关键词: D72 resin, ion exchange, praseodymium (III), adsorption, kinetics, thermodynamics

Abstract: In this work, the feasibility of using a macroporous strong acid ion exchange resin (D72) as an adsorbent for praseodymium (III) was examined. The adsorption behavior and mechanism were investigated with various chemical methods and IR spectrometry. The results showed that the loading of Pr (III) ions was strongly dependent on pH of the medium and the optimal adsorption condition is in HAc-NaAc medium with pH value of 3.0. Adsorp-tion kinetics of Pr (III) ions onto D72 resin could be best described by pseudo-second-order model. The maximum adsorption capacity of D72 for Pr (III) was evaluated to be 294 mg•g?1 for the Langmuir model at 298K. The ap-parent activation energy, Ea, was 14.71 kJ•mol?1. The calculated data of thermodynamic parameters, ΔS? value of 100 J•mol?1•K?1 and ΔH? value of 8.89 kJ•mol?1, indicate the endothermic nature of the adsorption process, while a decrease of ΔG? with increasing temperature indicates the spontaneous nature of the adsorption process. Finally, Pr (III) can be eluted by using 1.00 mol•L?1 HCl-0.50 mol•L?1 NaCl solution and the D72 resin can be regenerated and reused. Thomas model was successfully applied to experimental data to predict the breakthrough curves and to de-termine the characteristic parameters of the column useful for process design. The characterization before and after adsorption of Pr (III) ions on D72 resin was conformed by IR.

Key words: D72 resin, ion exchange, praseodymium (III), adsorption, kinetics, thermodynamics