Carbon Nitride Quantum Dot-Based Thin-Film Nanocomposite Membranes for Efficient Dye Removal

Nanofiltration (NF) has been widely studied as a promising approach for dye wastewater treatment. However, low water permeance and membrane fouling are still major challenges that most current NF membranes face. Herein, we developed a thin-film nanocomposite (TFN) membrane incorporating graphitic carbon nitride quantum dots (CNQDs) via a facile interfacial polymerization method. The introduction of CNQDs not only results in a thin and loose PA active layer that facilitates rapid water transport but also provides additional water channels via their triangular nanopores. As a result, the TFN membrane exhibits a significant increase in permeation flux (210%) while maintaining a high rejection of methyl blue (96%) compared to the pristine thin-film composite membrane. Moreover, the newly developed membrane demonstrates excellent antifouling properties for bovine serum albumin, humic acid, and lysozyme due to the synergistic effects of enhanced surface hydrophilicity and reduced surface roughness resulting from the CNQD incorporation. These findings highlight the great potential of CNQDs in designing TFN membranes with a high separation performance and antifouling properties for efficient dye removal.