One-Step Dipping Fabrication of Fe₃O₄/PVDF-HFP Composite 3D Porous Sponge for Magnetically Controllable Oil-Water Separation

Industrial oil spills in various bodies of water is a worldwide environmental problem that requires effective oil absorbents with remote controllability, which would be a clear improvement upon currently used technologies. One approach for adding remote controllability is embedding magnetic particles into the oil absorbent materials; however, there are currently few reports of magnetic oil absorbents. Most of these are prepared through multistep processes or using hazardous materials, which inhibits their practical use. In this study, we introduce a single-step dipping method to simultaneously provide both magnetic and hydrophobic/oleophilic functions to melamine foam by combining hydrophobic flexible copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and magnetic Fe₃O₄ nanoparticles synthesized by a method suitable for mass production. The as-fabricated coating performs effectively for oil collection of oil spilled on water, and the movement of the foam on the water's surface can be effectively controlled under magnetic field without touching it directly. Also, the coating is capable of regenerating its oil-absorbing property by being wrung out after the initial absorption owing to its flexibility and separation of oil in a water-in-oil emulsion. Such a simple method for the creation of multifunction material could potentially be helpful for the development of commercial remediation materials.