Incorporating dual-defense mechanism with functionalized graphene oxide and perfluorosulfonic acid for anti-fouling membranes

Surface segregation method based on the collaborative self-assembly principle was proposed to construct anti-fouling membranes with fouling-resistant and fouling-release mechanisms (dual-defense mechanism). Graphene oxides (GO) functionalized with polyethyleneimine (PEI) and perfluorosulfonic acid (PFSA) were added simultaneously into the casting solution to prepare PVDF/PFSA/PEI-GO hybrid membranes through surface segregation along with phase inversion process. The PEI-GO of hydrophilicity and the PFSA of low surface energy were utilized as additives to incorporate dual-defense mechanism for anti-fouling membranes. Furthermore, the synergistic effect of PEI immobilized on GO and sulfonic acid groups on PFSA generated electrostatic interaction, improving the long-term stability of membranes in aqueous environment. In the oil/water separation performance experiments, PVDF/PFSA/PEI-GO-1% membranes exhibited the highest pure water permeability of 406.7 ± 15.6 L m −2  h −1  bar −1 , with flux decay rate ( DR t ) of 8.6%, and flux recovery rate ( FRR ) of 98.6%.