SORPTION BEHAVIOR OF PERRHENATE AND OXOCHROMIUM(VI) ON REILLEX(TM)-HPQ ANION-EXCHANGE RESIN FROM NITRIC-ACID SOLUTION

The distribution coefficients (K'(d)) are reported for perrhenate and oxochromium(VI) ions on the nitrate form of Reillex(TM)-HPQ anion exchange resin as a function of nitric acid concentration. Maximum loadings of <5.1 equivalent % were used. K'(d) is defined by the following equation where M(total) is the total mmol of metal ion added and (M(sol)) is the analytical molarity of metal ion in V-sol mL of solution. The values of K'(d) for perrhenate at 10.0, K'(d) = M(total)-(M)(sol) x V-sol/mass of dry resin/(M)(sol) x V-sol/V-sol ml/g 5.00, and 1.00 M HNO3 are 5.00, 16.9, and 186 ml/g dry resin, respectively. The average value of K'(d) for oxochromium(VI) between 10.0 and 4.0 M HNO3 is 1.21 +/- 0.23 ml/g dry resin. At 1.0 M HNO3, the value is 1.80 ml/g dry resin. The behavior of the perrhenate system can be best described by assuming that the acid, HReO4, is formed with a derived acid dissociation constant of 2.32 M. The behavior of the oxochromium(VI) system is more complex. It is described phenomenologically by a simple inverse [HNO3] dependence.