Interfacial engineering of melamine sponges using hydrophobic TiO₂ nanoparticles for effective oil/water separation

In this study, the surface modified TiO₂ nanoparticles have been synthesized with oleic acid and trifluoroacetic acid (TFAA) as surfactants. The as-prepared TiO₂ nanoparticles reveal small particle size with narrow distribution, excellent dispersibility and high hydrophobicity. By interfacial modifying the melamine sponge with the hydrophobic TiO₂ nanoparticle, the wettability of the modified sponge can be tailored to be superhydrophobic to water while superoleophilic to oils. Combining with the porous structure of melamine sponge and the excellent hydrophobicity of the coated TiO₂, the modified sponge exhibits large absorption capacity (up to 88.1 g/g for chloroform), good selectivity and high recyclability for a wide range of oils and organic solvents. The results indicate that the TiO₂ modified sponges may potentially be useful as next-generation oil adsorbent materials.