2D montmorillonite nanosheet layer modulated interfacial polymerization for enhanced Mg2+/Li+ separation performance from salt-lake brines by polyamide membrane
Interfacial polymerization (IP) is a common approach for preparing selective nanofiltration (NF) membranes for efficient lithium extraction from salt-lake brines, yet controlling the structure and thickness of the polyamide (PA) selective layer remains challenging. In this study, a two-dimensional montmorillonite (2D MMT) layer was incorporated into the IP process to regulate interfacial reaction behavior. The 2D MMT layer was conducive to enriching amine monomers and inhibiting diffusion rate, thereby resulting in a thinner PA selective layer and the reduced water transport resistance. At the same time, the increased density of amine groups on the membrane surface implied that the membrane has a higher positively charge, which is more favorable for the Mg 2+ /Li + selective separation. As-optimized 2D MMT modified PA membrane demonstrated a high Mg 2+ /Li + selectivity of 35.45, nearly 6 times as high as that of the bare PA membrane. In addition, the stronger hydrophilicity of the 2D MMT modified PA membrane effectively retarded contamination, contributing to the long-term operational stability of the membrane and prolonging service life. This work provides a versatile strategy for enhancing NF membrane performance by employing 2D clay nanosheets to modulate the IP process. As-modified 2DMMT-PA membrane is suitable for practical applications in sustainable lithium resource recovery.
危险品化学品经营许可证（带存储）