Highly efficient uptake of Europium (III) and Americium (III) from acidic feeds using extraction chromatography resins containing N,N,N’,N’-tetra alkyl diglycolamides with varying alkyl chain length in an ionic liquid

A comparative study on the uptake of Eu(III) and Am(III) was carried out using four extraction chromatography (XC) resins impregnated with constant weight of the tetra-n-pentyl diglycolamide (TPDGA) ligands, viz. tetra-n-hexyl diglycolamide (THDGA), tetra-n-octyl diglycolamide (TODGA) and tetra-n-decyl diglycolamide (TDDGA) along with C4mim·NTf2, a room temperature ionic liquid (RTIL), from nitric acid feed solutions. The uptake of Eu(III) was higher than that of Am(III) while the uptake trend with the four XC resins followed the order: TPDGA > THDGA > TODGA > TDDGA, which was opposite to the alkyl chain length attached to the DGA extractant. When constant moles of the extractants were used, the observed trend was TODGA > THDGA > TDDGA > TPDGA. Also, for all the four XC resins, the uptake of both Eu(III) and Am(III) ions increased with increasing nitric acid concentration. The uptake data with all the four resins were fitted into different kinetic and isotherm models which conformed to a pseudo-second order kinetics and Langmuir monolayer sorption isotherm. Furthermore, columns were prepared with these XC resins and were used to obtain breakthrough profiles using a feed solution containing 0.55 g/L Eu(III) in 3 M HNO3. Subsequently, the elution of the loaded metal ion from the column was accomplished with a strippant solution containing 1 M guanidine carbonate + 0.05 M EDTA in distilled water. Elution profiles for all the four resins showed sharp peaks with almost no tailing. © 2022