Improving the ion-exchange capacity and elution of Cu+2 from natural sedimentary zeolites.

The ion-exchange capabilities of natural zeolites from the western United States, representing the species chabazibe, clinoptilolite, erionite and mordenite, have been studied because of their potential use in environmental remediation and in hydrometallurgical processes. These, aw zeolite samples were found to contain Na+, K+, Ca+2 and Mg+2 as exchangeable cations, and all of these, with the exception of Na+, were found to seriously interfere with the exchange of Cu+2 from solution. Placing these zeolites in the Na+ form was found to increase their cation-exchange capacity, often massively. In addition, the elution of Cu+2 from the Na+ pre-exchanged zeolite is greatly facilitated when the deleterious K+, Ca+2 and Mg+2 hav been largely expelled. The relative influence of these deleterious ions on the uptake and elution of Cu+2 was determined.