Enhancing water flux and antifouling properties of PES hollow fiber membranes via incorporation of surface-functionalized Fe3O4 nanoparticles

BACKGROUND In this study, polyethersulfone (PES) hollow fiber membranes incorporated with surface-functionalized iron oxide (Fe3O4) nanoparticles were developed in order to improve water flux and antifouling properties of PES membrane. Commercial Fe3O4 nanoparticles was coated by polydopamine (PDA), followed by functionalization using (3-aminopropyl)triethoxysilane (APTES) and sulfonic acid to produce Fe3O4/PDA-Amine and Fe3O4/PDA-Sulf nanoparticles, respectively. All the nanoparticles-modified membranes were synthesized using dope solution composed of different nanoparticles, followed by a series of instrumental characterization and filtration assessments. RESULTS It is found that the membrane incorporated with Fe3O4/PDA-Amine exhibited the best filtration performance, achieving water flux of 137.23 L m(-2) h(-1) bar(-1) and bovine serum albumin (BSA) rejection of 92.16%. As a comparison, the pristine PES membrane only showed 82.60 L m(-2) h(-1) bar(-1) and 71.92%, respectively. The membrane with Fe3O4/PDA-Sulf also showed lower performance, recording 129.88 L m(-2) h(-1) bar(-1) and 88.39%, respectively. The improved performance of the Fe3O4/PDA-Amine-modified PES membrane could be attributed to its lowest water contact angle (65.10 degrees), highest porosity (68.14%), ideal pore size (65 nm) as well as good structural integrity. More importantly, the improved surface properties also led to outstanding fouling resistance, achieving flux recovery rate of 97%. This membrane also achieved excellent chemical oxygen demand (95.17%) and color (89.86%) reduction when tested using river water sample. CONCLUSION Our work demonstrated a simple approach to functionalize the surface of Fe3O4 nanoparticles and showed the effectiveness of the surface-functionalized Fe3O4 nanoparticles in improving not only the surface properties of PES membrane but also its filtration performance in terms of permeability, rejection and antifouling property. (c) 2021 Society of Chemical Industry (SCI).