Development of a biomimetic polyvinylidene fluoride membrane with a lotus leaf-inspired structure for enhanced oil-water separation

Efficient oil-water separation is crucial for environmental protection and industrial wastewater management; however, existing separation membranes often lack durability and suffer efficiency loss over multiple cycles. This study introduces a bio-inspired polyvinylidene fluoride (PVDF) membrane with a hierarchical lotus leaf-like surface, designed to overcome these limitations by enhancing separation efficiency, operational stability, and reusability. A polyvinylidene fluoride/polyvinylpyrrolidone (PVDF/PVP) composite membrane was fabricated as a support, onto which PVDF/silicon dioxide (SiO2) micro-nanoparticles were electrostatically sprayed to create a micro-nano papillae structure. This was followed by in-situ polymerization of dopamine (DA), forming a poly- dopamine (PDA) coating that enhances hydrophilicity and underwater oleophobicity. Optimization experiments identified a 20-minute spraying duration as ideal, achieving uniform micro-nanoparticle distribution and maximizing water permeability, with a pure water flux of 14,321 L & sdot;m-2 & sdot;h-1. The PDA/M-P/S-20 membrane demonstrated over 99.9 % separation efficiency for various oil-water mixtures and maintained stable performance across 15 cycles with only a 2.1 % flux loss, a significant improvement over conventional membranes, which often experience rapid fouling and efficiency decline. Additionally, the membrane exhibited underwater oil contact angles above 140 degrees, confirming its excellent underwater oleophobicity and self-cleaning capabilities. This research highlights the critical role of biomimetic design and precise structural control in addressing the durability and reusability limitations of existing separation technologies, offering a scalable, sustainable solution for industrial applications in petrochemical processing and wastewater treatment.