Tamarind shells, a tropical fruit eaten around the world, are discarded during food production. Bulky, tamarind shells occupy a considerable place in landfills where they are disposed of as agricultural waste.
However, a team of international scientists led by Nanyang Technological University in Singapore (NTU Singapore) have found a way to solve the problem. By processing the carbon-rich tamarind shells, scientists converted the waste into carbon nanosheets, which are a key component of supercapacitors – energy storage devices used in automobiles, buses, electric vehicles, trains. and elevators.
The study reflects NTU’s commitment to addressing humanity’s great sustainability challenges as part of its 2025 strategic plan, which aims to accelerate the translation of research findings into innovations that mitigate our impact on l ‘environment.
The team, made up of researchers from NTU Singapore, the University of Applied Sciences of Western Norway in Norway and Alagappa University in India, believe that these nanosheets, once extended, could be an environmentally friendly alternative to their counterparts. industrially produced, and reduce waste at the same time.
Assistant Professor (Steve) Cuong Dang, NTU School of Electrical and Electronic Engineering, who led the study, said: in terms of porous structure and electrochemical properties. The nanosheet manufacturing process is also the standard method for producing activated carbon nanosheets. “
Professor G. Ravi, head of the physics department, who co-authored the study with assistant professor Dr R. Yuvakkumar, both of Alagappa University, said: “The use of tamarind shells may reduce the amount of space required for landfills, especially in parts of Asia like India, one of the world’s largest producers of tamarind, which also struggles with waste disposal. “
The study was published in the peer-reviewed scientific journal Chemosphere in June.
The step-by-step recipe for carbon nanosheets
To make the carbon nanosheets, the researchers first washed the tamarind fruit shells and dried them at 100 ° C for about six hours, before powdering them.
The scientists then baked the powder in an oven for 150 minutes at 700-900 degrees Celsius in the absence of oxygen to convert them into ultra-thin carbon sheets called nanosheets.
Tamarind shells are rich in carbon and porous in nature, making them an ideal material for making carbon nanosheets.
One material commonly used to produce carbon nanosheets is industrial hemp fibers. However, they do need to be heated to over 180 ° C for 24 hours, which is four times longer than that of tamarind shells, and at a higher temperature. This is before the hemp is subjected to intense heat to convert them into carbon nanosheets.
Professor Dhayalan Velauthapillai, head of the research group on advanced nanomaterials for clean energy and health applications at the University of Applied Sciences of Western Norway, who participated in the study, said: Bee. The secret of their energy storage capabilities lies in their porous structure leading to a large surface area which helps the material to store large amounts of electrical charges. “
Nanosheets derived from the tamarind shell have also shown good thermal stability and electrical conductivity, making them promising options for energy storage.
The researchers hope to explore the larger scale production of carbon nanosheets with agricultural partners. They are also working to reduce the energy required for the production process, to make it more environmentally friendly, and seek to improve the electrochemical properties of nanosheets.
The team also hopes to explore the possibility of using different types of fruit skins or shells to produce carbon nanosheets.