backtop


Print 27 comment(s) - last by Jedi2155.. on Jun 15 at 8:35 AM

New nanotech-based filtration could save buckets of energy.

Seawater desalination is no easy task. Traditionally, vacuum distillation techniques have been used, and this process requires a great deal of energy. More recently, reverse osmosis facilities have come online. These facilities use a special permeable membrane to separate salts and minerals from liquid water. As of January, there are more than 13,000 desalination plants pumping out over 12 billion gallons of water a day.

While cogeneration facilities have helped to cut down the cost of vacuum distillation and reverse osmosis plants are marginally more efficient in terms of energy used, work in the unrelated field of biology and molecular transport systems may promise an even better type of filtering membrane for osmosis systems.

Researchers at the Lawrence Livermore National Laboratory, while studying the process of molecular transportation across cell membranes, have come up with a new type of filter. The filter mimics the properties of cell membranes and is especially efficient in the transport and filtration of water molecules. Their work is based on -- you guessed it -- carbon nanotubes.

What makes these CNT-based filters so efficient is their hydrophobic properties, or the way they repel water molecules. Water moves through the CNT channels in a membrane much more quickly than in conventional filters because the molecules do not stick to the sides of CNTs. Instead, they stream through them unhindered, like a bullet train.

After this discovery, the researchers tested their artificial membrane for desalination efficiency. They found that the 1.6nm diameter tubes successfully prevented the ions that make up salts from traversing while letting the water molecules flow freely. The mechanism for this selectiveness lies in the small diameter of the channel along with the charge held at the end of the nanotubes.

Aleksander Noy, a senior member of the LLNL research team explains, “while carbon nanotube membranes can achieve similar rejection as membranes with similarly sized pores, they will provide considerably higher permeability, which makes them potentially much more efficient than the current generation of membranes.”

While the LLNL findings promise a great deal for desalination and other processes where similar filtering is used, some refinement will still be required. The ability to construct membranes of different materials and control the charge and diameter of the nanotube pores will weigh heavily into their efficiency and usefulness in different applications.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: Great!
By Jedi2155 on 6/15/2008 8:35:43 AM , Rating: 2
I also have another article in a IEEE spectrum magazine laying around that studies the effects of ionizing radiation emitted from mobile devices such as cell phones etc. to be of such insignificant value relative to the many other things we encounter in life. It is pretty insignificant and I feel safe around most forms of EM radiation. Although a EM Pulse to level a nuke would form still scares me :).


"You can bet that Sony built a long-term business plan about being successful in Japan and that business plan is crumbling." -- Peter Moore, 24 hours before his Microsoft resignation











botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki