Air Date: Week of November 17, 2006

Nanoparticles of rust bind with arsenic in water. (Courtesy of Rice University Office of Media Relations and Information)

Scientists say rust, magnets and olive oil may be the solution to cleaning water with arsenic in developing nations. Ian Gray reports.

Transcript

GRAY: Mmmm, a big glass of water, fresh, clean…exactly the kind of water that most people in the world don't have.

But, a team of scientists at Rice University is developing a low-tech filter that could help remove at least one unwanted contaminant from drinking water. The prime ingredients? — iron rust, magnets and olive oil.

The widespread contaminant is arsenic, a natural metal in rocks and sediments that can leech into ground water. Conventional ways of getting rid of arsenic are expensive, but the scientists from Rice say they’ve found a way to do it for cheap.

To start with, the scientists combined rust with a fatty acid commonly found in olive oil, to produce a special nano-particle. They mixed small specks of rust into a liquid laced with arsenic. Arsenic naturally binds with other metals like iron, so the rust and arsenic stuck together. The scientists then planned to use a powerful magnet to pull the tiny particles out of solution, but what they found surprised them. The nano-rust particles amplified each other's magnetic interactions so a relatively weak magnet—say, a large refrigerator magnet—was able to do the job.

Since the nano particles are inexpensive to produce, the technology could be a boon for developing countries where arsenic is a big problem—countries like Bangladesh and Vietnam. The scientists hope they’ll be able to simplify the manufacturing process so that people in these countries can produce the nano-particles themselves. People could then use a low-tech filter and magnet to remove arsenic straight from their well water.

I’ll drink to that.

That this week’s note on Emerging Science, I’m Ian Gray.

 

Links

"Nanorust Cleans Arsenic From Drinking Water"

The United States Geological Survey’s fact sheet on "Arsenic in Ground-Water Resources of the United States"

The World Health Organization on "Arsenic in Drinking Water"