Microenvironment-Modulating Adsorption Enables Highly Efficient Lithium Extraction under Natural pH Conditions

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Ion-sieve adsorbents are crucial for lithium extraction but suffer from low capacity and selectivity in natural waters.
• Interference from H+ and Mg2+ ions in seawater/salt lakes significantly suppresses adsorbent performance.
• Existing methods often require substantial alkali addition, increasing costs and environmental impact.

Purpose of the Study:

• To develop a microenvironment-modulating adsorbent for efficient lithium extraction under natural conditions.
• To improve the adsorption capacity and Li/Mg selectivity of ion-sieve materials.
• To reduce the alkali consumption associated with lithium extraction processes.

Main Methods:

• Designing an adsorbent with quaternary ammonium groups to modulate the local microenvironment.
• Utilizing quaternary ammonium groups to accelerate H+ migration and electrostatically repel Mg2+.
• Incorporating OH- storage to neutralize in situ generated hydrogen ions.

Main Results:

• The microenvironment-modulating strategy dramatically reduced alkali consumption to 1/144th of traditional methods.
• Adsorption capacity increased by up to 4 times compared to commercial adsorbents under natural pH.
• Selectivity (Li/Mg separation factor) improved by up to 33 times, demonstrating enhanced performance.

Conclusions:

• Microenvironment modulation is a feasible strategy for effective lithium extraction from challenging aqueous sources.
• The developed adsorbent offers superior performance and reduced operational costs for lithium recovery.
• This approach paves the way for next-generation high-performance adsorbents in resource extraction.