Extraction behavior of trivalent lanthanides from nitric acid medium by selected structurally related diglycolamides as novel extractants

• Ten of DGA were synthesized and grouped into four series for comparison.
• The structures-reactivity of DGA towards lanthanides extraction was established.
• The extracted species of lanthanides with DGA were affected by HNO3 concentration.
• The main extracted species of Ln(III) from 1 M HNO3 by DGA are Ln(DGA)4(NO3)3.

The extraction affinity of trivalent lanthanides, Ln(III), from nitric acid medium has been explored using a series of ten structurally related synthesized diglycolamides (DGA) diluted with toluene. The structure-reactivity relationship with extraction of trivalent lanthanides as well as their atomic number was investigated. The extraction of nitric acid and selected lanthanide ions by N,N,N′,N′-tetradodeceyldiglycolamide (TDDGA), from nitric acid medium was studied in details. Distribution ratio of the trivalent lanthanide ions has been studied as a function of aqueous HNO3 concentrations, DGA concentration, and temperature. The stoichiometry of La(III), Nd(III), and Eu(III) was determined at different nitric acid concentrations by slope analysis of extraction data, and enthalpy change accompanied by extraction was also determined and reported in this work.