The fate of reverse micellar aggregation in irradiated diglycolamide inn-dodecane solution

Abstract

Diglycolamides (DGAs) are susceptible to organic phase splitting, known as the third phase formation, during the course of solvent extraction of trivalent metal ions from high-level liquid waste (HLLW). The...

Diglycolamic acid for the mutual separation of lanthanides and actinides from dilute nitric acid solution: solvent extraction, dynamic light scattering, and spectroscopic investigations

“…, into the organic phase increases the size of reverse micellar aggregates as these polar species occupy the core of reverse micelles, as discussed elsewhere. 31–36 The self-aggregation behavior of the organic phase composed of HDODGA and HD 2 DGA in IDA/ n -dodecane was studied using the dynamic light scattering (DLS) technique, and the results on the self-aggregate distribution of the organic phase are shown in Fig. 7.…”

“…Similar polar–polar interactions leading to the formation of reverse micellar aggregates are reported by several authors in solvent extraction systems. 31–36…”

“…The dynamic light scattering (DLS) technique is widely adopted for the determination of the average size of the reverse micellar aggregates and their distribution in a homogeneous organic solution. 31–35 The aggregates dispersed in an organic phase remain under constant Brownian motion causing fluctuations in the intensity of their scattered light. The average aggregate size and size distribution of these aggregates in the organic phase can be determined using the data on fluctuations of the intensity at a particular angle and using the Stokes–Einstein expression given in eqn (2).…”

“…Nevertheless, the tendency of reverse micellar aggregation in any organic phase usually increases with the increase in the extraction of nitric acid and metal ions in the organic phase, as discussed elsewhere. 31–36 Extensive aggregation of reverse micelles leads to either third phase formation or precipitation, which is an undesirable event in a solvent extraction process. Therefore, there is a need to understand the behavior of reverse micellar aggregation in the organic phase when diglycolamic acid is employed for the extraction of trivalent f-ions.…”

The fate of the organic phase beyond third phase formation

“…[7][8][9][10][11][12] As a result, the aggregate size and their distribution in the organic phase increases with an increase in the extraction of the acid and metal ion, as described elsewhere. [13][14][15] Extensive aggregation of reverse micelles in the organic phase results in the splitting of the organic phase into two phases. [11][12][13][14][15][16] The bottom of the organic phase known as the third phase or aggregate-rich phase contains the majority of aggregates, extracted metal, protonated ligand and little quantity of diluent, and the top of the organic phase known as the diluent-rich phase contains the majority of diluent molecules and a little quantity of metal ion and acid bonded ligand molecules.…”