Three benzene-centered tripodal diglycolamide (Bz-T-DGA) ligands were evaluated for the pertraction of Am3+ across PTFE flat sheet membranes. The feed phase contained a tracer spiked nitric acid solution (3 M), while the receiver phase contained 1 M α-hydroxyisobutyric acid (AHIBA). The transport of Am3+ was quantitative with ligand LI, with ethyl groups appended to the benzene ring at the 1,3,5-positions and two spacer atoms between the ring and the DGA group. Ligand LIII, with a butoxy tether between the ring and the DGA unit, displayed a much better transport efficiency than ligand LII having an ethylamide linkage, although in both cases the transport rates are lower than that of LI. The transport efficiency of the actinide ions was Am3+ > Pu4+ ≫ UO22+ suggesting that Am and Pu can be easily decontaminated from U in a mixture. The membrane stability was reasonably good with LI, while it was poor for the other two ligands.
- Membrane transport
- Radioactive waste