Facile fabrication of super-hydrophobic and super-oleophilic Ota-PDA-PU sponge for efficient oil/water separation

With the aggravation of environmental pollution caused by oil and chemical leakages, oil-water separation has attracted much attention from both academia and industry. In this paper, a cost effective immersion method based on the modification of polyurethane sponge has been developed in the application field of oil/water separation. Octadecanethio and polydopamine were used to grafted onto PU sponge which was roughened by etching method. The morphology, composition and surface properties of prepared Ota-PDA-PU sponges were characterized by various techniques. The characterization results of the modified sponge exhibited rough surface structure, excellent flexibility, and possessed super-hydrophobic characteristic with a high water contact angle (WAC) of 155 ± 1°. The as-prepared sponge displayed high absorption selectivity for different organic solvents and oils, the absorption capacity for sesame oil attained 40 times of its own weight. Meanwhile, the absorption selectivity has no decrease after 10 cycles of absorption-desorption process. More importantly, the as-prepared sponge could be used as a filter for oil-water separation.