during their migrating process. The zeolite 13 X investigated in the electrokinetic proofs, retains a good high ions adsorption in the electrokinetic conditions, even if quite smaller than if free solution, and acts as confined trap for the heavy metal ions. In fact no trace of metallic deposition are present on the electrode’s surface.