As we approach the fifth anniversary of the Deepwater Horizon oil spill, scientists are still trying to develop better ways of removing oil from water. Now, researchers at The Ohio State University believe that they may be onto something. They've developed a stainless steel mesh that allows water to pass through, but that stops oil.
Created by a team led by Prof. Bharat Bhushan and Philip Brown, the mesh was inspired by the leaves of the lotus plant. Lotus leaves are covered in tiny bumps that are tipped with even tinier hairs, which cause water to bead up and roll off when it lands on the surface – oil, however, isn't affected in the same manner.
This structure was altered for the mesh, so that water wouldn't be affected, but oil would be repelled.
The scientists started by spraying a dusting of silica nanoparticles onto a fine steel mesh, to create bumps across its surface. They then applied a layer of polymer that contained molecules of an oil-repellent surfactant. The entire combined coating was just a few hundred nanometers thick.
In lab tests, when oil-laden water was poured onto a piece of the mesh, the water flowed through while the oil remained on top. The researchers now think that large nets made from the mesh could be used to gather crude oil from sea water.
Because all of the materials are fairly inexpensive, Brown believes that the nets could be constructed at a cost of less than a dollar per square foot – and of course, they could be reused once the captured oil was poured off into a container.
A paper on the research was recently published in the journal Nature Scientific Reports.
Source: The Ohio State University