The above is the electron microscope scanning of the corresponding microstructure of blank sponge and graphene-supported sponge magnified 500 times (left) and 3000 times (right) respectively. Figure a and b show that the skeleton of blank melamine sponge is smooth and interwoven, forming multistage micropore structure with pore size ranging from tens to hundreds of microns. Therefore, oil or organic solvents can freely pass through the internal pores; The cross-linked skeleton structure of the sponge can also effectively support the weight of the adsorbed oil, giving the sponge a larger oil absorption capacity. According to the surface wetting theory, the material surface wettability is related to surface roughness and chemical properties. Because the blank sponge skeleton surface is smooth and flat, and contains a large number of hydrophilic groups, the oil-water separation selectivity is poor. As can be seen in Figure c and d, a large number of clumped and irregularly distributed graphene coatings appeared on the surface of the skeleton structure of the graphene loaded sponge. After local amplification, it could be clearly seen that there were crumpled protrusions with micro or nano size attached to the pore wall, which greatly increased the roughness of the sponge.