Buckyballs in the Water

June 1, 2009

Illustration of a buckyball © Michael Freeman/MedNet/Corbis

Spherical carbon molecules known as buckyballs may be able to keep the nation's water pipes clear in the same way clot-busting drugs prevent arteries from clogging up.

Engineers at Duke have found that buckyballs hinder the ability of bacteria and other microorganisms to accumulate on the membranes used to filter water in treatment plants. They think that coating pipes and membranes with these nanoparticles may prove to be an effective strategy for addressing one of the major problems—and costs—of treating water.

"Just as plaque can build up inside arteries and reduce the flow of blood, bacteria and other microorganisms can over time attach and accumulate on water-treatment membranes and along water pipes," says So-Ryong Chae, postdoctoral fellow in Duke's civil and environmental engineering department. The results of his experiments, conducted under the aegis of the Center for Environmental Implications of Nanotechnology (CEINT), were published in the Journal of Membrane Sciences.

As bacteria accrete on water-treatment equipment surfaces, they attract other kinds of organic matter and can clog pipes, a process known as biofouling. Currently, the only options to clear these blockages, according to Chae, are to dig up pipes or replace the filtration membranes, both of which are expensive and inconvenient.

A buckyball, or C60, is one shape within the family of tiny carbon shapes known as fullerenes. It consists of 60 carbon atoms arranged in a shape very much like a soccer ball. The molecules, which resemble a geodesic dome, are named after its inventor, Buckminster Fuller.

The addition of buckyballs to the treatment membranes had a two-fold effect: preventing bacterial buildup and inhibiting respiration, or the use of oxygen to fuel bacteria life processes. In the experiment, membranes treated with buckyballs had an average of twenty bacterial colony units in contrast to the number on untreated membranes, which were too numerous to count.

While results look promising, further research will be needed to determine the environmental and public-health impact of using buckyballs in water systems. CEINT, a multi-university collaboration founded last year and based at Duke, will now look into these potential ill effects.

The current laboratory experiments were conducted with Escherichia coli K12, a widely studied strain of bacteria. The next stage of research will determine whether buckyballs will have the same effects on bacteria more commonly found in mixed-microbial communities like those in water-treatment systems.