Chitosan‐Integrated MXene‐Based Nanofiltration Membrane With High Permeability for Efficient Dye Wastewater Treatment

ABSTRACT Two‐dimensional MXene nanofiltration membranes hold the promise for sustainable and rapid wastewater treatment. Nevertheless, addressing the significant swelling issue of MXene membranes in water remains a critical challenge prior to their practical implementation. Herein, the negatively charged MXene‐based membrane is modified with positively charged chitosan (CS) at various MXene:CS mass ratios using a straightforward hybrid approach. The CS‐MXene is vacuum filtered onto an electrospun polyacrylonitrile (PAN) substrate to serve as a barrier layer, resulting in the creation of anti‐swelling CS‐MXene/PAN composite membranes characterized by exceptional mechanical strength, stability, and a loose structure. The synergistic interaction between the CS‐MXene layer and the PAN substrate imparts the resulting CS‐MXene/PAN membrane with superior low‐pressure nanofiltration performance. Specifically, at a MXene to CS mass ratio of 1:2, the membrane exhibits rejection rates of 99.83%, 99.04%, 99.93%, and 98.84% for alcian blue 8GX, Sirius red, Coomassie brilliant blue, Congo red, respectively, along with corresponding fluxes of 435.23, 244.71, 573.76, and 505.11 L m −2 h −1 at 0.2 MPa. The CS‐MXene/PAN membrane also demonstrates long‐term stability during dye wastewater treatment, with the permeate flux remaining at a high level. These characteristics make the CS‐MXene/PAN membrane a promising candidate for dye wastewater nanofiltration applications.