Super absorbent polymer made from recycled and biodegradable waste products fights drought in South Africa

10-Aug-16

Using orange peel and avocado skins, a student from Johannesburg has created a super absorbent polymer (SAP) capable of storing reserves of water hundreds of times its own weight, forming reservoirs that would allow farmers to maintain their crops at minimal cost. The polymer has the added benefit of sustainability as it uses recycled and biodegradable waste products and helps tackle the drought situation in Soiuth Africa.
Johannesburg schoolgirl Kiara Nirghin, 16, recently won the Google Science Fair's Community Impact Award for the Middle East and Africa with her submission "No More Thirsty Crops."

She describes the process as "trial and error," with a lot of experimentation before alighting on the perfect formula. "I started researching what an SAP was, and what they all had in common was a chain molecule polysaccharide," Nirghin recalls. "I found that orange peel has 64% polysaccharide and also the gelling agent pectin, so I saw it as a good (option). I used avocado skin due to the oil." The teenager combined the skin and peel and left the mixture in the sun, where they reacted together to form the powerfully absorbent polymer.

As a regional winner, Nirghin has been assigned a mentor from Google to work with her on developing the polymer, and hopes it could be tested in the field. She will soon discover if she is one of the tech giant's sixteen global finalists. "I think it works," says Dr. Jinwen Zhang, a professor of materials engineering at Washington State University, who is developing absorbent hydrogels to address drought. "Using waste products for low-cost feedstock for large volume is definitely worth further investigation."