Ultrahydrophilic\nInorganic Nanosheet-Based Nanofiltration\nMembranes for High Efficiency Separations of Inorganic Salts and Organic\nDyes

Two-dimensional (2D) inorganic nanomaterials have garnered\nextensive\nattention in the fabrication of inorganic nanofiltration membranes\ndue to their unique structures and properties. In this study, we developed\na facile process for fabricating large-scale ultrahydrophilic nanofiltration\nmembranes using layered titanate H<sub>1.07</sub>Ti<sub>1.73</sub>O<sub>4</sub>·<i>n</i>H<sub>2</sub>O nanosheets (HT-ns).\nA drying deposition process was used to fabricate HT-ns membranes\non a poly(tetrafluoroethylene) (TF) substrate. To enhance the bonding\nstrength between the substrate and the deposited HT-ns membrane, the\nsubstrate surface was modified with a Cu<sup>2+</sup>-adsorbed silane\nmonomolecular layer, connecting a negatively charged HT-ns membrane\nand a positively charged substrate surface. The fabricated HT-ns membrane\nexhibited an excellent rejection performance for inorganic salts and\ndye molecules. The ultrahydrophilicity of HT-ns membrane with a low\nwater contact angle of 31° results in an ultrafast water permeance,\nwhich is approximately 6 times higher than that of a simple graphene-based\nnanofiltration membrane. The results open a new avenue to a new category\nof ultrahydrophilic nanofiltration membranes.