关键词: 离子交换, 同位素交换, 自扩散, 稀土

Abstract: In this paper the self diffusion of rare earth ion(Eu³⁺ ) in porous ion exchange resins D72 and D751 was studied by isotope exchange reaction. Applying Kataoka's bidisperse pore model, the intraparticle effective diffusivities D_e were resolved into a solid diffusivity D_g and a macropore diffusivity D_p. The results express that Kataoka's equations can illustrate the kinetic process of porous ion exchange resins. The experiments show that D_e, D_p and D_g all increase with the increase of reaction temperature and the self-diffusion activation energy of Eu³⁺ ion under the experimental conditions was calculated; the response D_p and D_g to temperature of D72 resin is more sensitive than that of D751; D_e, D_p and D_g of D751 resin is smaller than that of D72 resin; the diffusivity of Eu³⁺ ion in solution is larger than D_p, which leads to the conclusion that the diffusion of ion in the pore of ion exchange resin can not completely be equal to that in solution.

Key words: Ion exchange, Isotope exchagne, Self-diffusion, Rare earth