Self-driven one-step oil removal from oil spill on water via selective-wettability steel mesh.

Marine oil spills seriously endanger sea ecosystems and coastal environments, resulting in a loss of energy resources. Environmental and economic demands emphasize the need for new methods of effectively separating oil-water mixtures, while collecting oil content at the same time. A new surface-tension-driven, gravity-assisted, one-step, oil-water separation method is presented for sustained filtration and collection of oil from a floating spill. A benchtop prototype oil collection device uses selective-wettability (superhydrophobic and superoleophilic) stainless steel mesh that attracts the floating oil, simultaneously separating it from water and collecting it in a container, requiring no preseparation pumping or pouring. The collection efficiencies for oils with wide ranging kinematic viscosities (0.32-70.4 cSt at 40 °C) are above 94%, including motor oil and heavy mineral oil. The prototype device showed high stability and functionality over repeated use, and can be easily scaled for efficient cleanup of large oil spills on seawater. In addition, a brief consolidation of separation requirements for oil-water mixtures of various oil densities is presented to demonstrate the versatility of the material system developed herein.