Boron-nitride nanotubes speed desalination, says Australian research
25 Aug 09 by desalination
Researchers from The Australian National University (ANU) claim to have discovered a way to speed the desalination of seawater by up to five times using nanotubes made from boron and nitrogen atoms.
In a paper published in the journal Small, researchers Dr Tamsyn Hilder, Dr Dan Gordon and group leader Professor Shin-Ho Chung from the Computational Biophysics Group at the Research School of Biology at ANU say that boron-nitride nanotubes have shown superior water flow properties compared with carbon nanotubes, and are thus expected to provide a more efficient water purification device.
“Using boron nitride nanotubes, and the same operating pressure as current desalination methods, we can achieve 100% salt rejection for concentrations twice that of seawater with water flowing four times faster, which means a much faster and more efficient desalination process,” says Dr Hilder.
Hilder, Gordon and Chung use computational tools to simulate the water and salt moving through the nanotube. They found that the boron nitride nanotubes not only eliminate salt but also allow water to flow through extraordinarily fast, comparable to biological water channels naturally found in the body.
“Our research also suggests the possibility of engineering simple nanotubes that mimic some of the functions of complex biological nanotubes or nanochannels,” said Professor Chung, and work is continuing to investigate these possibilities further. These devices, once successfully manufactured, may be used for antibiotics, ultra-sensitive detectors or anti-cancer drugs
Using molecular dynamics simulations, the paper shows that a (5, 5) boron-nitride nanotube embedded in a silicon-nitride membrane can, in principle, obtain 100% salt rejection at high concentrations owing to a high energy barrier, while still allowing water molecules to flow at a rate as high as 10.7 water molecules per nanosecond (or 0.9268 L/m² h).
Furthermore, ions continue to be rejected under the influence of high hydrostatic pressures up to 612 MPa. When the nanotube radius is increased to 4.14 Å, the tube becomes cation-selective, and at 5.52 Å, the tube becomes anion-selective.
On the health dangers of nanotubes, Dr Hilder told D&WR, “Our research investigates the use of nanotubes made from boron nitride nanotubes, which a have improved biocompatibility as compared to carbon nanotubes. Recent studies have shown that boron nitride nanotubes are non-cytotoxic.”
Login on register to comment
A world leader committed to preserving resources through desalination and reuse
The Group designs
Leading expert delivers online masterclass on membrane fouling
There is only one week left to register for this exciting new format of online event and deepen your understanding of membrane fouling in only one hour.
Singapore International Water Week Turns 10 Years: Celebrating a Decade of Accomplishment in the Global Water Industry
The Singapore International Water Week (SIWW) is the world's premier platform to connect the water industry for innovative solutions and sustainable urban water management. The biennial event gathers stakeholders from the global water industry to share best practices
Related supplier content
Xylem reuse system to up potable water supply in Los Angeles
Water technology company
Sterlitech offers new ultrafiltration membranes
Laboratory products and membrane testing firm Sterlitech is offering Synder Filtration's recently developed ultrafiltration membranes
Osmoflo reports concentrate reduction success
Australian desalination company Osmoflo has reported success with site tests of its concentrate reduction technology for reverse osmosis (RO) plants. The firm said its Brine Squeezer system increased recovery from 80% to 95% in a mine wastewater recovery pilot.