High-flux, antifouling and highly hydrophilic tight ultrafiltration membranes based on crosslinked PEEKWC/PEI containing positively charged water channel for dyes removal

For the removal of textile dyes, an effective alternative to fabricate tight ultrafiltration membrane was adopted. A series of tight ultrafiltration membranes based on PEEKWC/PEI covalent crosslinking structure were prepared by phase inversion method and showed high-flux and good antifouling performance attributed to the enhancement of hydrophilicity by PEI. The top-surface of the UF membranes was with a water contact angle in range of 24.33° and 40.10° indicating the excellent hydrophilicity. These membranes containing PEI-based positively charged water channel showed high permeability for pure water and salt solutions. As the content of PEI in membrane reaching 20 wt%, the pure water permeability and pure water flux at 3 bar could reach 308 L·m−2·h−1·bar−1 and 925 L·m−2·h−1, respectively. The pure water flux could even reach 1526 L·m−2·h−1 at 5 bar. At the operation pressure of 3 bar, all the UF membranes showed good single-component BBR rejection between 94.87 % and 97.73 %. The rejection of membranes for BBR in dye/salt mixtures was substantially higher than 94.0 % even at a high salt concentration of 60 g/L. The UF membranes with high-flux of pure water and dye solution were discussed, which could be a promising alternative for sustainable textile wastewater treatment and natural water recovery.