Nanotechnology worth its salt

22 August 2006

Researchers at Flinders University have received funding of AUD$735,000 from the Australian Research Council to investigate using nanotechnology for the desalination of seawater.

Existing methods of desalination remove salts from water by reverse osmosis, a process in which water is passed through a porous membrane. The use of currently available materials, however, requires considerable pressure to be applied to push the water through the membrane.

The costs in terms of energy make this form of reverse osmosis filtration expensive, and it is generally only employed in affluent countries with scant fresh water resources.

If the permeability of the membrane can be improved while still filtering out the saline ions effectively, less pressure and therefore less energy will be needed, reducing energy costs drastically.

One potential approach would use a matrix of carbon nanotubes encased in a polymer matrix to construct a membrane, relying on the diameter of the nanotubes to allow water through but filter out salts.

The alternative approach would see the nanotechnologists construct their own chemical nanotubes from the molecules of fatty acids.

Once a membrane is found to be viable, it can be incorporated into a filter unit, and the effectiveness of its filtration will be compared with current commercial systems. The researchers anticipate that the new filters would require less energy and could be powered using sustainable energy.