Effectiveness of clinoptilolite in removing toxic cations from water: a comparative study

In order to evaluate the influence that structural and/or chemical inconsistencies exert over clinoptilolite behavior as an ion exchanger, a study has been performed aiming to compare the cation exchange properties of three different clinoptilolite-rich tuffs. Equilibrium data have been collected on two samples, coming from a Greek site and a Turkish site and having a similar framework chemistry. Exchange isotherms have been determined for some cation pairs of interest for practical applications and the related thermodynamic quantities calculated. The results, which have been compared with previously published data on a clinoptilolite sample from Sardinia (Italy), have shown analogous but not identical behaviors, possibly due to modest but not negligible differences in zeolite structure and/or original chemistry.