Scaling‑free electro‑membrane crystallization enabled by electric field-assisted organic acid control

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Mineral scaling, caused by concentration polarization, hinders electro-membrane processes for recovering metals from lithium-ion battery (LIB) leachates.
• Existing methods struggle to prevent membrane fouling while simultaneously recovering valuable metals.

Purpose of the Study:

• To elucidate the synergistic mechanism of mineral scaling in electro-membrane systems.
• To propose and validate a novel electric field-assisted organic acid control (eF-OAC) principle for scaling prevention and metal recovery.

Main Methods:

• Dynamic experimental analysis to observe scaling at membrane interfaces and pores.
• Density functional theory (DFT) calculations to assess ligand-metal coordination preferences.
• Optimization of electro-membrane crystallization with the eF-OAC principle.

Main Results:

• Concentration polarization enriches metal hydroxides, driving scale formation.
• Organic ligands show a thermodynamic preference for coordinating metal hydroxides over sulfonate groups.
• The eF-OAC method achieved high recovery rates for Li (97.6%), Ni (95.3%), Co (94.2%), and Mn (97.8%).
• High-purity products were obtained: Li2SO4 (99.4%), Ni(OH)2 (99.2%), Co(OH)2 (99.0%), and Mn3O4 (99.3%).

Conclusions:

• The eF-OAC principle effectively prevents mineral scaling by dissolving scale and mobilizing metals.
• This method transforms scaling 'liabilities' into valuable resource recovery from spent LIBs.
• The study provides a scaling-free approach for efficient and selective metal recovery using electro-membrane technology.