Nano Coatings Stem Water-Pipe Clogs

Researchers at Duke University have come to respect the power of nano-engineered buckyballs.

In one project, the engineers found that ultrafine mesh coatings made of carbon buckyballs can hinder the ability of bacteria and other microorganisms to colonize the membranes that filter impurities from water. This is one of the major problems – and costs – in treating H2O.

The bacteria builds up and attracts other organic matter. In time, a film of biological material accumulates. A reduction in membrane-replacement cost, even of 50 percent, would translate to huge savings.

“Biofouling is viewed as one of the biggest costs associated with membrane-based water-treatment systems,” said Claudia Gunsch, assistant professor of civil engineering at Duke’s Pratt School of Engineering and senior member of the research team.

A buckyball is one shape within the family of nano-carbon shapes known as fullerenes. They’re both named after Richard Buckminster Fuller, the inventor of the geodesic dome, because their shapes resemble his famous structure.

When water-filtering membranes are treated with buckyballs, the researchers discovered that only a very small number of bacteria (20 units) are able to colonize on the surface material.

The Duke researchers plan to study other species of bacteria that would be encountered in the same kind of water treatment environments. And they plan to scale their system to simulate application in a full-scale treatment plant.

“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,” said So-Ryong Chae, post-doctoral fellow in Duke’s environmental and civil engineering department in a release. Experimental results were published March 5, 2009 in the Journal of Membrane Sciences.

In a separate research effort, scientists at the University of Leeds are working on a way to use bacteria to help clean foul water.

Harmful chromium compounds are commonly found in groundwater at sites receiving waste from former textile factories, smelters and tanneries. This wastewater has been linked to cancer.

Dr. Doug Stewart heads the research team from the school of civil engineering and has discovered that adding dilute acetic acid (vinegar) can stimulate bacteria strains capable of converting chromium into a harmless substance.

Researchers plan to further study the bacteria and conditions under which it can operate. This environmentally sensitive approach to cleanup should be welcome. But we’ll have to wait a few years to see if these systems become widespread. –Lee Bruno

Categorized | Engineering, Microorganisms, Other
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