Zirconium ion modified melamine sponge for oil and organic solvent cleanup

Hydrophilic melamine sponge is transferred into hydrophobic melamine sponge by immersing the commercial melamine sponge cubes into zirconium oxychloride aqueous solution and followed by a simple dry process. The hydrophobicity transformation is assigned to the complex bonds constructed by the Zr⁴⁺ ions and N atoms, thus reducing the surface polarity. The modified melamine sponge presents excellent absorption capacities toward various oils and organic solvents (70-181 g/g). Its contact angle with water can reach 130° or more, and displays good oil-water selectivity for both heavy oil and light oil. Besides, the sponge has stable chemical properties and good recyclability. This work presents a facile and low-cost method for fabrication of hydrophobic materials that might be used for the cleanup of oil spills.