▎ 摘　　要

To achieve oil/water separation using both absorption and filtration regardless of the oil/water density relationship, the super-hydrophilic/underwater super-oleophobic graphene oxide coated melamine sponge (GO@MS ) and super-hydrophobic/super-oleophilic reduced graphene oxide coated melamine sponge (rGO@MS) were prepared via dip-coating of graphene oxide (GO) sheets onto melamine sponge (MS) and subsequent chemical reduction, respectively. The structures of the GO@MS and rGO@MS were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectra, and X-ray diffraction (XRD). Both GO@MS and rGO@MS can preserve their original wettability in harsh environments containing acidic, alkaline, saline, and hot waters. The GO@MS and rGO@MS show excellent capability for selective absorption of water and oil respectively, with high capacities of 72.3-136.5 g g(-1) and excellent recyclability. The compressed GO@MS and rGO@MS also exhibit high separation efficiency of about 99% and ultra-high permeation flux above 1.62 x 10(5) L m(-2) h(-)(1) for separating different oil/water mixtures containing light and heavy oils through filtration driven by gravity, respectively. Furthermore, a bidirectional separation setup assembled with the compressed GO@MS and rGO@MS was constructed, which demonstrates high efficiency for continuously separating different oil/water mixtures of any oil density.