Sandia Labs Research Uncovers Better Water Purifying Compound

By using gallium, researchers say they have come up with a compound that could do a better job of removing contaminants in untreated water than commercial products.

Ucilia Wang July 24, 2009

Ucilia Wang

It took just one atom, and that made all the difference.

Researchers at the Sandia National Laboratories have devised a more effective compound for purifying water by replacing an aluminum atom with the gallium atom in an aluminum oxide cluster, which already is used as a decontaminant.

The result was a reagent, also called a coagulant, that does a better job of binding bacteria, virus and other yucky materials in untreated water than those found in commercial products today, said May Nyman, lead researcher of the project.

Sandia said it's now working with an undisclosed chemical company to figure out if the new compound could make a good commercial product for wastewater treatment plants or facilities for making river water potable.

Water isn't an infinite resource, and a growing global population has raised a chorus of concerns about securing ample supply of water and making it potable. Already, more than a billion people in the world don't have access to clean drinking water, according to a United Nations report.

Venture capitalists often cite water as a critical area of investment (see Investors High on Water and A Guide to the Water World).

"Human consumption of 'challenged' water is increasing worldwide as preferred supplies become more scarce," Nyman said in a statement. "Technological advances like this may help solve problems faced by water treatment facilities in both developed and developing countries."

Her work was published last month in Environmental Science & Technology, a journal by the American Chemical Society (see abstract). Nyman worked with Tom Stewart, a microbiologist at Sandia, on the project.

The research looked for ways to improve the ability of the aluminum oxide cluster to attract and trap contaminants. The researchers used not only gallium but also germanium as a substitute to see how each performs. The key, it turned out, was to find the material that could improve a coagulant's electrostatic charge more reliably.

To carry out the substitution, Nyman said she first dissolved aluminum salts in the water and heating it. She then separately put gallium salts into a sodium hydroxide solution. The sodium hydroxide solution is then added to the aluminum mixture.