Chemists from the Rice University lab have introduced a new process for turning bulk quantities of “trash”, which contains carbon, into valuable graphene flakes.
This process is quick and cheap. The “flash graphene” is made in 10 milliseconds by heating carbon-containing materials to 3,000 Kelvin (2,726.85 °C).
The source material can be nearly anything with carbon content. Food waste, plastic waste, petroleum coke, coal, wood clippings and biochar are prime candidates.
“This is a big deal,” Rice University chemist James Tour said. “The world throws out 30% to 40% of all food, because it goes bad, and plastic waste is of worldwide concern. We’ve already proven that any solid carbon-based matter, including mixed plastic waste and rubber tires, can be turned into graphene.”
The flash process happens in a custom-designed reactor that heats material quickly and emits all non-carbon elements as gas. “When this process is industrialized, elements like oxygen and nitrogen that exit the flash reactor can all be trapped as small molecules because they have value,” Tour said.
He said the flash process produces very little excess heat, channeling almost all of its energy into the target. “You can put your finger right on the container a few seconds afterwards,” Tour said. “And keep in mind this is almost three times hotter than the chemical vapor deposition furnaces we formerly used to make graphene, but in the flash process, the heat is concentrated in the carbon material and none in a surrounding reactor.
“All the excess energy comes out as light, in a very bright flash, and because there aren’t any solvents, it’s a super clean process,” he added.