Week 8/Nanotechnology E.C. Lecture/Lam Tran

Feb 24 2009: SNNI-Safer Nano materials and Nano Manufacturing initiative

I went to the special lecture on greener nanotechnology. Nano technology is complex. Making something that is only a few nanometers long and wide produces wastes that are 6000 to 15000x more wastes than product. The actual volume of wastes maybe small at the frontier of nano technology but once these processes are scaled up to the industrial level for commercial use, these numbers can become staggering.There are other risks involved with nano tech such as the effects of the chemicals and materials on its toxicity, if it is weathered down in the environment or transformed into other compounds, and how it is moved throughout the environment or does it simply settle and deposit somewhere. The complexity of these issues make it very hard to thoroughly assess the risk factor. Risk is defined by the exposure times the hazard. The greater the chance of exposure, the greater the risk. Same goes if the hazard of the material is high. In his words, there will always be a chance of exposure so the real focus is to bring down the hazard factor. This way the overall risk of nano tech will drop. This leads to the idea of Green Nano Tech

The guest speaker from Oregon University brought up two examples that illustrated their work on making Nano Tech more safe.

The materials used to create the nanoparticles are sometimes very dangerous. An example is the B2H6 (Tolumine i believe was what it is called) compound in creating the Au-TPP particle. The overall process is something like this:

HAuCl4+PPh3 into ethanol yields AuCl(PPh3)

AuCl(PPh3)into B2H6+C6H6= Gold nanoparticle Au-TPP

The B2H6 solvent is considered flammable and toxic and was able to be replaced by a different chemical that was easier to control and dispose of. It also increased the speed of the reaction. The message behind this example is the need for increased research on current nanoparticles and their manufacturing process.

The second example was about how normally nano particles are synthesized. There is a solution and another solution is poured into it. Normally the color changes to a different color. The one that was particularly used in the example had a very fast reaction time (only a few seconds) but a very low yield (~21%). What they found out was that a simple T mixer could greatly improve the synthesis. My manipulating the length of the tubes at the end of the mixer, you can separate the different compounds. This can very easily seperate the yield from the wastes. By doing so with just tubes, the process now is much faster and requires much less energy.

It was a very technical lecture with a lot of info thrown at you all at once. You would probably need a fairly strong background in chemistry to keep up with the pace. However, it was quite interesting to see what some of the things people are working on at the frontier of science.

Lam Tran

notes that i took while i was there:

Nanotechnology implications: complexity-> Toxicity, Environmental transport, Weathering/transformation, Characterization, data monitoring.

balance between risks and benefits; is it worth it?

Greener nanotech:

Focus on Hazards rather than the exposure because the release is inevitable.

use of safer chemicals and use less hazardous chemical synthesis

prevent wastes

example: HAuCl4+PPh3->ethanol->AuCl(PPh3)->B2H6+C6H6= Gold nanoparticle Au-TPP

the B2H6 is very hazardous and dangerous to environment and was replaced with something much more safe.

atom economy

design for degradation/end of life: life cycle of the material from manufactoring to end.

use of inter disciplinary teams

chemists, physicists, toxicologists, engineers, biologists

Nanoscale characterization: Lorry Lokey Labs

30 mil worth of shared equipment, so great that other companies wish to use these Labs in Oregon (Sony)

Super quiet, lab is anchored straight on the bedrock

Easy to mix but hard to separate: Improved purification of functional nanoparticles. Traditional solvents to diafiltration which does not require any organic solvents and can be done in 15 minutes rather than 3days with solvents. Also produces the best pure results.

Use of simple T mixer can help seperate materials of low synthesizing yield with wastes by simply manipulating the length of the tubing which can help lower wastes and energy demand of manufacturing.

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