Abstract
The extraction of lithium (Li) from complex brines presents significant challenges due to the interference of competing ions, particularly magnesium (Mg(2)⁺), which complicates the selective separation process. Herein, a strategy is introduced employing charge-lock enhanced 2D heterogeneous channels for the rapid and selective uptake of Li⁺. This approach integrates porous ZnFe(2)O(4)/ZnO nanosheets into Ag(+)-modulated sub-nanometer interlayer channels, forming channels optimized for Li⁺ extraction. The novelty lies in the charge-lock mechanism, which selectively captures Mg(2)⁺ ions, thereby facilitating the effective separation of Li from Mg. This mechanism is driven by a charge transfer during the formation of ZnFe(2)O(4)/ZnO, rendering O atoms in Fe-O bonds more negatively charged. These negative charges strongly interact with the high charge density of Mg(2)⁺ ions, enabling the charge-locking mechanism and the targeted capture of Mg(2)⁺. Optimization with Ag⁺ further improves interlayer spacing, increasing ion transport rates and addressing the swelling issue typical of 2D membranes. The resultant membrane showcases high water flux (44.37 L m⁻(2) h⁻¹ bar⁻¹) and an impressive 99.8% rejection of Mg(2)⁺ in real brine conditions, achieving a Li⁺/Mg(2)⁺ selectivity of 59.3, surpassing existing brine separation membranes. Additionally, this membrane demonstrates superior cyclic stability, highlighting its high potential for industrial applications.