Solvent extraction of rare-earth ions based on functionalized ionic liquids

Area of Science:

• Materials Science
• Separation Science
• Green Chemistry

Background:

• Rare earth elements (REEs) are critical for modern technologies.
• Efficient and selective separation of REEs remains a significant challenge.
• Ionic liquids (ILs) offer tunable properties for advanced separation processes.

Purpose of the Study:

• To synthesize and characterize novel DEHP-based ionic liquids (ILs) as extractants for REE separation.
• To investigate the performance of these ILs in a [C(6)mim][NTf(2)] diluent system.
• To evaluate the enhanced extractability and selectivity for REEs compared to traditional methods.

Main Methods:

• Synthesis and characterization of three functionalized ionic liquids: [TBA][DEHP], [TOMA][DEHP], and [THTP][DEHP].
• Investigation of DEHP-based ILs as extractants for REEs in [C(6)mim][NTf(2)] and diisopropylbenzene (DIPB).
• Comparison of solubility and extraction efficiency with di(2-ethylhexyl)phosphoric acid (HDEHP).

Main Results:

• DEHP-based ionic liquids exhibited significantly improved solubility in [C(6)mim][NTf(2)] compared to HDEHP.
• Enhanced extractabilities and selectivities for rare earth elements (REEs) were achieved using the novel DEHP-based ionic extractants.
• The [C(6)mim][NTf(2)] system demonstrated superior performance with the new ILs.

Conclusions:

• The developed DEHP-based ionic liquids are effective extractants for REE separation.
• The use of [C(6)mim][NTf(2)] as a diluent enhances the performance of IL-based extraction systems.
• This study presents a promising comprehensive ionic liquid-based strategy for efficient REE separation and recovery.