Fabrication of novel polyethersulfone (PES) hybrid ultrafiltration membranes with superior permeability and antifouling properties using environmentally friendly sulfonated functionalized polydopamine nanofillers

Developing hybrid ultrafiltration (UF) membranes with high permeability and low fouling tendency is important for a wide range of wastewater treatment applications. Herein, we report the synthesis of novel environmental-friendly sulfonated functionalized polydopamine (SPDA) nanocomposite as a nanofiller for UF membranes. Firstly, mussel-inspired PDA nanoparticles (NPs) were synthesized based on oxidation and self-polymerization of dopamine monomer. PDA NPs were subsequently sulfonated with 3-mercapto-1-propane sulfonic acid (a thiol - with -SO3H group) through Michael's addition reaction to produce the SPDA nanofiller. Fourier transform infrared spectroscopy and zeta potential measurements verified the functionalization of the PDA. Hybrid UF membranes were then fabricated via the non-solvent-induced phase separation process (NIPS), using polyethersulfone (PES) as a matrix and SPDA nanofiller at different loading levels (0-4 wt%). The water contact angle values showed an increase in the hydrophilicity of the fabricated UF membranes. The water permeability and antifouling capability of the hybrid UF membranes were dependent on the nanofiller's loading quantity. At 1 bar feed pressure, the pure water flux of the 2 percent SPDA nanofiller membrane was 2.7 times higher than that of the pristine membrane. Foulant solutions have been used to determine the antifouling efficiency of the hybrid membranes using sodium alginate (SA), humic acid (HA) and bovine serum albumin (BSA). The antifouling properties of the PES membranes have been significantly improved by incorporating the SPDA nanofillers in accordance with the foulant rejection and flow recovery ratios. The results indicated that SPDA nanofillers have great potential to improve the permeability and antifouling properties of PES membranes. Capsule: High-flux and antifouling PES hybrid membranes fabricated using environmentally-friendly sulfonated functionalized polydopamine nanofillers.