Hydrophilic modified polydopamine tailored heterogeneous polyamide in thin-film nanocomposite membranes for enhanced separation performance and anti-fouling properties

To meet the larger-scale freshwater demand, it is necessary to develop advanced thin-film nanocomposite (TFN) membranes with favorable separation performance and anti-fouling capacity. In this study, hydrophilic modified polydopamine nanoparticles (PDNPs) were synthesized by the co-polymerization of alkaline l-Arginine (Arg) with dopamine (DA). Subsequently, they were incorporated into the polyamide (PA) layer via in-situ interfacial polymerization (IP) to fabricate TFN membranes. The effect of different PDNPs loadings on the overall membrane physicochemical properties and performance was studied. The incorporation of PDNPs strengthened a heterogeneous network structure of the PA layer, with a denser front surface and loose interior structure. Compared to TFC-0 membranes, the optimal TFN-PDNPs-2 membranes demonstrated a water permanence of 4.33 L‧m−2‧h−1‧bar−1 (increased by 71.7%), a NaCl rejection of 98.4%, and an ultrahigh antibiotics (TCH) rejection of 99.9%. In addition, TFN membranes showed good stability under various conditions and enhanced anti-fouling properties. This work provides a useful guideline for designing advanced membranes for a wide range of water treatment applications.