Fabrication of superhydrophobic electrospun polyimide nanofibers modified with polydopamine and polytetrafluoroethylene nanoparticles for oil–water separation

The oil–water separation technologies of removing oil pollutants from water in an efficient and economical way is a challenge. The current methods used for oil–water separation suffer many shortcomings, including a low separation efficiency, complex separation equipment, high operation costs, and secondary pollution. In this study, we fabricated a highly flexible, high-intensity, quite stable superhydrophobic and superoleophilic polyimide (PI) nanofibrous membranes, which are much more efficient and cost efficient for oil–water separation by modifying the membranes with a polydopamine (PDA) solution and polytetrafluoroethylene (PTFE) dispersion. The fabricated membrane (PDA–PTFE–PI) possesses both the high tensile stress of PI and the superhydrophobic and superlipophilic properties of the PDA–PTFE coating. The modified membrane could separate various oil–water mixtures efficiently at a high flux (6000 L·m⁻²·h⁻¹) and an extremely high efficiency (>99%). Furthermore, even when the membrane was under an extremely hostile environment (with an ultrahigh temperature, strong acidity, or strong basicity), it still remained quickly stable with a good separation efficiency and recyclability after 10 cycles. We anticipate that our study will provide a new technology for the highly efficient mass production of oil–water mixture management.