Desalination membranes with ultralow biofouling via synergistic chemical and topological strategies

Abstract

Biofouling is a persistent problem for desalination and water treatment membranes because it critically degrades membrane performance. Here, we report desalination membranes with ultrahigh biofouling resistance fabricated using a synergistic anti-biofouling strategy that combines topological and chemical antifouling modifications. Specifically, both the surface topology and the chemistry of desalination membranes were tailored by creating a biomimetic Sharklet pattern and integrating hydrophilic tannic acid and biocidal silver nanoparticles (AgNPs). The resultant membrane significantly enhanced biofouling resistance compared to the membranes modified by either the topological or chemical modifications alone due to the combinatorial antifouling effect. Importantly, the topological anti-biofouling effect was much more significant than the chemical effect under dynamic flow conditions due to the unique surface flows generated by the Sharklet geometry. Interestingly, the surface flow characteristics of the Sharklet pattern also effectively suppressed the leaching of the incorporated AgNPs and thus prolonged their anti-biofouling effect, highlighting the synergistic effect of the proposed combination strategy. This approach opens a new avenue for the fabrication of functional membranes, coatings and surfaces with superior antifouling and self-cleaning functions by elucidating the underlying antifouling mechanisms.