Construction of Lotus-Leaf Inspired High-Efficiency Polyvinylidene Fluoride/Fluorinated Polyurethane Based on Electrospinning/Electrospraying for Oil-Water Separation Membranes

Abstract

Oil-contaminated water is a global problem that degrades the quality of water sources and poses a threat to human health and many ecosystems. Oil spills and the discharge of oily industrial wastewater seriously damage ecological environments. Thus, research into high-efficiency, energy-saving oil/water emulsion separation membrane materials is of great significance. Inspired by the hydrophobic mechanism of lotus-leaf surface, we used electrospinning/electrospraying technology to construct oil/water separation membranes with a nanofiber/microsphere bilayer structure consisting of polyvinylidene fluoride (PVDF) and fluorinated polyurethane (FPU). The inclusion of microspheres not only endowed the membrane material with a bilayer composite structure but greatly improved the hydrophobicity of the fiber membrane, achieving water contact angles of 150.2° and 159.1° in air and oil, respectively. Furthermore, the novel biomimetic separation membranes exhibited impressive self-cleaning performance for water-in-oil emulsions and excellent oil/water separation performance: the surfactant-stabilized Span80/diesel/water emulsion in the oil/water separation test reached 24 800 L m^‒2 h^‒1 bar^‒1 with a separation efficiency of over 99.5%. Moreover, even after 50 cycles of use, the lotus-leaf bionic separation membranes maintained their excellent oil/water separation ability, meeting long-term recycling requirements. The oil/water separation and recycling performance of the lotus-leaf bionic separation membranes demonstrate their promising application in the field of oily wastewater treatment.