Preparation of superhydrophilic polyimide fibrous membranes by electrostatic spinning fabrication for the efficient separation of oil-in-water emulsions

Membrane separation is considered an effective technology for treating oily wastewater. Hydrophilic, under-water oleophobic water removal membranes prepared by electrostatic spinning have received significant attention due to their excellent antifouling properties, small pore blockage, and high permeation flux. Herein, a simple and effective method was proposed for fabricating fabrics with superhydrophilic and submerged superoleophobic properties. First, the materials were co-blended with sodium dodecyl benzene sulfonate by electrostatic spinning, and then the porous fiber membrane was obtained by a step-up temperature for thermal imidization. The obtained membranes showed superhydrophilic and underwater oleophobic properties and could separate oil-water emulsions with or without surfactant stabilization while also exhibiting certain retention of methylene blue dye. The separation efficiency was driven by gravity alone, and the oil-water separation efficiency was always above 98.5% for 10 separation cycles, with a separation flux of up to 700 L center dot m(-2)center dot h(-1). The modified membranes were tested and evaluated for various oil-water emulsions, and the separation efficiency was found to be consistently above 98.5%. In addition, the membranes showed satisfactory mechanical strength, high-temperature resistance, and excellent contamination resistance, suggesting that these membranes could serve as promising candidates for the treatment of industrial oil-in-water emulsions.