ION-EXCHANGE PROPERTIES OF GEOLITE K-G RELATIVE TO STRONTIUM AND CESIUM

Ion-exchange properties of the low-silicon geolite K-G relative to strontium and cesium and to sodium and calcium under equilibrium conditions are studied. The distribution coefficients for Sr2+, Ca2+, Cs+, and Na+ ions are determined. The sorption capacity of the zeolite in equivalents of strontium, calcium, and sodium is 5.0 mmole/g and of cesium is 4.0 mmole/g. It is shown that the selectivity of the zeolite changes with the sorption capacity. Up to 50% exchange the zeolite K-G is selective to Sr2+, Ca2+, and Cs+ ions, the selectivity diminishing in the order Sr2+ > Ca2+ > Cs+ > K+ > Na+. Upon 50% exchange the zeolite becomes selective to K+ ion. In concentrated sodium salt solution (5 M) the zeolite is much more selective to strontium (K(d) congruent-to 10(4) ml/g) than to calcium (K(d) congruent-to 6 ml/g). The ion-exchange characteristics obtained for the zeolite K-G allow it to be considered a promising sorbent for isolation of Sr-90 from solutions containing substantial amounts of sodium salts (up to 5 M) and small amounts of calcium and cesium.