Highly efficient diglycolamide-functionalized dendrimers for the sequestration of tetravalent actinides: solvent extraction and theoretical studies

Abstract

Two diglycolamide (DGA) functionalized poly(propylene imine) diaminobutane dendrimers, first generation (Gen I) and second generation (Gen II), termed as LI and LII, were used for the extraction of the tetravalent...

Sequestration of tetravalent neptunium from acidic feeds using diglycolamide-functionalized dendrimers in a room temperature ionic liquid: extraction, spectroscopic and electrochemical studies

“…5(a) and (b)), suggesting a similar ligand environment around Np(IV) in both species in line with the speciation studies performed previously. 20 Although formation of 1 : 1 complexes was observed for Np(IV) extraction by L I and L II into the RTIL, their vis-NIR spectra were very different (Fig. 5(c) and (d)).…”

“…The 20 For both ligands the formation of 1 : 1 species was observed both in ionic liquid and molecular diluents, though the nature of the species is distinctly different. It is worthy to compare the UV-Vis spectra of the Np(IV)-L extracts from the two media to gain some more insight into the nature of the extracted species.…”

“…Most of the acid or water uptake is decided by the C 4 mimÁNTf 2 medium (Table 1). The extraction kinetics of Np(IV) for L I and L II dissolved in C 4 mimÁNTf 2 was found to be relatively slow as compared to the molecular diluent 20 and equilibrium was achieved in 30-40 minutes of equilibration (ESI). The preliminary studies showed a high D Np for L II compared to L I even at 1 Â 10 À4 M ligand concentration.…”

“…This difference may arise from the involvement of a lower number of nitrate ions present in the Np(IV)-L (L = L I or L II ) extracted complexes from C 4 mimÁNTf 2 as compared to those extracted from molecular diluent medium and also may be due to the presence of higher amounts of water/acid in the C 4 mimÁNTf 2 phase compared to that in a molecular diluent. 20 The relative position of various f-f transitions for the Np-L I and Np-L II complexes can be used to get information about the relative complexing strength of the ligands. 32,46,[53][54][55] The peak positions of the most intense transition of the Np-L I and Np-L II complexes are 966 AE 2 nm and 738 AE 2 nm, respectively.…”

“…2). 20 All these above studies used molecular diluents such as n-dodecane and its mixtures, which are considered hazardous due to their VOC contents. Room temperature ionic liquids (RTIL) are neoteric diluents extensively studied for metal ion extraction in view of their low volatility and nonflammability.…”