Superhydrophobic porous organic cage decorated melamine sponge for efficient oil-water separation

Frequent oil spills generate large amounts of oily wastewater, which severely harms the environment. The development of efficient oil-water separation materials is of great significance for both ecological environment management and resource recycling. Herein, a hydrophobic sponge composite (MS@POCs) with the water contact angle of 142° was successfully prepared by in-situ growth of trifluoromethyl-functionalized porous organic cage (CPOC-302-CF₃) on the surface of melamine sponge. The oil absorption capacity of MS@POCs for different oil substances was determined to be 62–123 mg/mg, and the adsorption performance remained unchanged after 15 adsorption-desorption experiments, demonstrating its good recoverability. More importantly, MS@POCs could effectively separate various oil-water mixtures and surfactant-stabilized water-in-oil emulsions with a maximum separation efficiency of 99.8%. This work presents a simple and effective method for fabricating hydrophobic sponges, which may also serve as a reference for designing other porous materials with high hydrophobicity.