Superhydrophobic sponge with self-cleaning properties for continuous and efficient oil-water separation in harsh environment

The pollution of water bodies by oil-containing compounds is increasing. Therefore, new oil-water separation adsorbents are under constant development. In this paper, melamine sponges with three-dimensional flexible porous framework are used to prepare oil-water separation adsorbents. Using a convenient one-step impregnation coating method, the material (THS@MS) was prepared by directly alkylating melamine sponge with a Trimethoxy (1 H, 1 H, 2 H, 2 H-heptadecafluordecyl) silane solution in an acidic (pH=5.5) ethanol solution. The adsorbent was superhydrophobic and had a strong oil adsorption capacity, ranging from 62.03 g/g to 71.33 g/g for various oils and organic compounds. After 50 cycles of oil-water separation, the separation efficiency remained above 95 %. The sponge remained in the superhydrophobic range after multiple separation tests. At this point, the hydrophobicity angle dropped by only a small value of 157.88 ° (compared to 158.57 ° in the original THS@MS test). THS@MS could be used to treat emulsion separations and is highly resistant to strong acid and alkali solutions. Its superhydrophobic properties enhanced self-cleaning ability and provided excellent environmental adaptability. The sponge showed great promise for wide application in real industries.