Efficient water purification using stabilized MXene nanofiltration membrane with controlled interlayer spacings

Abstract

Nanofiltration membranes made of MXene, a two-dimensional (2D) material, hold great promise for water purification. However, the commercialization of these membranes is hindered by their well-known swelling problem, which reduces their size-sieving performance and service life. To overcome these challenges, this study presents a novel approach by combining positively charged chitosan (CTS) and negatively charged MXene to form CTS-MXene/polyacrylonitrile (PAN) membranes. The use of CTS in the preparation process leads to enhanced mechanical strength and extended service life due to the strong interaction forces between CTS and MXene. The CTS-MXene/PAN membranes have a fixed layer spacing of 14.33 Å, contributing to ultra-high separation efficiency with over 99% rejection of Congo Red (CR) and ultra-high flux of 715.3 L m-2h−1 at 0.4 MPa. Moreover, the membranes exhibit remarkable filtration efficiency for bovine serum albumin under a pressure of 0.5 MPa. The membranes also demonstrate excellent reusability, making them a cost-effective option for water purification. This study not only provides a simple and reproducible strategy for preparing MXene-based membranes but also offers potential for the industrialization of these membranes. The development of CTS-MXene/PAN membranes as a promising approach for nanofiltration membrane development could pave the way for future applications in water purification and other separation processes.