A New Customizable Surfactant LLPS Strategy for Sustainable and Highly Efficient Radioactive Metal Ion Separation

Area of Science:

• Green Chemistry
• Separation Science
• Radiochemistry

Background:

• Traditional radioactive ion separation relies on organic solvents, posing environmental and waste disposal challenges.
• Developing sustainable and efficient methods for radioactive metal ion separation is crucial for nuclear waste management and resource recovery.

Purpose of the Study:

• To develop a novel, sustainable, and efficient liquid-liquid phase separation (LLPS) strategy for radioactive ion separation.
• To create a customizable extraction system that avoids volatile organic solvents and refractory radioactive waste.

Main Methods:

• Utilized liquid-liquid phase separation (LLPS) in two coexisting aqueous phases using sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB), and hexafluoroisopropyl alcohol (HFIP) (SCH-extraction system).
• Encapsulated commercial extractants within the LLPS platform and tuned selectivity via extractant choice and solution acidity.
• Investigated separation factors in simulated high-level liquid waste (HLLW) and proposed a thermodynamic model.

Main Results:

• Achieved high separation factors for UO2^2+ /Nd^3+ (2.33 × 10^4) in simulated HLLW, outperforming existing methods.
• Demonstrated tunable selectivity by adjusting system parameters.
• Identified a dual mechanism involving hydrophobic entrapment and electrostatic attraction driving the separation efficiency.

Conclusions:

• The SCH-extraction system provides a customizable, sustainable, and efficient alternative to traditional organic solvent-based extraction for radioactive ions.
• The developed LLPS strategy offers a promising approach for the separation of valuable radioactive metal ions and radioactive waste management.
• The proposed thermodynamic model offers rational design principles for optimizing the system for diverse separation applications.