Highly permeable and stable hyperbranched polyethyleneimine crosslinked AgNP@Ti3C2Tx MXene membranes for nanofiltration

Two-dimensional (2D) materials have proved their superiorities as building blocks for constructing high-performance nanofiltration (NF) membranes. Herein, we propose a novel MXene-based NF membrane with high water permeability and stability by intercalating Ag nanoparticles (AgNPs) into the laminar structure of Ti 3 C 2 T x MXene with hyperbranched polyethyleneimine (HPEI) crosslinking. The pure Ti 3 C 2 T x MXene membrane, the AgNP-intercalated Ti 3 C 2 T x MXene (AgNP@Ti 3 C 2 T x MXene) membrane and the AgNP@Ti 3 C 2 T x MXene membrane with HPEI crosslinking (HPEI-AgNP@Ti 3 C 2 T x MXene) were comparatively investigated regarding their physicochemical properties and NF performance. The prepared HPEI-AgNP@Ti 3 C 2 T x MXene membrane exhibited competitive water permeabilities (24.64–30.73 L·m −2 ·h −1 ·bar −1 ) and nearly 100% rejections for Congo red, methyl orange, methyl blue and Rhodamine B solutions for long-term operation. Moreover, the HPEI-AgNP@Ti 3 C 2 T x MXene membrane also showed excellent NF performance for MgSO 4 , MgCl 2 , Na 2 SO 4 and NaCl solutions with the rejections of 84.15%, 77.01%, 74.67% and 56.58%, respectively. The NF separation mechanisms for the HPEI-AgNP@Ti 3 C 2 T x MXene membrane were elucidated based on its unique physicochemical structure. These findings may offer novel insights into tuning the laminar structures of MXene-based NF membranes for enhanced water purification .