Intercalation of small molecules in the selective layer of polyamide nanofiltration membranes facilitates the separation of Mg2+/Li

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 487; p. 150659
• Main Authors: Li, Junwei, Fang, Long, Xu, Daliang, Zhang, Xi, Jiang, Lei, Zhu, Qingjuan, Chen, Qin, Jin, Pengrui, Volodine, Alexander, Dewil, Raf, Gui, Xiahui, Gao, Qieyuan, Van der Bruggen, Bart
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024
• Subjects: Aminomalononitrile (AMN); Lithium separation; Nanofiltration; Polyamide membrane; Positive charge; Aminomalononitrile (AMN); Nanofiltration; Lithium separation; Polyamide membrane; Positive charge
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2024.150659

[Display omitted] •Aminomalononitrile (AMN) was used to enhance Mg2+/Li+ separation of PEI-TMC membrane.•The interaction of AMN with Mg2+/Li+ ions and H2O were explored by Density Functional Theory.•Small-molecule embedded mechanism of permeance enhancement for nanofiltration membrane was proposed. In addressing lithium supply shortages driven by increased energy demand, nanofiltration membrane technology is crucial for recovering lithium from salt lake brines. Overcoming the challenge of achieving high selectivity for Li+ and water permeability in polymer nanofiltration membranes, this study proposes a simple approach using Aminomalononitrile (AMN) intercalation to modify polyamide layers. Density functional theory simulations predict AMN's superior selectivity and enhanced hydrophilicity. Stable intercalation of AMN between polyethyleneimine (PEI) molecules is demonstrated, synergistically enhancing water permeability and Li+ selectivity. The resulting PEI/AMN-TMC membrane exhibits exceptional Li+ selectivity and improved water permeability (13.1 L·m−2·h−1·bar−1), 2.9 times higher than traditional PEI-TMC membranes. Stable performance for over seven days, along with anti-scaling and anti-bacterial properties, underscores its practicality. This investigation sheds light on membrane structure regulation through small-molecule intercalation, offering insights into precise adjustments for enhanced water permeability and ion selectivity.