Carbon nanotube membranes made from plastic bags

A process for turning waste plastic bags into a high-tech nanomaterial has been developed by researchers at the University of Adelaide.

The nanotechnology is derived from non-biodegradable plastic shopping bags to make carbon nanotube membranes, which have a variety of potential advanced applications including filtration, sensing, energy storage and a range of biomedical innovations.

‘Non-biodegradable plastic bags are a serious menace to natural ecosystems and present a problem in terms of disposal,’ said Prof Dusan Losic, ARC Future Fellow and Research Professor of Nanotechnology in the University’s School of Chemical Engineering.

‘Transforming these waste materials through ‘nanotechnological recycling’ provides a potential solution for minimising environmental pollution at the same time as producing high-added value products.’

Carbon nanotubes are 1nm diameter cylinders of carbon atoms and are the strongest and stiffest materials yet discovered. Their unique mechanical, electrical, thermal and transport properties present exciting opportunities for research and development and they are already used in industries including in electronics, sports equipment, long-lasting batteries, sensing devices and wind turbines.

The University of Adelaide’s Nanotech Research Group has grown the carbon nanotubes onto nanoporous alumina membranes. They used pieces of grocery plastic bags which were vaporised in a furnace to produce carbon layers that line the pores in the membrane to make the carbon nanotubes.

The idea was conceived and carried out by PhD student Tariq Altalhi.

‘Initially we used ethanol to produce the carbon nanotubes,’ Prof Losic said in a statement. ‘But my student had the idea that any carbon source should be useable.’

The potential market for carbon nanotubes is said to hinge on industry’s ability to produce large quantities more cheaply and uniformly. Current synthesis methods usually involve complex processes and equipment, and most companies on the market measure production output in only several grams per day.

‘In our laboratory, we’ve developed a new and simplified method of fabrication with controllable dimensions and shapes, and using a waste product as the carbon source,’ said Prof Losic.

The process is also catalyst and solvent free, which means the plastic waste can be used without generating poisonous compounds.

This research has been published online ahead of print in the journal Carbon.