Robust preparation of flexibly super-hydrophobic carbon fiber membrane by electrospinning for efficient oil-water separation in harsh environments

Conventional polymer filtration membranes suffer from low efficiency, easy fouling and serious degradation in harsh environments, due to its low chemical and separation stability. Herein, a flexible super-hydrophobic carbon nanofiber membrane (CFMHF) was prepared using electrospinning and subsequently fluorinated treatment. The zinc acetate (ZnAc) was introduced to form pores in carbon fibers during heat treatment, and the pore-forming mechanism was well discussed. As a result, the flexibility and specific surface area of the carbon fibers were increased. The CFMHFs exhibited excellent super-hydrophobicity (water contact angle, WCA = 155.9°), high oil flux (3590 L m−2 h−1) and excellent oil-water separation performance. Driven by gravity alone, the separation efficiencies of the CFMHFs for non-emulsified oil-water and emulsified water-in-oil mixtures were both more than 98%. More importantly, the as-prepared CFMHFs showed good stability in harsh conditions, including high or low temperature, strong acid and alkali solutions, organic solvents and salt solutions. This strategy has directive significance for designing high performance oil-water separation membranes.