Innovative Organic–Inorganic Hybrid Membrane for Oil-Water Separation via Chemical Bond Reconstruction-Enhanced Interfacial Polarity Reversal

Membrane separation technology, characterized by low cost and high efficiency, holds great promise for oil-water separation. Performance hinges on membrane polarity and pore size. Using electrospinning, PVDF nanofiber membranes with 300 nm pores is prepared. Then, the nanofibers are coated with a hybrid organic-inorganic polymer via chitosan-zirconium salt crosslinking. Introducing a novel chemical bond reorganization method, glutaraldehyde broke metal complex bonds, forming high-energy covalent bonds and exposing positively charged zirconium ions. This unique structure created a durable anti-oil barrier, enhancing interface polarity and water film formation. At an applied pressure of 0.02 MPa, the membrane achieved a pure water flux of 7828 L m⁻² h⁻¹ bar⁻¹ and an emulsion flux of 4280 L m⁻² h⁻¹ bar⁻¹. The membrane maintained stable flux performance throughout 100 hydraulic cycles and 30 oil/water emulsion separation cycles. Remarkably, this technology removes hard-to-filter light oil emulsions (like kerosene), achieving comprehensive oil-water separation, underscoring the importance of interfacial polarity and chemical reorganization in membrane development.