Cost-effective one-pot surface modified method to engineer a green superhydrophobic sponge for efficient oil/water mixtures as well as emulsions separation

Herein, a superhydrophobic and superoleophilic melamine sponge is fabricated by immersing the original sponges in ethanol solution containing tannin acid and n-octadecylamine. Meanwhile, the reagents are more economical and eco-friendly than commonly superhydrophobic modified materials such as dopamine, graphene, and 1-dodecanethiol. By integrating the high porosity, superior elasticity, and mechanical stability of the raw sponge with the low surface energy of n-octadecylamine and their nanometer scale roughness, the modified sponge not only possesses superhydrophobic surface with the water contact angle of 154.8°, but also exhibits excellent adsorption performance (absorption weight ranging from 70 to 148 times of its own) and extraordinary recyclability. The treated sponge also have superb separation efficiency for oil/water mixtures and emulsions, 99.95% and 99.57%, respectively. Besides, the simple processing is easy to scale up. All the merits manifest that this superhydrophobic sponge is the desired candidate for handing oil pollution in the sea.