Dual super-amphiphilic modified cellulose acetate nanofiber membranes with highly efficient oil/water separation and excellent antifouling properties

Along with increasing oily, industrial wastewater and seawater pollution, oil spills—and their clean-up via the separation of oil and water—are still a worldwide challenge. Aiming to fabricate an oil/water separation membrane with excellent comprehensive performance, we report here a new type of multifunctional deacetylated cellulose acetate (d-CA) membrane. The cellulose acetate (CA) nanofiber membranes are fabricated by electrospinning and then deacetylated to obtain the d-CA nanofiber membranes, which are super-amphiphilic in air, oleophobic in water, and super-hydrophilic in oil. The multifunctional d-CA nanofiber membranes can be used as water-removal substances for oil/water mixtures, as well as emulsified oil/water and oil/corrosive aqueous systems, with gravity as the only needed driving force. The d-CA nanofiber membranes possess the highest separation flux, reaching up to 38,000 L/m²·h, and the highest separation efficiency, reaching up to 99.97 % for chloroform/water mixtures under the force of gravity. In fact, the separation flux was several times higher than that of commercial CA (c-CA) membranes. The excellent anti-pollution and self-cleaning abilities endow the membranes with powerful cyclic stability and reusability. The d-CA nanofiber membranes show great application prospects in chemical plants, textile mills, and the food industry, as well as offshore oil spills, to separate oil from water.