Carbon nanotubes are just the thing for cleaning up poisonous pollutants, new research has found. These tiny tubes of pure carbon mop up dioxins, the hazardous and persistent by-products of a wide range of industrial processes that contaminate the air, soil, water and, thence, the food chain. Most countries now impose emission limits on sources that generate dioxins, but they continue to pose an environmental hazard. Richard Long and Ralph Yang of the University of Michigan have found that carbon nanotubes attract much more dioxin than the graphite-like substance, activated carbon, currently used to clean up incinerator gases 1 .
Graphite consists of flat sheets of interlinked carbon atoms.
In nanotubes, these sheets are rolled into cylinders only a few millionths of a millimetre wide. Because tubes are hollow, gases can pass through as well as between them. So a mass of carbon nanotubes is rather like porous graphite. To put these promising findings into industrial practice, however, needs a cheap source of carbon nanotubes. Carbon Nanotechnologies, the Houston company set up by chemistry Nobel prizewinner Richard Smalley, is making this one of their priorities.