Thin film nanocomposite nanofiltration membrane uniformly embedded with sulfonic Noria cages at high loading for elevated perm-selectivity and antifouling properties

Water perm-selectivity and membrane fouling are the major challenges faced by nanofiltration (NF) membranes. In this work, a thin film nanocomposite (TFN) membrane with excellent separation and antifouling performances was fabricated by uniformly doping S-Noria (sulfonic Noria, a macrocyclic molecule) in polyamide layer with high loading capacity. S-Noria synthesized by sulfonating Noria with taurine has smaller nanoparticle size of ~5.9 nm and better water dispersion compared with Noria. Therefore, the water permeability of the optimal S-TFN 0.75 membrane can be increased to 2.2 times and 3.4 times that of the Noria-TFN and control TFC membranes, respectively, while maintaining a comparable Na 2 SO 4 rejection of ~98 %. During the dynamic organic fouling tests, the S-TFN 0.75 membrane with higher surface hydrophilicity and surface capacity of sulfonic groups showed milder flux decay and better flux recovery than the control TFC membrane. In addition, the S-TFN 0.75 membranes could more effectively alleviate the membrane fouling exacerbated by “Ca 2+ bridging effect”. In conclusion, this study provides a reliable method for the fabrication of TFN membrane with a high load of S-Noria uniformly dispersed in the polyamide layer, solving the bottleneck problems of water perm-selectivity and membrane fouling. • The S-Noria has better dispersibility and smaller particle size compared with Noria. • Water permeability of S-TFN 0.75 membrane is increased to 2.2 times that of TFC membrane. • S-Noria can make the membrane specific surface area larger and the thickness thinner. • S-TFN membranes could alleviate the membrane fouling exacerbated by Ca 2+ bridging.