Nanofiltration Membranes Modified with a Clustered Multiquaternary Ammonium-Based Ionic Liquid for Improved Magnesium/Lithium Separation

• DOI: 10.1021/acsami.2c03650
• Publication Date: 2022-07-06T16:43:14Z
• Authors: Faizal Soyekwo; Hui Wen; Dan Liao; Changkun Liu
• Keywords: Nanofiltration; Surface Modification

Lithium separation is of great significance to overcome the lithium supply shortage resulting from a heightened demand in energy sector. The low selectivity polymer nanofiltration membranes for extraction concentrated Mg/Li mixtures caused by miniaturized pore structures and weak unstable positive surface charges limits their practical implementation. To address charge strength stability, novel ionic liquid monomer, N1-(6-aminohexyl)-N1,N1,N6,N6,N6-pentamethylhexane-1,6-diaminium bromide (denoted as DABIL), first synthesized covalently anchored on pristine polyamide thin-film composite (TFC) membrane via secondary amidation reaction improved selective mixtures. DABIL modification network contributes increased hydrophilicity, an enlarged structure, reinforced Donnan exclusion effects. Molecular dynamics simulation confirmed that difference interaction energies between water multication groups dominates properties. exhibits sixfold enhancement permeability compared unmodified outperforms recently reported state-of-the-art positively charged membranes. It presents Li+/Mg2+ 26.49, suggesting membranes' potential recovery. Moreover, shows efficient antibacterial activity mitigating biofilm formation. We establish functionalization TFC with liquids containing side chains could be promising approach achieve sustainable permselectivity recovery critical metal resources.