Snubbed by industries, restaurants, and even housewives, banana peels could soon rise to the top.
They found that, from a powder made from banana peels, it is possible to decontaminate waters with heavy metals in an effective and cheap way.
The project is by Milena Boniolo, PhD in Chemical Sciences from UFSCar (Federal University of São Carlos, São Paulo), who had the idea when she saw a story about banana residues in Brazil.
"In Greater Sao Paulo alone, about four tons of banana peels are generated every week. And that's only in restaurants," says the researcher.
Boniolo is already working on strategies for cleaning water, but they were expensive methods – such as magnetic nanoparticles – that exclude use in small industries.
With banana peels, there is no such problem. As the product has very little commercial interest, and there are companies willing to donate them.
The method takes advantage of the basic principles of chemistry: opposites attract.
In banana peel, there are a large number of negatively charged molecules. They can attract heavy and positively charged metals.
For this to happen, however, we must take advantage of these properties in the banana. This is done very simply and almost without consuming energy.
"I started doing it at home. It's very easy," says Boniolo.
Banana peels are placed on trays and dried in the sun for almost a week. This material is then crushed and then passed through a special sieve. This ensures that the particles are uniform.
The result is a fine powder that is added to the contaminated water. For every 100 ml of contaminated water, 5 mg of banana powder is used.
In the laboratory, the decontamination rate is at least 65% each time the water went through the process. That is: if it is put into practice again and again, it is possible to achieve high levels of "cleanliness".
The project, which was presented in the researcher's thesis at IPEN (Institute for Energy and Nuclear Research), was designed with uranium.
However, according to Boniolo, it is also effective with other metals such as cadmium, lead and nickel – widely used in industry. In addition to invitations to present the idea in Brazil and England, chemistry has also won the Young Scientist Award.
Now, he says, partners must be found to enable the use of the technique on an industrial scale.
Authors: Val
