A bioinspired fouling-resistant surface modification for water purification membranes

Surface deposition of polydopamine, PD, using facile aqueous-based chemistry at mild reaction conditions, was accomplished on reverse osmosis, nanofiltration, ultrafiltration, and microfiltration membranes. This surface treatment not only retained much of the membranes’ intrinsic pure water permeability, but also improved the fouling resistance of polypropylene microfiltration (MF), poly(tetrafluoroethylene) MF, poly(vinylidene fluoride) MF, poly(arylene ether sulfone) ultrafiltration (UF), polysulfone UF, polyamide (PA) nanofiltration, and PA reverse osmosis membranes, as measured using oil/water emulsion filtration. To demonstrate scalability of this approach, PD was applied to, and improved the fouling resistance of, membrane modules. Following PD deposition, membranes could be further modified by grafting fouling-resistant macromolecules, such as poly(ethylene glycol), to further improve fouling resistance of MF membranes.