Washington: Millions of tons of plastic garbage pollute our world. What if we could turn them into fuel instead? That’s the ambitious plan of a team of scientists from the University of California, Irvine (UCI), and the Shanghai Institute of Organic Chemistry (SIOC) in China. The technique involves breaking down the plastic to a molecular level to turn it into a readily usable fuel similar to diesel.
The source material is the most common type of plastic, polyethylene, which is predicted to reach a global annual demand of nearly 100 million metric tons by 2018. Polyethylene, which is made from crude oil, is the main ingredient of PET (polyethylene terephthalate), used the make the majority of plastic bottles.
Recyled PET can be used to make new plastic containers or to create synthetic fibers known as polyester (which is normally made from brand new PET), but this process requires a virtuous system of disposal, collection, and chemical transformation that is not always available. In 2013, the recycling rate for PET in the U.S. was just over 31 percent. The 5,764 million pounds of PET bottles produced in the same year contained just 475 million pounds of recycled materials.
Nearly half of the waste plastic worldwide is polyethylene, which doesn't degrade easily and can linger in the environment for hundreds of years. Along with other types of plastics it pollutes waterways and oceans (one large cluster is known as the Great Pacific Garbage Patch) and often gets eaten by birds and marine life.
An easy system to turn used plastic into fuel could help relieve the burden on the environment of a material that loses 95% of its value after one use cycle. “The process does not involve any harmful chemicals and does not create waste products,” explains Zhibin Guan of the University of California, Irvine.
