Mining processes, runoff from farms, and industrial wastes can all put heavy metals such as lead and copper into waterways. Heavy metals can have adverse health and environmental effects. Current methods of removing heavy metals from water are expensive and some substances used in the process are toxic themselves. Previous work has shown that some plant wastes, such as coconut fibers and peanut shells, can remove these potential toxins from water. Gustavo Castro, and colleagues at São Paulo State University in Brazil, wanted to find out whether minced banana peels could also act as water purifiers.

The topic is covered in the latest episode in the American Chemical Society's award-winning Global Challenges / Chemistry Solutions podcast series.

“I chose to work with banana peels because I have heard for a long time that we usually throw out the best part of the fruit and that most of the nutrients and proteins are in parts not used by us, such as the peels. From there, I decided to make an initial experiment to determine the chemical composition of the peel,” said Castro.

The researchers found that minced banana peel could quickly remove lead and copper from river water as well as or better than many other materials. They say that banana peels can be used up to 11 times without losing their metal-binding properties. The scientists add that banana peels are very attractive because of their low cost and because they don’t have to be chemically modified in order to work.

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