Nanorod-patterned microfiltration membrane for biofouling mitigation: Role of nanorod height

The development of membranes with effective biofouling resistance is crucial for advancing membrane technologies in water and wastewater treatment. In this study, we successfully developed a series of nanorod-patterned polyvinylidene fluoride membranes, and systematically investigated the effects of nanorod height on their physicochemical properties and antibiofouling behaviors. The modified membranes demonstrated enhanced hydrophilicity, decent water permeability and rapidly antimicrobial ability against Escherichia coli . Notably, the membrane with the highest nanorods of 408 nm (HH) reduced bacterial viability to 48.6 ± 2.5% relative to the pristine membrane within 10 min. The rapid effect was associated with the triggered production of intracellular reactive oxygen species (ROS) upon short-term contact with the nanorod-patterned surfaces by stimulating antioxidative systems. In long-term antibiofouling tests, the HH membrane achieved a flux recovery rate of 93.1 ± 3.3%, substantially higher than that of the control membrane (i.e., 77.5 ± 4.6%), mainly attributed to rapid antibacterial activity imparted by nanorod pattern and competing membrane basic properties. Differentially expressed proteins (DEPs) analysis and morphological observations revealed that initial bacterial inhibition stemmed predominantly from ROS-mediated physiological stress rather than immediate physical disruption. Our study provided a new dimension for design and long-term application of nanopatterned membrane in water and wastewater treatment.