Can buckyballs reduce desalination membrane biofouling?
The giant carbon molecule buckminsterfullerine (C60) or "buckyballs" has been found in research to hinder biofouling on membranes such as those used for desalination.Research engineers at Duke University in the US state of North Carolina have found that buckyballs may be able to keep water membranes and pipes clear of bacteria and micro-organism build-up.
In a release issued on 5 March 2009, So-Ryong Chae, post-doctoral fellow in Duke's environmental and civil engineering department, said that the addition of buckyballs to treatment membranes had a two-fold effect.
First, treated membranes showed less bacterial attachment than non-treated membranes. After three days, the membranes treated with buckyballs had on average 20 colony forming units, the method by which bacterial colonies are counted.
"In contrast, the number of bacterial colonies on the untreated membrane was too numerous to count," Chae said.
Chae also found that the presence of the buckyballs inhibited respiration, or the ability of the bacteria to use oxygen to fuel its activities.
"As the concentration of buckyballs increased, so did the inhibition of respiration," Chae said. "This respiratory inhibition and anti-attachment suggests that this nanoparticle may be useful as an anti-fouling agent to prevent the biofouling of membranes or other surfaces."
Claudia Gunsch, assistant professor of civil engineering at Duke's Pratt School of Engineering, said the mechanisms involved are not well-understood.
Both Gunsch and Chae believe that since buckyballs are one of the most widely used nanoparticles, additional research is needed to determine if they have any detrimental effects on the environment or to humans. This is one of many issues being studied at Duke's Center for Environmental Implications of Nanotechnology.
"We need to figure out how resistant these coatings will be to long-term use," Gunsch said. "If they can indeed prevent fouling, they will last longer. If they slough off over time, we need to know what the effects will be."
The current experiments in the laboratory were conducted with Escherichia coli K12, a strain of the bacterium that is widely used in laboratory experiments.
"We focused on a quite specific microorganism, so the next stage of our research will to see if these nanoparticles will have the same effects on bacteria commonly found in the environment or those in mixed microbial communities," Chae said. "We also plan to build a small-scale version of a treatment plant in the lab to conduct these tests."
The football-shaped buckyballs molecule was named after the geodesic dome architect R Buckminster Fuller, whose buildings have a similar hexagonal panel structure.
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