Researchers from the Bioscience Institute at Botucatu, Brazil, said that the peels can outper form even conventional purifiers such as aluminum oxide, cellulose and silica. These have potentially toxic side effects and are expensive.
The team's method follows previous work that showed that plant parts, such as apple and sugar cane wastes, coconut fibers and peanut shells, can remove toxins from water. These natural materials contain chemicals that have an affinity for metals.
(2) In the process, the researchers dried the peels in the sun for a week, ground them and added them to river water containing known concentrations of copper and lead.
They found that the peels absorbed 97 per cent of the met als after just one hour. The peels were tested in the lab and worked perfectly.
Eventually their efficiently reduces, at which point the metals should be removed from the peels so that they can be disposed of safely. In addition, they said that although the peels were tested only on copper and lead, the material could also work on cadmium, nickel and zinc.
But they warned that this sort of filter is better suited to industrial purposes and cannot be used for water purifica tion at home as the extraction capacity of banana peels de pends on the particle on the particle size of the heavy met als-and this is difficult to measure.
Dimitris Kalderis, from the Technical University of Crete, Greece, said: "The results are very promising and the banana peel processes has proven to be a cost-effective and quick alternative to conventional methods, The knowledge is there, what we need now is in novation and construction."
Baca Juga: Contoh Soal UTBK Bahasa Inggris dan Pembahasan, 'Restating Sentence'
Pertanyaan
1. What does the word "these" in "These have potentially toxic...." (paragraph 1) refer to?
A. Conventional purifier
B. Heavy metals