Ionic Liquid-Based Extraction Strategy for the Efficient and Selective Recovery of Scandium

Area of Science:

• Green Chemistry
• Hydrometallurgy
• Separation Science

Background:

• Industrial effluents often contain valuable metals like scandium (Sc).
• Current Sc recovery methods rely on hazardous organic solvents, posing environmental and safety risks.
• Developing sustainable and efficient Sc extraction techniques is crucial for resource recovery.

Purpose of the Study:

• To develop a novel extraction system for selective scandium recovery from acidic industrial effluents.
• To investigate the use of ionic liquids (ILs) and phenylphosphinic acid (PPAH) as an alternative to traditional organic solvents.
• To understand the influence of IL structure, pH, and temperature on Sc extraction efficiency.

Main Methods:

• Systematic investigation of scandium extraction using various ionic liquids (ILs) and phenylphosphinic acid (PPAH).
• Evaluation of the effects of IL chemical structure (alkyl chain length), aqueous pH, and temperature on Sc extraction.
• Characterization of the extraction mechanism, including proton exchange and complex formation.

Main Results:

• Ionic liquids with longer alkyl side chains exhibited reduced Sc extraction due to self-aggregation.
• The IL/PPAH system demonstrated high Sc extraction efficiency over a broad temperature range (288 K to 318 K).
• Increasing aqueous pH significantly enhanced the extraction efficiency of Sc.
• The extraction mechanism was identified as proton exchange, forming a Sc(PPA)3 complex.

Conclusions:

• The developed IL/PPAH system offers a promising, greener alternative for selective scandium recovery from acidic effluents.
• The findings highlight the importance of IL structure and aqueous conditions (pH, temperature) in optimizing metal extraction.
• This approach contributes to sustainable industrial waste management and valuable metal resource utilization.