Carbon nanotubes (CNTs) are an important new class of engineered nanoparticles. CNTs are pure carbon macromolecules, which are cylindrical in shape, with diameters in the nanometer range and lengths up to several tens of micrometers. CNTs consist of graphene sheets rolled up to form seamless cylinders and may be single-walled or multi-walled. The unique combination of physical and chemical properties attributed to CNTs is promising for many practical applications. Because of the forecasted increase in manufacture and the multiple uses of CNTs, it is likely that CNTs will be released into the environment. Fate and effect of CNTs depend on their aggregation state in natural waters. CNTs are virtually insoluble in water and do not form stable suspensions. However, they can be solubilized by addition of polymers such as proteins, detergents and polysaccharides. Natural polymers present in natural waters (e.g. humic and fulvic acids) may be able to solubilize CNTs. The aim of this project is to analyze the behavior of CNTs in natural waters under environmental conditions. In this context, it will be investigated if

• biopolymers
• biosurfactants
• anthropogenic detergents

at environmentally relevant concentrations have a solubilizing effect on CNTs.

In collaboration with Bernd Nowack (Empa), Laura Sigg and Ralf Kägi (Eawag)

Contact: Irène Schwyzer