Researchers Develop Method For Upcycling Plastic Waste Into Soap
Arthur T Knackerbracket writes:
Arthur T Knackerbracket has processed the following story:
Plastics and soaps tend to have little in common when it comes to texture, appearance, and, most importantly, how they are used. But there is a surprising connection between the two on a molecular level: The chemical structure of polyethylene-one of the most commonly used plastics in the world today-is strikingly similar to that of a fatty acid, which is used as a chemical precursor to soap. Both materials are made of long carbon chains, but fatty acids have an extra group of atoms at the end of the chain.
Guoliang "Greg" Liu, associate professor of chemistry in the Virginia Tech College of Science, had long felt this similarity implied that it should be possible to convert polyethylene into fatty acids-and with a few additional steps to the process-to produce soap. The challenge was how to break a long polyethylene chain into many short-but not too short-chains and how to do it efficiently. Liu believed there was the potential for a new upcycling method that could take low-value plastic waste and turn it into a high-value, useful commodity.
[...] With the help of Zhen Xu and Eric Munyaneza, two Ph.D. chemistry students in Liu's lab, Liu built a small, oven-like reactor where they could heat polyethylene in a process called temperature-gradient thermolysis.
At the bottom, the oven is at a high enough temperature to break the polymer chains, and at the top, the oven is cooled to a low enough temperature to stop any further breakdown. After the thermolysis, they gathered the residue-similar to cleaning soot from a chimney-and found that Liu's hunch had been right: It was composed of "short-chain polyethylene," or more precisely, waxes.
[...] "Our research demonstrates a new route for plastic upcycling without using novel catalysts or complex procedures. In this work, we have shown the potential of a tandem strategy for plastic recycling," said Xu, lead author on the paper. "This will enlighten people to develop more creative designs of upcycling procedures in the future."
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