Dispersant promotes mild formation of aminated-carbon quantum dots nanofiltration membranes for high-efficient resource recovery

Nanomaterial-based membranes are a research hot spot for their sub-nanometer structural precision that can realize selective separation within a molecular scale. However, their preparation needs complex processes (heat treatment, time-consuming, vacuum-assisted filtration, etc), restricting their development. For the first time, the dispersant-poly (maleic acid-co-acrylic acid) sodium salt (PMAS) was designed to promote the mild formation of amine-carbon quantum dots (CQDs-NH₂) membrane at room temperature via a facile interfacial polymerization. First, PMAS incorporation may form an electric double layer and strengthen the electrostatic force between CQDs-NH₂ and substrate, accelerating CQDs-NH₂ particle deposition. Second, the PMAS may be conjunct with the adjacent CQDs-NH₂ particles, lowing the long-range force, and improving CQDs-NH₂ particle deposition behavior. Third, its surfactant property may regulate the interface compatibility, improving the reactivity to promote the mild preparation of the separation layer. The prepared membrane possessed high water permeance (55 L/m²·h¹·bar¹) and high selective separation to the NaCl/reactive black 5 mixture, showing great potential for wastewater treatment and resource recovery.