H~＋－Na~＋－UO^（2＋）_2三元离子交换动力学研究

STUDY ON THE KINETICS OF ION EXCHANGE IN TERNARY SYSTEM OF H￣+-Na￣+-UO￣(2+)_2

用强酸性阳离子交换树脂研究了Ｈ￣＋－Ｎａ￣＋－ＵＯ￣（２＋）＿２三元体系的离子交换动力学。通过对实验数据的拟合，计算了各反离子的粒内扩散系数。将该三元体系的实验结果与二元体系的实验结果对比分析之后，得出了一些很有价值的结论。结果表明，溶液中三种反离子的扩散不是独立的，而是彼此有影响的。当用三个Ｎｅｒｎｓｔ－Ｐｌａｎｃｋ方程分别描述每一给定反离子的扩散通量时，方程只能近似地适用于三元体系。还报道了该三元体系各反离子的平衡选择系数。

The kinetics of ion exchange in the ternary system of H￣+-Na￣+-UO￣(2+)_2 is studied with strongacidic cation exchange resin. The valuable conclusions are made by comparing the experimentalresults in this system with that in binary systerm. The particle diffusion coeffieients for givencounter ion in the system are calcalated by simulating the experimental data. Results show thatthe diffusions of the three kinds of counter ions in the solution are interdependent.Therefore,thethree Nernst-planck equations can only be approximately applied to the ternary system wheneach of the equations is used to describe the diffusion flux of a given counter ion respectively. Theequalibrium selectivity coefficients of each counter ion in the system are reported.