A scientific breakthrough will turn 10 million tons of peanut shells into graphene

According to a report on the scientific website Science Alert, a method has been developed to convert this biological waste into carbon materials with properties similar to graphene – a move that can make it of real value to humans. According to the data, the production of peanuts in the world produces more than 10 million tons of shells every year, which are usually disposed of using waste removal mechanisms.

The report states that graphene is a carbon material that is sometimes considered a “miracle material”, thanks to its high strength, very low weight and ability to conduct heat and electricity effectively. Today it is already in use, and is expected to significantly upgrade the field of consumer electronics in the future. However, the production of graphene in large volumes is a complex and expensive process, so the development of alternatives may lead to a significant improvement in areas such as energy, information storage and other advanced technologies.

The new study, conducted by a team from the University of New South Wales (UNSW) in Australia, found that peanut shells can be used as a source for producing graphene in a cheaper and more environmentally friendly way than some of the existing methods.

The basis of the process is lignin – a natural polymer rich in carbon found in most plants. Although its presence in peanut shells was known, the researchers were required to develop an efficient method to process it. As part of the research, different methods were examined for preparing the barks for lignin production, before applying a rapid heating process. In this method, an electric flash is used that raises the temperature to over 3000 degrees Celsius for a very short period of time, and causes the carbon atoms to rearrange themselves in a graphitic structure.

Along with the heating, it was found that the preparation phase of the material is critical: the most effective method involved indirect heating to about 500 degrees Celsius for five minutes, and then a short heating at a higher temperature. This process makes it possible to remove impurities and turn the shells into charcoal – a material rich in carbon and with a higher conductivity than the original material.

“This process is essential for removing impurities and obtaining a material as rich in carbon as possible, while reducing defects in the final graphene and ensuring that it is a single layer of atoms,” Yao said. He added: “Thus it is possible to guarantee optimal properties of electrical and thermal conductivity.”

Although attempts have been made in the past to produce graphene from peanut shells, the current research shows that more precise control of the process significantly improves the quality of the product. However, the researchers emphasize that the technology is still not perfect: the resulting graphene is of high quality, but often consists of several layers that are not uniformly arranged. In addition, it may be three to four years before commercial implementation.

The work to improve the method will continue, and at the same time the possibility of applying the process to other types of biomass is also being examined. “We plan to test additional materials such as coffee beans, banana peels or any other source of high-quality carbon that can be converted into graphene,” Yao said. According to him, in light of the high availability of organic materials, the research presents a balance between energy efficiency, the quality of the graphene and the economic viability of the process.