Fabrication of poly(vinylidene fluoride)/graphite heterogeneous porous carbon nanofiber composite mat by electrospraying method for efficient oil–water separation

The efficient separation of oil and water is significant in addressing oil–water pollution issues. In this study, we developed a poly(vinylidene fluoride)/graphite (PVDF/GE) multiscale heterogeneous porous carbon nanofiber composite mat (MHPCM) through a two-step electrospinning method for enhanced oil–water separation. The mat was prepared by incorporating PVDF nanospheres, GE flakes, and carbon nanofibers, taking advantage of their inherent oil-repellent and water-attracting properties. MHPCM-4 demonstrates superhydrophobicity (WCA≈154.1°) and superoleophilicity (OCA≈0°). The separation efficiency for 1–14 μm carbon tetrachloride-in-water emulsions exceeds 99.9%. After 25 cycles, MHPCM-4 maintains its oil flux at 92.25% of the initial value. Additionally, even after 25 cycles, MHPCM-4 retains a separation efficiency of 99.8% for immiscible oil-in-water mixtures and a separation efficiency of 99.7% for water-in-oil emulsions. Thus, this material has great potential for efficient oil–water separation in various circumstances.