I just want to ask if we could apply this as an Investigatory Project. Actually, we've done this before but our professor told us that we must not do it at present 'cause it is just simply obvious that it'll not work. Our methodology accounts to dry the chopped peels under the sun for a week and we will put the dried peels to the diff water samples for a day such that of river water, canal water and that had been used for washing dishes. Thereafter, we will just filter the water into a cloth and pail. Then the before and after samples will then be examined if there's the removal of metals or coliform bacteria? Any improvisation you can suggest please.
Published March 11, 2011
This story is part of a National Geographic News series on global water issues.
Banana peels are no longer just for composting or comedy shows: New science shows they can pull heavy metal contamination from river water.
Metals such as lead and copper are introduced to waterways from a variety of sources, including agricultural runoff and industrial wastes. Once there, heavy metals can contaminate soils and pose health risks to humans and other species. Lead is known to affect the brain and nervous system.
Traditionally, water quality engineers have used silica, cellulose, and aluminum oxide to extract heavy metals from water, but these remediation strategies come with high price tags and potentially toxic side effects of their own. They work as extractors due to the presence of acids such as those found in the carboxylic and phenolic groups, which attract metal ions.
Bananas, on the other hand, appear to be a safe solution. Banana peels also outperform the competition, says Gustavo Castro, a researcher at the Biosciences Institute at Botucatu, Brazil, and a coauthor of a new study on this new use of the fruit’s peel.
For the study, Castro and his team dried and ground banana peels, then combined them in flasks of water with known concentrations of metals. They also built water filters out of peels and pushed water through them.
In both scenarios, “the metal was removed from the water and remained bonded to the banana peels,” Castro said, adding that the extraction capacity of banana peels exceeded that of other materials used to remove heavy metals.
Previous work has shown that other plant parts—including apple and sugar cane wastes, coconut fibers, and peanut shells—can remove potential toxins from water.
Don’t Try This at Home
Castro doesn’t advise the use of banana peels for home water purification. For starters, the concentration of heavy metals in tap water is usually negligible. Also, while putting banana peels in contact with water will likely remove some metals, the average person isn’t likely to be able to measure success.
Castro said his study findings are most likely to be useful in industrial settings.
The new study appears in Industrial & Engineering Chemistry Research, a journal of the American Chemical Society.
The World's Water
The world's increasing population and development of agricultural land are putting pressure on the Earth's limited freshwater supplies. Find out what's at stake and how you can help.
Learn more about the world's water challenge with photos, stories, videos, and more.
You might be surprised to see how the daily choices you make affect critical watersheds around the world.
Water Currents, by Sandra Postel and Others
Arizona's Verde River gets a boost from an innovative partnership.
Farmers in the Verde River Basin employ new technology to benefit a desert environment.
Funny viral video series hopes to get people thinking about the importance of water.
The Future of Food
How do we feed nine billion people by 2050, and how do we do so sustainably?
We've made our magazine's best stories about the future of food available in a free iPad app.
Stories From Experts in the Field
National Geographic Fellow Zeb Hogan tells us what needs to happen in order to save the region's giant fish.
Sunita Narain tells us how one remote village is setting an example for the rest of the country—and world.
National Geographic Freshwater Fellow Sandra Postel describes one of the biggest success stories in urban water management.