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Nanorust and Arsenic (Image 1)
Nanorust and Arsenic (Image 1)
"Nanorust" particles, nanoparticles of magnetite, a common magnetic mineral (also known as lodestone). These nanoparticles are made using a bench-top chemical reaction, and have a very narrow distribution of sizes, tuned to optimize their magnetic properties. At these sizes, each nanorust particle acts like a little bar magnet, where the direction of "north" fluctuates all the time. These fluctuations are due to the small size of the nanoparticles, and together with a surfactant coating (the little black wiggles), they keep the nanoparticles from clumping together and falling out of the solution.
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The discovery of unexpected magnetic interactions between nanoparticles of rust was made by researchers from Rice University's Center for Biological and Environmental Nanotechnology (CBEN). The discovery could lead to a revolutionary, low-cost technology for cleaning arsenic from drinking water. Arsenic is a colorless, odorless, tasteless element that can lead to skin discoloration, sickness, cancer and death.
This image depicts how the particles bind with arsenic in water. The particles of arsenic-laden rust are then drawn out of the water by handheld magnets, leaving clean drinking water.
Arsenic-poisoned drinking water is a problem worldwide, and it is acute in the developing world. In Southeast Asia, 65 million people are at risk for arsenic-related health problems due to contaminated drinking water, this according to 2005 World Bank statistics.
Many rural communities in Southeast Asia rely on shallow underground "tube wells." The wells were installed in the 1970s to reduce dependence on bacteria-infested waterways and ponds, but many of the wells have turned out to be a source of naturally occurring arsenic.
CBEN's purification technology is simple and requires no electricity, which many of these communities lack. The nanoparticles used in the CBEN experiments were expensive, so Rice researchers are working to develop less-costly production methods that will use household rust and olive oil, and will require no more facilities than a kitchen with a gas cook-top. (Date of Image: 2006) [Image 1 of 3 related images. See Image 2.]
Credit: Rice University Public Affairs/News and Media Relations
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