Semiconducting nanostructures for mopping up oil spills

Australian researchers have developed a multipurpose fabric covered with semiconducting nanostructures, which they say could one day be used to mop up oil spills.

The research team consisted of Dr Faegheh Hoshyargar and Associate Professor Anthony O’Mullane (QUT), Dr Louis Kyratzis and Dr Anand Bhatt (CSIRO) and Manika Mahajan, Anuradha and Dr Sheshanath Bhosale (RMIT). Their work was published in the journal ChemPlusChem.

As explained by Associate Professor O’Mullane, the team created the fabric from commercially available nylon that already had a seed layer of silver woven into it. They then dipped the fabric into a vat, where a copper layer was electrochemically deposited onto it.

With the copper coating now added, the researchers converted the fabric into a semiconducting material with the addition of a solution that causes nanostructures to grow on the fabric’s surface. These nanostructures are the key to the fabric’s enhanced properties, Associate Professor O’Mullane said — the means by which it is able to repel water and attract oil.

“The nanostructures are like tiny rods that cover the surface of the fabric,” Associate Professor O’Mullane said. “Water just runs straight off it, but the rods attract and hold oil.

“Also, when the fabric is saturated it allows the oil to permeate, where it then acts like a sieve to separate oil and water.”

The team has already tested the fabric and found it effective at cleaning up crude oil and separating organic solvents, ordinary olive and peanut oil from water. They were also able to mop up crude oil from the surface of fresh and salt water.

Associate Professor O’Mullane said the chemistry behind the creation of the new material was not complex, with all the steps in its production being easy to carry out. In principle, he said, production of the fabric could be scaled up to be used on massive oil spills.

“On a large scale, the material could mop up crude oil to saturation point and then be washed with a common organic solvent and re-used,” Associate Professor O’Mullane said.

Associate Professor O’Mullane described the fabric as “multifunctional”, saying its unique properties open up further applications beyond cleaning up oil spills.

“Its antibacterial properties arising from the presence of copper could be used to kill bugs while also separating water from industrial waste in waterways or decontaminate water in remote and poor communities where water contamination is an issue,” he said.

“Because it is also a semiconductor, it can interact with visible light to degrade organic pollutants such as those found in wastewater streams.”

The next step is to test the scalability of the approach and whether or not the material is mechanically robust, Associate Professor O’Mullane said.