Superoleophilic Ulva prolifera for oil/water separation: A repayment from the green tide

• Green tide brings huge amount of algae composed by Ulva prolifera.
• Superoleophilic/ultrahydrophobic algae are achieved by modification.
• As-modified algae can be used for oil separation from bulky water.

The green tide formed by the macro-algae Ulva prolifera has caused problems to human being society. Finding the application will afford an effective way to eliminate the negative impact of the massive biomass. Fibrous U. prolifera can be a candidate for oil separation from seawater–oil mixture, a catastrophe to environment and ecology resulted from the oil spillage and emission. In this study, for the first time, U. prolifera collected from the green tide of 2015 was modified with dodecyltrichlorosilane to enable hydrophobicity and superoleophilicity properties. Different techniques, such as scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy, were used for characterizing the algae morphology and composition. The surface modification enables the surface wettability change from hydrophilicity to hydrophobicity, leading to high affinity to oil phase instead of water. Therefore, the green tide formed by algae affords a massive resource for oil collection, and superoleophilic U. prolifera for oil/water separation is a repayment from the green tide.