A reliable filter for oil-water separation: Bismuth coated superhydrophobic/superoleophilic iron mesh

The coral-like bismuth coated iron mesh (BCIM) was fabricated via chemical etching, immersion replacement and anneal. The resulting sample exhibited remarkable superhydrophobic/superoleophilic property with water contact angle of 163° and oil contact angle almost 0°. Visually, the water and hexane droplet could separately roll off and penetrate into the BCIM surface. Various oil-water (hexane, benzene, toluene, kerosene, bean oil, chloroform, tetrachloride, and water) separations were performed to investigate the separating performance. The initial separation efficiency of hexane-water reached 98.7% and it could maintain over 96% after 20 runs. The BCIM could also act as a scavenger to eliminate the floating or underwater oil. Moreover, it exhibited marvel buoyancy, desired stability and wear resistance.