Fine‐Tuning 2D Heterogeneous Channels for Charge‐Lock Enhanced Lithium Separation from Brine

• Published in: Advanced science 2024-11, Vol.11 (41), p.e2406535-n/a
• Main Authors: Hao, Yaxin, Liu, Xin, Zhang, Yaoling, Zhang, Xin, Li, Zhan, Chen, Ximeng
• Format: Article
• Language: English
• Subjects: 2D membrane; Adsorption; charge‐lock; Efficiency; Energy consumption; fine‐tuning heterogeneous channels; Fourier transforms; Graphene; Interfacial bonding; Lithium; Membranes; Morphology; Nanofiltration; Permeability; Phase transitions; real brine separation; Scanning electron microscopy; Spectrum analysis
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202406535

The extraction of lithium (Li) from complex brines presents significant challenges due to the interference of competing ions, particularly magnesium (Mg2⁺), 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 ZnFe2O4/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 Mg2⁺ ions, thereby facilitating the effective separation of Li from Mg. This mechanism is driven by a charge transfer during the formation of ZnFe2O4/ZnO, rendering O atoms in Fe‐O bonds more negatively charged. These negative charges strongly interact with the high charge density of Mg2⁺ ions, enabling the charge‐locking mechanism and the targeted capture of Mg2⁺. 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 Mg2⁺ in real brine conditions, achieving a Li⁺/Mg2⁺ selectivity of 59.3, surpassing existing brine separation membranes. Additionally, this membrane demonstrates superior cyclic stability, highlighting its high potential for industrial applications. A new strategy for lithium extraction from complex brines uses Charge‐lock enhanced 2D channels made from porous ZnFe2O4/ZnO nanosheets. This approach selectively captures Mg2+ ions through a charge transfer mechanism, improving Li+/Mg2+ separation. Optimized with Ag+, the membrane offers high water flux, 99.8% Mg2+ rejection, and superior cyclic stability, making it ideal for industrial use.