Study of uranium sorption using D2EHPA-impregnated polymeric beads

摘要

The extractant-impregnated polymeric beads (EIPBs), containing Di(2-ethylhexyl) phosphonic acid (D2EHPA) as an extractant and polyethersulfone as base polymer, were prepared by phase-inversion method. These beads were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) analysis to gain insight into the composition and morphology of beads. The beads exhibited good acid stability as no significant structural deformation or leaching out of the extractant was observed in 6M HNO_3 solution, up to the studied equilibration time of 15 days. The synthesized EIPBs were evaluated, for their ability to absorb uranium from aqueous solution, at different concentration and pH values. The kinetics measurement showed that about 90 min of equilibration time was enough to remove saturation amount of uranium from the solution. Kinetic modeling analysis of the extraction results was carried out using pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations and the corresponding rate constants were determined. The equilibrium data were fitted into different isotherm models and were found to be represented well by the Freundlich isotherm equation. Reusability of the beads was also established by multiple sorption-desorption experiments.