Rapid adsorption for oil using superhydrophobic and superoleophilic polyurethane sponge

Abstract

Abstract BACKGROUND Cleanup of oil spills is a worldwide task needed to avoid serious environmental pollution. Recently, polyurethane ( PU ) sponge has been used as an oil absorbent, however, its efficacy is limited by its hydrophilic property. RESULTS This work describes the modification of PU sponge with ZnO microrods and palmitic acid ( PA ). A coating of ZnO microrods made the surface of PU sponge rough, which improved the hydrophobicity and oil‐adsorption capacity of the sponge. Further immersion in PA solution reduced the surface energy, which enabled the rough surface to be superhydrophobic (water contact angle ( CA ) > 150°). The contact angles of water and oil on the prepared ZnO and PA modified ( ZnO‐PA sponge) sponge were 168.9° and 0°, respectively. Adsorption capacities of ZnO‐PA sponge varied between 33 and 44 g g −1 for different oil samples, which were higher than those of the non‐modified PU sponge (21–23 g g −1 ). Adsorption equilibrium for the adsorption process of ZnO‐PA sponge was achieved within tens of seconds. Additionally, the ZnO‐PA sponge showed excellent selectivity for oil over water, and high reusability. CONCLUSION These findings indicated that the superhydrophobic PU sponge was a promising oil adsorbent for large‐scale oil‐spill collection. © 2015 Society of Chemical Industry