Dual-shielded antibacterial thin-film composite membrane unifying ROS-mediated biocidal action and thermodynamic anti-adhesion for sustainable cooling water treatment

To alleviate the global water crisis, membrane technology is widely employed in cooling water reuse processes. However, excessive microbial growth induced by industrial waste heat leads to severe membrane biofouling. This study constructed a customized armor coating composed of tannic acid (TA), copper (Cu), and polyethylenimine (PEI) on a commercial membrane surface via a minimalist approach. The coating achieved superior eradication efficiency (>95 %) against planktonic bacteria through Cu²⁺-catalyzed reactive oxygen species (ROS) generation. The average adhesion force between the membrane and bacterial coaggregates decreased significantly from 11.5 nN to 7.58 nN following modification. Furthermore, extracellular polymeric substance (EPS) components exhibited significantly reduced adhesion propensity on the membrane surface. This is attributed to the robust hydration layer provided by the metal-polyphenol network (MPN), which substantially elevated the membrane's surface energy barrier and adhesion resistance. Long-term synthetic wastewater testing demonstrates that a robust dual-action anti-fouling mechanism ensures highly efficient biofilm suppression capability, effectively extending the lifespan of nanofiltration membranes. This work expands the application of MPN-based materials in the membrane field, providing a minimalist yet highly efficient and innovative paradigm for developing antibacterial membrane surfaces.