UC Irvine Scientists Develop New Method in Converting Plastic Garbage to Liquid Fuel

A team of researchers from the University of California, Irvine and the Shanghai Institute of Organic Chemistry (SIOC) in China has devised a new method of converting millions of tons of plastic garbage into liquid fuels.

The new method, described in a paper published in the journal Science Advances, provides a milder and more efficient way of recycling plastics.

At present, scientists use caustic chemicals known as radical or heating the material to over 700 degrees Fahrenheit in order to break down the chemical bonds of polymer molecules.

For the new method, dubbed as cross-alkane metathesis, researchers used specific types of hydrocarbon molecules called alkanes to break down the strong bonds of polyethylene, scrambling and separating polymer molecules into other useful compounds. Using alkanes as cross metathesis partners, different types of polyethylene with various molecular weights can undergo complete conversion into useful liquid fuels and waxes.

"Synthetic plastics are a fundamental part of modern life, but our use of them in large volume has created serious environmental problems," said UCI chemist Zhibin Guan and co-author of the study, in a press release. "Our goal through this research was to address the issue of plastic pollution as well as achieving a beneficial outcome of creating a new source of liquid fuel."

Also, alkanes are compatible with various polyolefin additives, making common plastic wastes, such as postconsumer polyethylene bottles, bags and films convertible even without any pretreatment.

Polyethylene is the simplest type of polymer and is the most common commercially available form of plastics. It is used to make grocery bags, shampoo bottles, children's toys and even bullet-proof vests.

The substance needed for the cross-alkane metathesis is the byproducts of oil refining, making it readily available.

The US-China joint study are still working on a few issues, which include s increasing the catalyst activity and lifetime, decreasing the cost, and developing catalytic processes to recycle other plastic trash, to make their process more efficient.