Preparation of Highly Antibacterial MXene Nanofiltration Membranes and Investigation of Their Separation Performance.

In this study, polyethersulfone (PES)/sulfonated polyethersulfone (SPES) composite nanofiltration membranes doped with different contents of monolayer titanium carbide nanosheets (TiCT) were prepared by the nonsolvent induced phase inversion (NIPS) method. The effects of TiCT on membrane structure, separation performance and antibacterial activity were investigated systematically. The results demonstrated that the viscosity of the casting solution increased significantly with the increasing content of TiCT. In addition, the pore size of the membrane surface first decreased and then increased; porosity and hydrophilicity were optimized synchronously; and the density of negative charges on the surface increased. The M2 membrane showed a rejection rate of more than 90% for Metanil yellow (MY) and methylene blue (MEB). The order of salt ion rejection rates was magnesium sulfate (MgSO) > sodium sulfate (NaSO) > sodium chloride (NaCl), and water flux reached the peak (18.5 L/m·h·bar). The antibacterial activity of the M2 membrane was significantly enhanced, and its antibacterial rate against increased from 15% (M0) to 58%. This phenomenon was attributed to the synergistic mechanism of the TiCT physical capture effect, reactive oxygen species (ROS) generation and sharp edge damage to bacterial cell membranes. This study provides theoretical support and a technical path for the development of MXene composite membranes with high separation efficiency and excellent antibacterial properties.