Coal to concrete? Scientists report chemical breakthrough
E&E News | Parker Shea Feb 2020
Rice University researchers have discovered a way to convert coal, petroleum coke, plastic or any carbon-based waste into a substance that they say can slash emissions cheaply from some of the most energy-intensive industries, such as concrete and cement manufacturing. The resulting “flash graphene” can bind concrete, allowing builders to theoretically use less of it and cement in construction and reduce energy use in manufacturing overall, according to a study published in the journal Nature last week. In the past, graphene has been too expensive to manufacture at mass scale, but the researchers say they found a cheaper way to produce it. Because it is stronger than steel, flash graphene could be used in a range of other applications, including fortifying plastics. The new process takes 10 milliseconds and involves using a small reactor to “flash” a powerful electrical pulse through just about any kind of carbon-based waste — from banana peels to chunks of coal — to produce high-quality graphene. “This is a big deal,” said Rice University chemist James Tour, who was lead author on the paper. With a Department of Energy grant, Tour said he is planning to scale up the process. “If you take most forms of carbon, it’s going to be taken up by plants, and it’s eventually going to form CO2 when it’s burned. But here, once we turn it into graphene, it stays graphene,” Tour told E&E News. Graphene is not toxic to humans, and graphene carbon molecules remain in that chemical structure for hundreds of years, Tour said. In comparison, food and plastic waste can degrade into gaseous carbon dioxide for decades. […] By some estimates, concrete production accounts for up to 8% of global annual CO2 emissions. The concrete and cement industry claims that number might be closer to 5%. A concentration of as little as 0.1% of flash graphene in the cement used to bind concrete could lessen its environmental impact by a third, according to the research.