Hydrophilic fouling-resistant GO-ZnO/PES membranes for wastewater reclamation

- Energy-efficient GO-ZnO membranes were developed using a facile two-step technique.
- Hydrophilic GO-ZnO membranes have improved pure water permeability.
- GO-ZnO nanohybrid reduces membrane-solute affinity interactions.
- Anti-fouling GO-ZnO membranes have high trace organic rejection properties.
- Novel GO-ZnO membranes have the potential to compete with commercial membranes.

Fouling of pressure-driven membranes remains a major challenge in membrane technology applications to wastewater treatment as it results in the deterioration of membrane performance. Several studies focusing on novel anti-fouling membranes incorporated with nanoparticles have been carried out but these membranes are not yet a viable solution due to their high energy requirements and poor trace organic compound (TOrC) rejection properties. Therefore, the aim of this study was to fabricate novel energy-efficient polyethersulfone (PES) membranes modified with graphene oxide - zinc oxide (GO-ZnO) and polyvinylpyrrolidone (PVP) for wastewater reclamation. A unique membrane synthesis approach called double-casting phase inversion (DCPI) was adopted. In this technique, the casting solutions are cast twice before coagulation. The addition of PVP and GO-ZnO increased membrane pure water permeability, hydrophilicity, and tensile strength while salt rejection increased slightly. The rejection of TOrCs and anti-fouling properties were also improved due to reduction in membrane-solute and membrane-foulant non-electrostatic or affinity interactions. These interactions were computed from contact angles of membranes, foulants and TOrCs based on the Lifshitz-van der Waals/acid-base approach. Compared to commercial NF-270 membranes under similar experimental conditions, the novel membranes exhibited higher fluxes, with less fouling and high rejection of TOrCs. Therefore, novel GO-ZnO membranes have the potential to compete with commercial membranes for wastewater reclamation.