Nanostructures can mop up oil spills

SEMI-CONDUCTING nanostructures grown directly onto water-repelling fabric can attract spilled oil and can degrade organic matter when exposed to light.

A research team, led by the Queensland University of Technology (QUT), in Brisbane, Australia used nylon fabrics that have had a seed layer of silver woven into it to help prime the fabric for the next step. The fabric was then dipped into a vat where a layer of copper was electrochemically deposited onto it.

The semi conducting properties of the copper coating, and the addition of a solution of a proprietary substance called TCNAQ that is dissolved in acetonitrile, causes nanostructures of CuTCNAQ to grow and intertwine with the surface of the fabric. The team says this is 'the key to its enhanced properties'.

Anthony O’Mullane, associate professor at QUT's School of Chemistry, Physics and Chemical Engineering, said: 'The nanostructures are like tiny rods that cover the surface of the fabric. 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 tested the fabric's ability to mop up crude oil in fresh and salt water. It can also separate organic solvents, and can be used domestically to clean olive or peanut oil from water. The team says on a large scale, the fabric can mop up oil until saturated, be recovered and washed with organic solvent and reused.

O'Mullane added that the chemistry of the fabric isn’t complex and could be scaled up easily. He said: 'All steps in its production are easy to carry out and, in principle, production of this fabric could be scaled up to be used on massive oil spills that threaten land and marine ecosystems.'

The semi-conducting properties of the fabric allow further applications such as in wastewater streams. It can interact with visible light to degrade organic pollutants, and the antibacterial properties from the copper coating would allow it to kill microbial bugs. The team says this approach can work in remote regions where water contamination is an issue for poor communities.

The next step will be to test if the material is mechanically robust enough to be scaled up for commercial use.

“Our testing has shown the material is chemically robust but we need to investigate whether the nanostructures can withstand tough wear conditions,' added O'Mullane.

The researchers used nylon in their experiments, however, they say any fabric could work as a base material in principle.

ChemPlusChem, DOI: 10.1002/cplu.201600021