Versatile superhydrophobic sponge for separating both emulsions and immiscible oil/water mixtures

Much effort in resource recycling and recovery has been devoted to developing durable materials for separation, but their versatility for emulsions and immiscible oil/water mixtures was far from ideal. In this work, a superhydrophobic sponge (MS-EP-APT) was developed using asphaltene (APT), melamine sponges (MS) and polyethyleneimine (PEI) for demulsification and water-oil mixture separation. These three easily obtained materials came from either oil refinement residue or low cost chemicals. The surface wettability, chemical stability, and mechanical durability of the sponge were analyzed to determine its separation potential. This sponge exhibited great separation efficiency for immiscible oil/water mixtures (> 96.0%), surfactant stabilized water-in-oil (W/O) emulsions (> 96.0%) and anionic surfactant-stabilized oil-in-water (O/W) emulsions (> 98.0%). It demonstrated good reusability and salt tolerance even in seawater. The separation mechanisms were proposed to be related to the hydrophobicity, positive charge, and torturous channels of the sponge. These superior performances make our sponge a strong candidate for green manufacturing and engineering in resource recovery and environmental remediation.