Novel Positively Charged Metal-Coordinated Nanofiltration Membrane for Lithium Recovery

作者：Li Wang, Danyal Rehman, Pengfei Sun, Akshay Deshmukh, Liyuan Zhang, Qi Han, Zhe Yang, Zhongying Wang, Hee‐Deung Park, John H. Lienhard, Chuyang Y. Tang · 发表于：ACS Applied Materials & Interfaces · 年份：2021 · DOI：10.1021/acsami.1c02252 · 被引用次数：156 · 研究领域：Membrane Separation Technologies、Extraction and Separation Processes、Membrane-based Ion Separation Techniques

Nanofiltration (NF) with high water flux and precise separation performance with high Li + /Mg 2+ selectivity is ideal for lithium brine recovery. However, conventional polyamide-based commercial NF membranes are ineffective in lithium recovery processes due to their undesired Li + /Mg 2+ selectivity. In addition, they are constrained by the water permeance selectivity trade-off, which means that a highly permeable membrane often has lower selectivity. In this study, we developed a novel nonpolyamide NF membrane based on metal-coordinated structure, which exhibits simultaneously improved water permeance and Li + /Mg 2+ selectivity. Specifically, the optimized Cu– m -phenylenediamine (MPD) membrane demonstrated a high water permeance of 16.2 ± 2.7 LMH/bar and a high Li + /Mg 2+ selectivity of 8.0 ± 1.0, which surpassed the trade-off of permeance selectivity. Meanwhile, the existence of copper in the Cu–MPD membrane further enhanced anti-biofouling property and the metal-coordinated nanofiltration membrane possesses a pH-responsive property. Finally, a transport model based on the Nernst–Planck equations has been developed to fit the water flux and rejection of uncharged solutes to the experiments conducted. The model had a deviation below 2% for all experiments performed and suggested an average pore radius of 1.25 nm with a porosity of 21% for the Cu–MPD membrane. Overall, our study provides an exciting approach for fabricating a nonpolyamide high-performance nanofiltration m...