Sm/Co Magnetic Materials: A Recycling Strategy Using Modifiable Hydrophobic Deep Eutectic Solvents Based on...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Hydrophobic deep eutectic solvents (HDES) are effective extractants.
• Typically, the role of the second component in HDES preparation is considered inert, neglecting its influence on extraction.
• This study investigates the impact of the hydrogen bond donor on HDES properties.

Purpose of the Study:

• To demonstrate the control of HDES selectivity by modifying the hydrogen bond donor.
• To explore the influence of the 'inert' component on HDES physicochemical and extraction properties.
• To evaluate the potential of tailored HDES for separating critical metals from waste.

Main Methods:

• Experimental analysis of HDES properties.
• Spectroscopic characterization.
• Computational modeling.
• Extraction experiments using phenol, para-tert-butylphenol, and thymol as hydrogen bond donors with trioctylphosphine oxide (TOPO).
• Separation of samarium (Sm) and cobalt (Co) pairs.

Main Results:

• The structure of the hydrogen bond donor significantly influences the extraction ability of TOPO-based HDES.
• Extraction efficiency for Sm(III) increased in the order: thymol:TOPO < para-tert-butylphenol:TOPO < phenol:TOPO.
• Physicochemical and extraction properties of HDES were confirmed to be affected by the 'inert' component.

Conclusions:

• The selectivity of trioctylphosphine oxide (TOPO)-based hydrophobic deep eutectic solvents can be effectively controlled by the choice of hydrogen bond donor.
• HDES composed of TOPO and phenols show promise for separating samarium and cobalt from hydrometallurgical process leach solutions of waste SmCo magnets.