Efficacy evaluation of the antifouling magnetite–PES composite membrane through QCM-D and magnetophoretic filtration performances

Abstract

This study presents the surface interactions and macromolecular properties of magnetic responsive polyethersulfone (PES) membranes in relation to their potent antifouling behavior. Polyelectrolytes, polyanion poly(sodium-4-styrene-sulfonate) (PSS) and/or polycation poly(diallyldimethylammonium chloride) (PDDA), were alternately adsorbed on the surface of a PES microfiltration membrane using the polyelectrolyte multilayer modification method. Subsequently, the magnetic responsive Fe3O4 functional layer was end-capped to the polyelectrolytes-assembled-PES membrane. By using a quartz crystal microbalance with dissipation (QCM-D), the viscoelastic properties (ΔD) and adsorption kinetics (Δf) of the adsorbed adlayers were investigated. The QCM-D results demonstrated an exponential growth of Fe3O4 nanoparticles on the polyelectrolytes-assembled-PES polymer. The changes in the dissipation factor (ΔD) show greater motional freedom of the deposited multilayers (PSS, PDDA and Fe3O4) on the surface of the PES, where the surface morphology for the PES–Fe3O4 membrane was elucidated using FESEM/EDS. In this study, the synthesized magnetic responsive PES–Fe3O4 membrane demonstrated significantly improved permeability and selectivity. The membrane was shown to have a higher resistance to fouling based on the actuation motions of the magnetic nano-colloid under an oscillating external magnetic field. Subsequent exposure to a twisting effect promoted the detachment of humic acid from the membrane.