Lithium Extraction by Electrodialysis: Effect of Co-Occurring Ions for Application in Brine Processing

Lithium (Li) is considered a critical material because of growing Li-ion battery demand and 90% of global production occurring in Australia, Chile, and China. Li-ion (Li + ) extraction from brine uses large areas for evaporation and precipitation. Membrane separation can extract lithium with minimal water losses. However, the effect of brine composition on Li + transport across different commercial membranes in electrodialysis (ED) separations remains a pressing knowledge gap. This study aimed to evaluate co-occurring ion effects (Na + , Mg 2+ , Ca 2+ ) on ED Li + extraction using different commercial membranes. Li + extraction performance was evaluated for varying current densities in binary solutions using a single-stack ED cell comprised of a standard anion exchange membrane and either a standard cation exchange (CEM), monovalent-selective CEM, or nanofiltration (NF) membrane. Li + selectivities were highest for the monovalent-selective CEM, followed by NF and then standard CEM. Monovalent contaminants remain an extant challenge for Li + extraction using all membranes tested. Selectivity factors for Li + over divalent cations reached 6.8 (S Li/Mg ) and 56.7 (S Li/Ca ) at 2.8 mA cm −2 for the monovalent-selective CEM. These divalent separation factors were achieved without Ca precipitation/fouling; Li + /Mg 2+ and Li + /Ca 2+ ratios increased from 0.5 in the feed (for both ions) to 5.0 and 3.5 in the permeate.