Carbon Nanotubes: Innovative Technology Or Risk To Health Or Environment?

– I’ve written before about my concerns on the nanotechnology they are gleefully rolling out into our environment.   :arrow:, :arrow:, ➡

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Carbon nanotubes have made a meteoric career in the past 15 years, even if their applications are still limited. Recent research results show that – apart from their favorable mechanical and electrical properties – they also have disadvantageous characteristics.

One aspect which has rarely been considered so far is now addressed by researchers of the research center Forschungszentrum Dresden-Rossendorf. “If the application of products and commodities containing carbon nanotubes will increase in the future, then there will be a higher probability for the tubes to get into the environment during their production, usage or disposal, to be distributed there, and to bind pollutants such as heavy metals on their way trough the environment”, says Harald Zaenker, scientist at the FZD.

Via water into the environment

An important way for carbon nanotubes of getting into the environment is the way via the water. In their original state, the flimsy carbon fibers with a diameter of less than 50 nanometers (1 nanometer = 1 millionth of a millimeter) are hardly water-soluble. At first glance, they should therefore not be mobile in groundwater, lakes etc., i.e. they should rapidly settle or deposit. However, carbon nanotubes are able to form colloidal solutions if their surface structure is changed. Changes in the surface structure can be brought about deliberately during the production of the tubes or can be induced by natural processes if the tubes are released into the environment.

A colloidal solution, unlike a true solution of water-soluble substances, is a solution in which the apparently dissolved substance is finely dispersed in the solvent forming tiny particles. These particles are still much bigger than the molecules of a dissolved substance in a true solution. As colloids, carbon nanotubes might be transported anywhere in environmental waters. It is known meanwhile that the tubes can even penetrate cell walls and, thus, might theoretically be able to enter also animal or human cells. In addition, changes in the surface structure of carbon nanotubes cause another effect: their capability to bind heavy metals is increased.


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