Studies on ion exchange equilibria and kinetics: V. UO 2 2+ −Na+−H+ ternary cation exchange kinetics

The kinetics of particle-diffusion controlled ion exchange in the ternary system of cations UO₂²⁺–Na⁺–H⁺–001×7 strong acidic resin has been studied. In the [R–H⁺]/(Na⁺+UO₂²⁺) system, the change of the amount of Na⁺ in the resin phase with time showed a high peak. In the [R–Na⁺]/(H⁺+UO₂²⁺) system, the change of the amount of H⁺ in the resin phase with time also showed a high peak. In the [R₂–UO₂²⁺]/(H⁺+Na⁺) system, the change of amount of H⁺ in the resin phase with time showed merely a small peak. This kinetic character of the ternary ion exchange system in the finite solution volume has been analyzed according to the Nerst-Planck equation, and on the whole, the trend of the experimental results is consistent with the resulting numerical solution of the set of Nerst-Planck equations.