Eco-friendly, magnetic-driven, superhydrophobic sponge for oil/water separation and emulsion purification

Large amount of oil leakage and organic wastewater discharge have greatly harmed the natural environment and human health. Therefore, researchers urgently need an effective method to address this problem. Superwetting materials can provide people with a good way to solve the problem because of their special selective wettability. In this report, a kind of green, fluorine-free, durable and low-cost superhydrophobic magnetic sponge was prepared by Fe₃O₄ particles and stearic acid. It can be controlled by changing the magnetic field to avoid direct contact with toxic and harmful solvents by the operator. The prepared material can be soaked for 7 days under harsh conditions of an acid solution, an alkali solution and a salt solution, and still maintain superhydrophobic property. Moreover, it is loaded with a weight of 200 g for 80 cycles of extrusion deformation (the compressive strain is 75%), and then with superhydrophobic properties. The sponge can be used for the separation of oil–water mixtures and oil–water emulsion purification with a separation efficiency of over 90%. It is worth mentioning that crude oil emulsion can be separated and purified by this material. The magnetic superhydrophobic sponge is prepared by simple and easy-to-operate method, which can be prepared in large scale. These results provide useful avenue utilization for the sponge, demonstrating the potential applications for oil–water separation, sewage purification, emulsion purification and oil spill collection.