Aug 3 2018
A newly reported study by a Dickinson College chemistry professor has furthered one’s knowledge of the power of vegetable and fruit peels to eliminate pollutants, such as heavy metals and dyes, from water.
Cindy Samet, professor of chemistry, and her students conducted water purification experiments using seeds and peels from over a dozen varieties of foods - from pumpkin and okra to lemon and banana - and discovered that they eliminated lead, methylene blue, and copper by the process of adsorption, a chemical bonding of the pollutant molecules to the surface of the peels.
The research titled “Fruit and Vegetable Peels as Efficient Renewable Adsorbents for Removal of Pollutants from Water: A Research Experience for General Chemistry Students,” was reported in the Journal of Chemical Education. In 2015, Suresh Valiyaveettil, Samet’s coauthor and a professor at the National University of Singapore, published the original study on which Samet based her course. His research involved the analysis of the potential of Hami melon, avocado, and dragon fruit peels to eliminate pollutants from water. In the video, Samet shows how dried avocado peel has the ability to adsorb huge amounts of methylene blue onto its surface within a few hours.
Samet cleaned the surface of the fruit by following Valiyaveettil’s protocol, which involves first boiling the seeds/peels to remove soluble surface impurities. Then, the peels were dried, crushed, and placed in a solution that contained pollutants. The results showed that while lemon seeds eliminated 100% percent of lead ions, its peels eliminated 96.4%. Okra peels also eliminated 100 percent of lead ions, and its seeds eliminated 50%.
The results expand on what we know about fruit and vegetable peels as an organic, renewable, low-cost method of removing pollutants from water. We replicated the results from Suresh’s lab with avocado and then studied never-before-tested fruits and vegetable peels and seeds. This is exciting because it is likely that this method of purification can make its way from lab to kitchen.
Cindy Samet, Professor of Chemistry
Samet can already visualize the use of dried peels in the kitchen as a natural, at-home option to eliminate impurities from drinking water. However, the focus of Samet’s classroom project was on industrial effluents such as heavy metal ions and dyes. Samet anticipates that on a large scale, the peels could someday turn out to be an affordable solution in parts of the world with declining supplies of clean, safe drinking water.