Kinetics of Ion Exchange of Zr/Sn(IV) Phosphonate-Phosphate Hybrid Materials for Separation of Lanthanides from Oxidized Actinides

摘要

The kinetics of ion exchange of Zr/Sn(IV) phosphonate-phosphate hybrid ion exchange materials have been studied with several types of ions of specific interest to nuclear fuel recycling including Nd3+ at 4.5 and 43 mM and NpO2+ at 2.9 mM spanning multiple HNO3 concentrations. In most cases, the equilibrium was reached in less than 12 h. The ion exchange behavior followed that of pseudo first-order adsorption with rates ranging from 0.430-4.10 h(-1) to 0.290-0.435 h(-1) for Nd3+ and NpO2+, respectively. A separation with both Nd3+ and NpO2+ present was performed, resulting in separation factors of 1.9-12, 1.7-6.6, and 2.0-5.7 at 1 x 10(-1), 1 x 10(-2), and 1 x 10(-3) M HNO3, respectively.