Carbon Nanoparticle Could Keep the Flow Going

Author:  Schwartzman Nina
Date:  April 2009

One of the biggest costs involved in treating water is cleaning the filters that purify the water. Microbes in the water agglomerate on the surface of the filters in a process called biofouling. This clogs the filters, requiring costly cleaning. New research at Duke University could help prevent this clogging through the use of a carbon nanoparticle called the "buckyball."

The results of the study, published in the Journal of Membrane Science, showed that when filters are coated with buckyballs, far fewer microbial colonies attach themselves to the filters. Coating of filters and pipes with this material could significantly reduce biofouling, thus lowering the cost of water treatment.

The buckyball, a 60-carbon molecule in the shape of a geodesic dome, is part of a group of carbon nanoparticles called fullerenes, which also includes carbon nanotubes. Buckyballs are named after Buckminster Fuller, the father of the geodesic dome.

Claudia Gunsch, the senior researcher on the project, said that the mechanism behind the microbial inhibition is not certain. Buckyballs were found to increase the membranes' hydrophobicity, or the tendency to repel water. Gunsch suggested that the hydrophobicity probably contributes to the anti-biofouling effect, but that buckyballs may also have a toxic effect on the microbes. So-Ryong Chae, a post-doctoral fellow who worked on this project, reported that the molecule suppressed the microbes' respiration, or the process by which they make energy.

"As the concentration of buckyballs increased," said Chae, "so did the inhibition of respiration."

According to Gunsch, there is currently no low-cost solution to biofouling. Filters are washed using high pressure water to get through their small pores, or they are simply replaced.

"These membranes have very small pores, so they can get stopped up quickly," she reported. "If we could increase the time between membrane replacements by 50 percent, for example, that would be a huge cost savings."

Gunsch said that as fullerenes become more prevalent and affordable, they may become a cost-effective way to prevent biofouling. In addition to coating filters, she foresees their use in coating pipes, since they also become clogged with microbial films.

However, she warned, the environmental impact of these particles must be determined before they can be used in water treatment facilities. The new Center for Environmental Implications of Nanotechnology at Duke will be investigating the environmental impact of fullerenes, as well as other nanoparticles.

Written By: Nina Schwartzman

Edited by: News and Features Editor Brittany Raffa and Professional Reviewer Renee Gilberti

Published by Falishia Sloan