Fluorine-Functionalized Covalent Organic Framework Superhydrophobic Modified Melamine Sponge for Efficient oil–water Separation

Hydrophobic sponges have attracted significant interest in oil spills and water-oil separation as potential absorption materials due to their desirable absorptivity, selectivity, and elasticity. In this paper, a hydrophilic melamine sponge (MS) is transferred into a superhydrophobic sponge via polydimethylsiloxane (PDMS) modification followed by in situ growth of fluorine-functionalized covalent organic framework (denoted as TFA-COF) nanoparticles. Therefore, the PDMS@TFA-COF@MS sponge was successfully prepared for efficient oil-water separation. The resultant PDMS@TFA-COF@MS exhibits superhydrophobic properties with a water contact angle of 156.7°. The superhydrophobic sponge has selectivity adsorption for different organic solvents and oils from water as well as oil-water separation efficiency (96% after 30 cycles) and oil absorption capacity (12 646% after 30 cycles). Meanwhile, the PDMS@TFA-COF@MS sponge exhibits strong thermal stability and flame retardancy in addition to having exceptional resistance to chemical corrosion in acidic, alkaline, and salt solutions. Moreover, the surfactant-stabilized oil-in-water emulsion could be efficiently separated by the sponge. Therefore, the prepared superhydrophobic PDMS@TFA-COF@MS sponge demonstrates possible uses for long-life oil-water separation applications.