Microvolume Screening of Extraction and Phase Behavior in a Liquid-Liquid Microsystem

Area of Science:

• Chemical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Third-phase formation during liquid-liquid solvent extraction poses significant industrial challenges.
• Current methods lack the ability to simultaneously monitor extraction progress, third-phase onset, and the chemical/physical properties of the phases.
• Understanding complex phase behavior is crucial for optimizing extraction processes.

Purpose of the Study:

• To introduce a novel microfluidic strategy for real-time analysis of third-phase formation in solvent extraction.
• To correlate the visual onset of third-phase formation with extraction efficiency and loading limits.
• To enable spectroscopic characterization of the formed third phase.

Main Methods:

• Development of a microfluidic device featuring a submicroliter organic-phase film within a micropillar array.
• Extraction of Ytterbium (Yb3+) and Dysprosium (Dy3+) using 1 M Cyanex 572 in Shellsol D70 from an acidic aqueous phase.
• Real-time optical tracking of phase behavior and spectroscopic analysis of the third phase.

Main Results:

• The microfluidic setup successfully supported an optically transparent organic film.
• Real-time optical tracking demonstrated that third-phase formation coincides with the cessation of metal ion extraction.
• Spectroscopic analysis provided insights into the chemical and physical nature of the solid-like third phase.

Conclusions:

• The presented microfluidic approach offers a significant advancement for studying reactive multiphase systems.
• This method enhances the speed and efficiency of reagent development and process control in solvent extraction.
• It provides a powerful tool for fundamental investigations into complex phase behavior.