ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2024 13 SUSTAINABILITY BRIEF UPCYCLED CARBON FIBERS Scientists at the Korea Institute of Science and Technology (KIST) created a method that recycles more than 99% of carbon fiber reinforced plastics (CFRP) in a short amount of time by using water in a supercritical state. Supercritical water has a high polarity, diffusivity, and density that allows it to selectively remove only the epoxy impregnated in the CFRP to obtain recycled carbon fiber. The researchers achieved a highly efficient recycling system without using any catalysts, oxidants, or organic solvents—using only supercritical water. They also found that adding glycine to supercritical water can upcycle CFRP into recycled carbon fiber doped with nitrogen atoms. This upcycled carbon fiber has better electrical conductivity than conventional recycled carbon fiber. This is the first time that a single recycling process has been used to simultaneously recycle and upcycle CFRP within tens of minutes, controlling the structure and properties of the recycled fiber. Until now, recycled CFRP fibers have been limited to use as fillers in composites due to their inhomogeneous properties. In comparison, the team’s upcycled carbon fibers performed as well as or better than graphite in coin cell evaluations when applied as electrodes in e-mobility batteries. www.kist.re.kr. NEW MATERIAL CAGES GREENHOUSE GASES An international team of researchers led by Heriot-Watt University, Scotland, developed a new type of porous material that can store carbon dioxide and other greenhouse gases. The team used computer modeling to accurately predict how their specially structured molecules would assemble themselves into the new type of porous material. They created hollow, cage-like molecules with high storage capacities for greenhouse gases like carbon dioxide and sulfur hexafluoride, which is a more potent greenhouse gas than carbon dioxide and can last thousands of years in the atmosphere. The specialized cage molecules were assembled using other cages to create a new type of porous material that the scientists say is the first of its kind with its porous cage-of-cages structure. “Combining computational studies like ours with new AI technologies could create an unprecedented supply of new materials to solve the most pressing societal challenges, and this study is an important step in this direction,” says lead researcher Marc Little. He added that molecules with complex structures could also be used to remove toxic compounds known as volatile organic compounds from the air and could play an important role in medical science. www.hw.ac.uk. Researchers at Concordia University, Montreal, are studying algae as a power source that not only produces zero carbon emissions but actually removes carbon. The method involves extracting energy from the photosynthesis of algae suspended in a special solution and housed in small power cells. The team says the cells can generate enough energy to run ultra-low power devices such as sensors. www.concordia.ca. Conceptual diagram of utilizing waste CFRP as battery electrode materials. Courtesy of KIST. Porous materials expert Dr. Marc Little is an assistant professor at Heriot-Watt University’s Institute of Chemical Sciences.
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