Facile synthesis of superwetting FeNi foam for oil/water separation

Superhydrophobic/superoleophilic Cu-loaded FeNi foam was successfully prepared via an in-situ hydrothermal approach and subsequent stearic acid modification. The introduction of long alkyl chain endows the surface with strong hydrophobicity. The micro and nano structure of copper coating on FeNi foam is precisely controlled by varying the concentration of copper salts, which further facilitates the structural hydrophobicity. The contact angle for water on the synthesized FeNi foam is similar to 157 degrees, and for oil it is similar to 0 degrees. The separation efficiency for various oil/water mixtures could maintain above 99.3% after 30 cycles, suggesting good stability and durability. Our current findings provide a facile, eco-friendly approach to fabricate metal surface with special superwetting behavior and may expand the application of metal foam in the field of wastewater treatment.