Apr 1, 2004
Motion of nanomaterials in water depends on type
Broad statements about the environmental risks of nanomaterials may not be particularly meaningful. That’s the conclusion of researchers at Rice University, US, who looked at the movement of different nanomaterials in aqueous systems.
“This is the first work to look at the movement of nanomaterials in a water environment,” Mark Wiesner of Rice University told nanotechweb.org. “[We found that] not all nanomaterials are mobile. The movement of nanomaterials in the environment is very case-specific.”
Wiesner and colleague Helene Lecoanet tested the mobilities of three fullerenes under pH and ionic strength conditions similar to those in many groundwater aquifers. They compared these mobilities with those of four oxide nanomaterials and found that the particles exhibited “widely differing transport behaviours”.
“While the transport of mineral nanoparticles is well described by current models for particle transport in porous media such as ground waters, the transport of fullerenes cannot be described by these models and shows some unusual properties,” said Wiesner. “The form of buckyballs that has received the most attention in recent toxicity studies is the least mobile form of fullerenes that we have tested, thus the potential for environmental risk should be somewhat reduced.”
Wiesner believes his work will help scientists to understand the potential efficiency of using nanoparticles to clean up groundwater pollution, as well as aiding the assessment of any environmental risks that nanomaterials might present. Now, the Rice team is investigating the transport mechanisms that appear to be unique to fullerenes. They are examining the effect on nanoparticle transport of naturally occurring materials in water, and expanding the range of nanomaterials under scrutiny to include particles with catalytic applications, such as those proposed for groundwater clean-up.
The scientists reported their results at the American Chemical Society meeting held in Anaheim, US, this week.
About the author
Liz Kalaugher is editor of nanotechweb.org.