Nanotechnology Removes Arsenic from Well Water

By Earl Boysen, Nancy C. Muir, Desiree Dudley, Christine Peterson

Researchers are working on the use of iron oxide nanoparticles to treat arsenic contaminated water, thereby reducing the cost of the material needed to make it work.

A problem for tens of millions of people around the world is the presence of arsenic, a naturally occurring substance in soil that can dissolve in water, including well water. Robert Bunsen (the developer of the Bunsen burner) determined in the 1830s that when you mix ferric oxide with arsenic, you get a mixture that the fluids in your body and water cannot break down.

Based on Bunsen’s discovery, scientists started using iron oxide in filters to remove arsenic from water; however, the cost of this process is out of reach for many people in the third world. Researchers are working on the use of iron oxide nanoparticles to increase the surface area of iron oxide available to react with the arsenic, thereby reducing the cost of the material you need to make it work.

Although there are arsenic-contaminated wells in many countries, including the United States, more developed countries have other water sources. However, a low-cost method for removing arsenic from water could be essential in less developed countries such as Bangladesh.

In many of these countries, millions or tens of millions of people with very little income drink arsenic-contaminated well water daily. Ironically, these wells were drilled so that people could avoid drinking from contaminated surface water sources.

A key aspect of research efforts is to see how theories developed in the lab will work in the field. For example, researchers at Rice University are currently working to develop a low-cost method of using iron oxide nanoparticles. These researchers are currently performing field evaluations of the iron oxide nanoparticle method with arsenic-contaminated water in wells at Guanajuato, Mexico.