Topic: Nanotubes could change face of filters

[Nemesis]

Link to full article

They have been working for several years with nanotubes -- sheets of highly specialized, man-made carbon atoms that have been rolled into tiny tubes more than 10,000 times thinner than a human hair. The group reported two years ago that it had learned how to combine billions of the tubes to form membranes that could serve as highly efficient filters.

Now, they have found that fluids can pass through those nanotube membranes at very high rates of speed. The rapid-flow effect had been theorized, but the UK group is the first to confirm it, Hinds said.

Link to 2nd full article

To test their cylinder as a filter, the researchers capped one end and let petroleum flow into it. As the oil passed through the cylinder's wall, the membrane caught the large and complex hydrocarbons--a necessary step in making gasoline.

In a second experiment, Ajayan and his colleagues tested their filter on contaminated water. The researchers had added Escherichia coli, the bacterium responsible for a common intestinal disease, to a sample of water and passed the sample through the filter. Analysis of the filtered water showed that it was devoid of E. coli. More surprising, when the researchers tried water contaminated with the poliovirus, which is much smaller, not one virus made it through the sieve.

The ideal filtration system?

[Stormbringer]

Asimilar article on this technology has it as the means to finally bring the hydrogen economy into reality in terms of fuel cell production.

[Nemesis]

I haven't seen an article like that - yet.  But it wouldn't surprise me.  In some ways carbon nanotubes are for the 21^st century as the sulfa drugs were to the early 20^th century medicine - a miracle that can do anything.  As such I do take much of it with a grain of salt.  The filtration feature does sound interesting and likely. 

A nanotubes diameter is small enough to block all but the smallest molecules from passing through.  Making a sheet that passes water but not larger molecules (like petroleum) for cleaning up oil spills.  Water filtration for military, sports and home use could be revolutionary.  Medical masks that don't pass viruses or bacteria but do passs air etc.

[Stormbringer]

Sorry it was not carbon nano tubes

http://nanotechwire.com/news.asp?nid=1765

Nanotechnology could promote hydrogen economy
 
Say “nanotechnology” and people are likely to think of micro machines or zippy computer chips. But in a new twist, Rutgers scientists are using nanotechnology in chemical reactions that could provide hydrogen for tomorrow’s fuel-cell powered clean energy vehicles.

In a paper to be published April 20 in the Journal of the American Chemical Society, researchers at Rutgers, The State University of New Jersey, describe how they make a finely textured surface of the metal iridium that can be used to extract hydrogen from ammonia, then captured and fed to a fuel cell. The metal’s unique surface consists of millions of pyramids with facets as tiny as five nanometers (five billionths of a meter) across, onto which ammonia molecules can nestle like matching puzzle pieces. This sets up the molecules to undergo complete and efficient decomposition.

“The nanostructured surfaces we’re examining are model catalysts,” said Ted Madey, State of New Jersey professor of surface science in the physics department at Rutgers. “They also have the potential to catalyze chemical reactions for the chemical and pharmaceutical industries.”

A major obstacle to establishing the “hydrogen economy” is the safe and cost-effective storage and transport of hydrogen fuel. The newly discovered process could contribute to the solution of this problem. Handling hydrogen in its native form, as a light and highly flammable gas, poses daunting engineering challenges and would require building a new fuel distribution infrastructure from scratch.

By using established processes to bind hydrogen with atmospheric nitrogen into ammonia molecules (which are simply one atom of nitrogen and three atoms of hydrogen), the resulting liquid could be handled much like today’s gasoline and diesel fuel. Then using nanostructured catalysts based on the one being developed at Rutgers, pure hydrogen could be extracted under the vehicle’s hood on demand, as needed by the fuel cell, and the remaining nitrogen harmlessly released back into the atmosphere. The carbon-free nature of ammonia would also make the fuel cell catalyst less susceptible to deactivation.

When developing industrial catalysts, scientists and engineers have traditionally focused on how fast they could drive a chemical reaction. In such situations, however, catalysts often drive more than one reaction, yielding unwanted byproducts that have to be separated out. Also, traditional catalysts sometimes lose strength in the reaction process. Madey says that these problems could be minimized by tailoring nanostructured metal surfaces on supported industrial catalysts, making new forms of catalysts that are more robust and selective.

In the journal article, Madey and postdoctoral research fellow Wenhua Chen and physics graduate student Ivan Ermanoski describe how a flat surface of iridium heated in the presence of oxygen changes its shape to make uniform arrays of nanosized pyramids. The structures arise when atomic forces from the adjacent oxygen atoms pull metal atoms into a more tightly ordered crystalline state at temperatures above 300 degrees Celsius (or approximately 600 degrees Fahrenheit). Different annealing temperatures create different sized facets, which affect how well the iridium catalyzes ammonia decomposition. The researchers are performing additional studies to characterize the process more completely.

The Rutgers researchers are conducting their work in the university’s Laboratory for Surface Modification, which provides a focus for research into atomic-level phenomena that occur on the surface of solids. It involves the overlapping disciplines of physics, chemistry, materials science and engineering. Their work is supported in part by grants from the U. S. Department of Energy’s Office of Basic Energy Sciences.

http://pubs.acs.org/cgi-bin/asap.cgi/jacsat/asap/html/ja042617c.html

[NJAntman]

Whoa! Some of my state tax dollars are actually funding something to make the future brighter!

Hey, are those pigs flying outside my window?!

[Nemesis]

Sorry it was not carbon nano tubes

Nanotech like nanotubes has the "miracle drug" psychology.  Of course nanotubes are an aspect of nanotech but gets treated differently since the tubes themselves are mostly wanted in macroscopic lengths and bundles.

Anything that gives better ways to store/transport/generate hydrogen is of interest.  I do suspect an "alcohol" (non drinkable versions) economy before a hydrogen one.  Alcohol is just too much easier to generate, store, transport and use at our current technology level and for at least the near future.  It can also be used in fuel cells.

Another alternative would be methane.  A gas but easily handled with current tech.  Bad press as a greenhouse gas but it does break down fairly quickly.

There are so many potential revolutions to technology on the brink right now that the next 20 years could be amazing if even a few of them break through into practical products.  I do fear that the current patent climate will cause many delays though.