Enhanced-flux nanofiltration membrane based on innovative 3D-printed support layer embedded with TiO2 nanoparticles

In recent years, nanofiltration (NF) membranes have garnered significant attention for water treatment and reuse applications, owing to their high separation efficiency, surface charge characteristics, and other advantages. However, the conventional support layer structures in NF membranes exhibit high permeation resistance, limiting their overall performance. To address this issue, an ideal through-hole structural support layer effectively minimizes resistance to water infiltration. The advent of advanced high-precision 3D printing technology facilitates the fabrication of such structures. In this study, a support layer with a straight-through pore structure was fabricated using advanced high-precision 3D printing technology, and the PES-COOH active layer was attached to the surface of the support layer via hydrogen bonding, resulting in the PES-COOH@3DP NF membrane. This innovation substantially reduced the permeation resistance, thereby enhancing the permeation flux of the NF process. The permeability of the PES-COOH@3DP NF membrane reached 6.64 L·m −2 ·h −1 ·bar −1 , which is double that of the PES-COOH@UF NF membrane. By incorporating varying concentrations of TiO 2 nanoparticles (0.5 %, 1 %, 1.5 %) into the photosensitive resin material, a hydrophilic support layer doped with TiO 2 nanoparticles was printed using a 3D printer. This improved the NF membrane's hydrophilicity, thereby enhancing its permeation flux. When the feed solution contained 1000 mg·L −1 Na 2 SO 4 , the [email protected]  % TiO 2 3DP NF membrane exhibited a permeability of 8.56 L·m −2 ·h −1 ·bar −1 , 1.5 times that of the PES-COOH@UF NF membrane and 22 % higher than the commercial NF90 membrane, while retaining 98.76 % salt and demonstrating strong chlorine resistance. This study underscores the significant potential of advanced high-precision 3D printing technology, establishing it as a strong contender for next-generation NF membrane desalination development.