Mussel-inspired zwitterionic dopamine nanoparticles as building blocks for constructing salt selective nanocomposite membranes

Nanocomposite membranes have gained growing attention in various application fields, especially in the separation and purification of resource substances. However, the nanomaterials and their membranes fabrication strategies usually suffer from complex procedures, high-energy consumption and lack of universality. Inspired by the unique self-polymerization and adhesion characteristic of marine mussels, we proposed a facile and versatile approach to synthesize zwitterionic dopamine nanoparticles via dopamine induced oxidative polymerization method, followed by the interfacial cross-linking on porous supporting layer to fabricate thin-film nanocomposite (TFN) membranes. The influences of nanoparticle composition, particle size and loading content on the membrane structure and performance were studied to optimize the fabrication conditions. The resultant TFN membrane exhibited high water permeance (98.0 L m(-2) h(-1) MPa-1) and good selectivity for di-/mono-valent salts (S-Na2SO4/NaCl = similar to 4.50, S-MgSO4/NaCl = similar to 4.49). Furthermore, by utilizing the protein, polysaccharide, and humic acid as model foulants, the zwitterionic dopamine nanoparticles based TFN membranes have been demonstrated with excellent fouling resistance and cleaning recovery property in separation applications.