TA Modified PAN/PU Nanofiber Membrane with Excellent Strength for Oil/Water Separation

Efficient and stable treatment of oily wastewater has garnered significant attention from society. Nanofiber membranes, prepared by electrostatic spinning technology, offer advantages such as high porosity and a large specific surface area, making them widely applicable in oily wastewater treatment. However, conventional nanofiber membranes often suffer from drawbacks such as low strength and poor hydrophilicity, which hinder their further development. In this study, a high-strength and hydrophilic composite nanofiber membrane was successfully fabricated through electrostatic spinning of polyacrylonitrile (PAN) and polyurethane (PU), with tannic acid (TA) serving as a blending agent. The mechanical properties’ characterization revealed that the obtained modified composite nanofiber membrane exhibited a tensile strength of 6.42 MPa and an elongation at break of 132.52%. The addition of TA significantly enhanced the wettability of the composite nanofiber membranes. The PAN/PU-TA composite nanofiber membranes demonstrated impressive separation flux (up to 3176.75 L m −2 ·h −1 ) and separation efficiency (up to 99%) for various oil compounds. Moreover, the separation efficiencies for different types of oil-in-water (O/W) emulsions were consistently above 95.44%. In general, the utilization of TA for hydrophilic modification of PAN/PU composite nanofiber membranes not only enhanced the mechanical and wetting properties of the nanofiber membranes but also offered new insights into the modified nanofiber membrane process and electrostatic spinning technology. Graphical Abstract