Fabrication of TBO-PSPH/MXene composite membrane for high-efficiency Rhodamine B separation

Background:As a typical refractory cationic dyes, Rhodamine B (RhB), poses a significant challenge in aquatic environment. Methods:To address this issue, this study fabricated a novel TBO-PSPH/MXene composite membrane by covalently grafting the silane-based N-halamine poly[5,5-dimethyl-3-(3’-triethoxysilylpropyl)hydantoin](PSPH) onto the surface of MXene, followed by the intercalation of the polycyclic dye Toluidine Blue O (TBO) into MXene interlayers. The composite membrane was characterized by XRD, XPS, FT-IR, N 2 adsorption /desorption, AFM and FESEM. Signifiicant Findings:The results demonstrated that the intercalation of TBO significantly enhanced structural stability of the membrane as well as the incorporation of PSPH reduced the surface negative charges and improved hydrophilicity of the membrane. Separation experiments with a 15 mg/L RhB solution at pH 1 and room temperature (RT) demonstrated a high rejection of 97.3% and a water flux of 4.63 L/(m²·h·bar). Notably, the incorporation of 10% NaCl significantly enhanced membrane performance, elevating RhB rejection to 98.9% while increasing water flux to 6.29 L/(m²·h·bar). The separation mechanism is attributed to synergistic effects of electrostatic repulsion, size-sieving, steric hindrance, and adsorption. This work provides a promising strategy for developing high-performance MXene membranes for treating challenging dye wastewater under various conditions.