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Tuesday, 17 April 2012

Nanomachines to clean up oil spills in water

ICN Group Leader Arben Merkoci, Prof Joseph Wang at UCSD, and co-workers report in ACS Nano the development and testing of “microsubmarines” that remove oil from contaminated water.

The Lilliputian cargo vehicles run on hydrogen peroxide, reach speeds of up to 26 micrometres per second and can carry up to ten times their volume in oil.

ICN doctoral student Maria Guix and ICREA Research Professor Arben Merkoci, head of ICN's Nanobioelectronics and Biosensors group, have collaborated with Prof Joseph Wang at the University of California San Diego (UCSD) on the design, fabrication and testing of nanomachines that remove oil from contaminated water. They have just published their work in ACS Nano.

The devices, which the team has dubbed "microsubmarines", are based on tubular microengines coated with an extremely hydrophobic layer to which the oil attaches. The vehicles, shaped like hollow bullets, are propelled by bubbles generated from the oxidation of hydrogen peroxide in their interior.

Prof Merkoci and his colleagues constructed the submarines in three main steps. Firstly, a bilayer of poly(3,4-ethylenedioxythiophene) (PEDOT) and platinum is electroplated onto a polycarbonate template. Next, another bilayer, of nickel and gold (Ni/Au), is deposited over the first layer by e-beam lithography. At this point, the bare submarine is obtained, which is not yet capable of carrying oil. Lastly, the submarine is coated with dodecanethiol self- assembled monolayers (SAMs), whose extremely hydrophobic character enable oil capture at the water-oil interface.

The team studied the effects of submarine composition on vehicle speed and oil carrying capacity, finding optimal performance with dodecanethiol as compared to other alkanethiols of different chain length.

The researchers believe that their discovery holds promise for the development of new devices and methods to clean contaminated water, especially in the contexts of environmental disasters such as oil spills.

 

The article can be accessed here.