UPTAKE OF METAL-IONS BY A NEW CHELATING ION-EXCHANGE RESIN .5. THE EFFECT OF SOLUTION MATRIX ON ACTINIDES

The influence of commonly occurring matrix constituents on the uptake of representative actinides in the tri-, tetra-, and hexavalent oxidat ion states by a new chelating ion exchange resin, called Diphonix(TM), has been investigated. The effect of increasing concentrations of HF at three fixed HCl concentrations on the retention of U(VI), Np(IV), a nd Am(III) was measured. All three actinides showed strong retention i n HF even up to a concentration of 1 M. The effect of sulfuric, oxalic and phosphoric acids at three fixed HNO3 concentrations on the retent ion of Th(IV), U(VI), and Am(III) was also measured. Only when the con centration of the complexing acids was above 0.1 M was the retention o f the actinides decreased significantly at 0.1 M HNO3. The effect was much less pronounced at higher HNO3 concentrations. Sodium, calcium, a luminum and iron were selected to study the influence of cationic matr ix constituents on the uptake of actinide ions by Diphonix. In the cas e of tetra- and hexavalent actinides (represented by Th and U, respect ively) only the very highest concentrations of Fe(III) and Al(III) cau sed a significant decrease in the retention of the two higher valent a ctinides. On the other hand, Am(III) retention was significantly lower ed by Al and Fe(III) concentrations above 10(-2) M. The influence of A l and Fe(III) on the uptake of Am(III) may be minimized by use of fluo ride ion to complex Al and by reducing Fe(III) to Fe(II). Macroconcent rations of sodium and calcium had only minimal influence on the uptake of actinides in all three oxidation states.