BENGALURU : A research group led by Washington State University (WSU) scientists has found a way to turn daily plastic waste products into jet fuel. In a new paper published in the journal Applied Energy, WSU's Hanwu Lei and colleagues melted plastic waste at high temperature with activated carbon, a processed carbon with increased surface area, to produce jet fuel.

"Waste plastic is a huge problem worldwide," said Lei, an associate professor in WSU's Department of Biological System Engineering, in a press statement on Tuesday. "This is a very good, and relatively simple, way to recycle these plastics," he added.

In the experiment, Lei and colleagues tested low-density polyethylene and mixed a variety of waste plastic products like water bottles, milk bottles and plastic bags, and ground them down to around three millimeters, or about the size of a grain of rice. The plastic granules were then placed on top of activated carbon in a tube reactor at a high temperature, ranging from 430 degree Celsius to 571 degrees Celsius. The carbon is a catalyst, or a substance that speeds up a chemical reaction without being consumed by the reaction.

"Plastic is hard to break down," Lei said. "You have to add a catalyst to help break the chemical bonds. There is a lot of hydrogen in plastics, which is a key component in fuel."

Once the carbon catalyst has done its work, it can be separated and re-used for the next batch of waste plastic conversion. The catalyst can also be regenerated after losing its activity. After testing several different catalysts at different temperatures, the best result produced a mixture of 85 percent jet fuel and 15 percent diesel.

According to the Environmental Protection Agency, landfills in the U.S. received 26 million tons of plastic in 2015, the most recent year for which statistics are available. China has recently stopped accepting plastic recycling from the U.S. and Canada. Conservative estimates by scientists say that at least 4.8 million tons of plastic enters the ocean each year worldwide.

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