Study shows carbon nanotubes may pollute water
Resembling human hair at 7220x magnification, these are actually carbon nanotube bundles. (Matt Brown)
An environmental engineer has shown that carbon nanotubes have the potential to pollute natural waterways.
These tiny, hollow tubes – only a few atoms across – are extremely strong and flexible. They have applications in manufacturing, from everyday items like sports gear to a futurist–sounding elevator to space. Until recently, scientists believed that nanotubes clump together in water and settle on the bottom.
That was before Jaehong Kim of the Georgia Institute of Technology immersed multiwalled carbon nanotubes in water from Georgia’s Suwannee River. Residue from soil and leaves had a surprising effect on the nanotubes.
Jaehong Kim: In the presence of this organic matter they get stabilized, meaning that they are suspended in the water for a long time, raising potentially a concern as a water pollutant.
Carbon nanotubes aren’t yet in wide circulation. They don’t yet pose a threat to rivers and oceans. But, Kim said, now is the time to pay attention.
Kim: Our past approach was making all these chemicals and pollute the environment and worry about the remediation. Instead, with nanotech we do have some opportunities, meaning that we can now start to look into their environmental implication.
With thanks today to the National Science Foundation, we’re Block and Byrd for Earth & Sky.
Jaehong Kim also said, “This is exploratory research. I’m not raising any warning sign at this stage. I’m not saying there is a potential a possibility that you’ll find carbon nanotubes in the river at this moment. We’re trying to understand the environmental impact, at the same time as its development and applications. We don’t want to make the mistake we’ve made with many other chemicals we’ve used in the past. Our past approach was to make these chemicals and pollute the environment and worry later about the remediation. With nanotech, we do have some opportunities. We can now start to look into their environmental implication at the same time as their development.”
He added, “These carbon nanotubes are extremely hydrophobic. They don’t like to be dispersed in water. So when they apply in the water system, they use encapsulating agents such as surfactant like soap or polymers in order to wrap this hydrophobic surface, so probably in the similar mechanism what this natural organic matter is doing is wrapping the surface of the nanotubes such that now it is not hydrophobic anymore but now they are dispersed, suspended in water as stable colloids.”
Our thanks to:
Jaehong Kim
Georgia Institute of Technology
If ‘Silent Spring’ taught us anything, it is that any thoughtful human should raise the alarm at the release of any unknown/uncontroled release. Do you (anyone?) know what kinds of release have occurred already?
As I understand, we know virtually nothing about the behavior of carbon fibers, much less carbon tubules in nature/living systems.
The grammer & syntax of your long last sentance needs some editing to make better sense.
jrb, I agree. It’s unsettling to imagine carbon nanotubes released in rivers and streams, when in fact we know very little about how they’ll interact with a natural ecosystem.
But I also should say that the scientists who are working in nanotech seem very much aware of the need for caution.
To me, hearing them talk, they seem to be doing a pretty good job of raising the right questions. Many seem to be making a real effort to get some of the answers now, before carbon nanotubes and other nano products are in wide circulation. This study by Jaehong Kim is one example of that effort.
We’ve got lots more about nanotechnology, if you’re interested.
This article on the top 10 things to know about nanotech might be a place to start.
Hi all,
As a nanotechnologist with training in environmental engineering, I have to agree with Deborah that the nanotechnology community as a whole is being much more environmenatlly responsible than other emerging technological communities have in the past. I have heard of Kim before, but have not yet had the opportunity to look into any of his work. I will have to do that. Considering the nature of Kim’s research, I wouldn’t say we know nothing about these particles’ behavior in nature anymore. I find it heartening that someone is actually looking into what the environmental impact of nanotubes, as well as other forms of nanotechnology, might be before we create a new problem. What he said about the organic matter creating a hydrophillic coating on the otherwise hydrophobic nanotubes makes complete sense. Our company’s research consists of taking hydrophobic nanocrystals and finding ways to make them hydrophillic so that they can be used as biomarkers, and then to subsequently improve the resulting products. What great research! It would be so interesting and challenging to figure out the exact mechanism by which this occurs in the natural environment. I will definately have to check out this research. Thanks for bringing this to my attention!!!