Rhamnolipid biosurfactant complexation of rare earth elements

Area of Science:

• Materials Science
• Environmental Science
• Biotechnology

Background:

• Rare earth elements (REE) are critical for modern technologies.
• Developing sustainable methods for REE recovery is essential.
• Biosurfactants offer potential as environmentally friendly agents.

Purpose of the Study:

• To investigate the interaction between monorhamnolipid biosurfactants and REE.
• To establish a basis for a novel REE recovery technology.
• To quantify the binding strength of monorhamnolipids with various REE and metals.

Main Methods:

• Resin-based ion exchange chromatography was employed to measure conditional stability constants (log β).
• A comparative analysis was conducted using existing data for 10 other metals.
• Mixed metal studies and selectivity coefficients were used to assess preferential binding.

Main Results:

• Monorhamnolipids exhibited strong binding with all investigated REE (log β ranging from 9.82 to 8.20).
• Metals were categorized into weakly, moderately, and strongly bound groups based on log β values.
• Monorhamnolipids demonstrated preferential complexation of metals with higher log β values.

Conclusions:

• Monorhamnolipid-REE complexation presents a promising green pathway for REE recovery.
• This biosurfactant-based approach could be applied to non-traditional REE sources.
• The quantified binding affinities provide a foundation for optimizing REE separation processes.