Using Diglycolamide Extractants in an Imidazolium-Based Ionic Liquid for Rare Earth Element Extraction and Recovery

Area of Science:

• Materials Science
• Green Chemistry
• Analytical Chemistry

Background:

• Growing demand for rare earth elements (REEs) necessitates sustainable extraction methods.
• Ionic liquids (ILs) offer tunable properties as alternatives to traditional organic solvents.
• Extractants like TODGA and DODGAA enhance selectivity and affinity for REE capture in ILs.

Purpose of the Study:

• To investigate the molecular interactions driving precipitate formation in IL-extractant systems.
• To explore the coordination environment of ytterbium (Yb3+) with DODGAA in an ionic liquid.
• To elucidate the role of hydrogen bonding in the observed precipitate.

Main Methods:

• Spectroscopic techniques (e.g., FTIR, Raman) to confirm precipitate composition.
• Computational studies to analyze coordination environments and binding affinities.
• Calculation of binding energies for Yb3+-extractant complexes.

Main Results:

• Precipitate formation confirmed between Yb3+, DODGAA, and [BMIM+][PF6-] ionic liquid.
• Spectroscopic analysis revealed hydrogen bonding between the [PF6-] anion's fluorine and the Yb-DODGAA complex's hydroxyl group.
• Computational studies indicated strong binding affinities of both DODGAA and TODGA for Yb3+.

Conclusions:

• Hydrogen bonding plays a key role in the precipitation mechanism.
• The strong binding affinity of DODGAA and TODGA explains their high efficiency in REE extraction.
• This research provides molecular-level insights into sustainable REE separation processes.