Oil spills are by far among the most hazardous environmental disasters, cleaning up after which is extremely difficult, instigating a long lasting impact on the Earth. A lot of contemporary research is going into techniques that could separate oil from water.
A team at the State University of Ohio have hit a promising mark on one such technique. Inspired by nature itself, they have devised a stainless steel mesh that let’s water pass but retains oil.
Led by Professor Bharat Bhushan and Philip Brown, the team studied the natural mechanism by which water particles roll off of lotus leaves. Lotus leaves are covered with ultra small bumps which carry even smaller hairy strands that force water to bead up and roll off. These same bumps do not, however, affect oil. The team came up with a reverse formula that allows water to pass through, but retains oil.
To achieve this surface, a steel mesh was sprayed with a dusting of silica nano-particles, which created bumps on the surface. A layer of polymer containing an oil-repellent surfactant was then added to induce the oil capturing effect. The mesh is only a few hundred nano-meters thick in its entirety, making it easily usable.
In the lab, a mixture of oil and water was poured onto this mesh and it was observed that the oil was retained on top while the water seeped through. A paper has been published on the research at Nature Scientific Reports.
The team believes that this mesh can be produced at fairly cheap rates (less than a dollar per square!) as all component materials are inexpensive, and it will be a reusable product which increases its efficiency greatly. Production of mass sheets can be used to clean oil spills etc.
The team is nhow working on the idea to replace silica nano-particles with tiny nano-tubes (a thousand times smaller than a human hair) made from molybdenum disulfide, which is known to bind oil. Oil binders can thus replace oil repellent in the mesh for a more improved performance.
Source: The Ohio State University