August 24, 2009
Australian scientists have discovered a new way of removing salt from seawater that's cheaper, faster and more efficient than current desalination methods.
They believe tiny nanotubes, made of boron and nitrogen atoms and 10,000 times smaller than a single strand of human hair, could one day help solve the world's water crisis.
Scientists from the Australian National University found the nanotubes, which would replace current salt filters, use less energy to process more water, more quickly.
And because they also eliminate salt, rather than just extracting it, it cuts down another costly step in the desalination process.
The discovery has the potential to transform the way countries approach desalination, researcher Tamsyn Hilder said.
"The (Australian) government is already driving towards (desalination), but I think this will make it a much more economically viable option," she told AAP.
At maximum efficiency, the nanotubes would be capable of processing water up to five times faster than normal methods, while reducing running costs by up to 75 per cent.
It could also potentially decrease construction costs for desalination plants, which presently run up into the billions of dollars, Dr Hilder said.
"When you think about the world 97 per cent of the world is seawater, two per cent is ice, and one per cent is freshwater.
"That's an incredibly large amount of water that we're not tapping into."
Desalination plants currently push huge volumes of water through polymer-type filters, which trap salt on one side.
The salt is then routinely removed to allow the water to run through at speed.
"Using boron nitride nanotubes, and the same operating pressure as current desalination methods, we can achieve 100 per cent salt rejection for concentrations twice that of seawater with water flowing four times faster," Dr Hilder said.
"(It) means a much faster and more efficient desalination process."
The nanotubes mimicked biological water channels found in the human body.
The year-long study has been published in the journal, Small.