Sodium alginate modified metal oxide nanoparticles as a desirable nanofiller for polyethersulfone membranes:...

Biopolymers offer significant advantages in water treatment applications. This study investigates polyethersulfone (PES) membranes enhanced with TiO₂ and Fe₃O₄ nanoparticles modified by sodium alginate (NaAlg), abbreviated as NaAlg@TiO₂ and NaAlg@Fe₃O₄, for the removal of diclofenac sodium salt (DCF) from water. The NaAlg biopolymer modification was achieved by wrapping the metal oxide nanoparticles. The mixed matrix membranes containing modified nanofillers were prepared via phase inversion method. Results showed that adding 0.1 wt% NaAlg-modified nanoparticles increased membrane water uptake from 44 % to 90 % and 80 %, respectively. The pure water flux was improved due to enhanced hydrophilicity and porosity, and the modified membranes exhibited better fouling resistance against oily water. The DCF removal efficiency improved from 45 % to 96 % and 94 % for the NaAlg@TiO₂ and NaAlg@Fe₃O₄ nanocomposite membranes, respectively. The negative charge of NaAlg contributed to higher DCF rejection at pH 6-7. These findings demonstrate that modifying metal oxide nanoparticles with NaAlg enhances the performance of PES membranes, improving their effectiveness in water treatment.