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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.



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RE: Great!
By LivingDedBoy on 6/11/2008 12:50:44 PM , Rating: 2
Ahh but they do emit EMF, meaning it will increase the risk of cancer, regardless of how much energy it takes to effectively damage DNA.

Anything that puts out any kind of radiation can increase your risk. Even if it is .000000001% its still an increase over someone who does not expose themselves to said radiation.

I'm just saying that everything can increase your risk of cancer. If you take the time to look around and do some research I'm sure you can find some study or another that relates any givin thing to increasing the risk of cancer. All in all I could really give less of a crap if these can increase the risk, so could anything else for that matter.

If these carbon nanotubes can filter out any givin chemical from water, meaning less disease in general, more usable materials etc. I'm not gonna cry about an increased risk of cancer since there is already so much out there that can do the same.


"There is a single light of science, and to brighten it anywhere is to brighten it everywhere." -- Isaac Asimov











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