Materials

New catalyst converts common plastic waste into fuels and wax

New catalyst converts common p...
Researchers in Japan have developed a new catalyst that could make it easier to recycle waste plastic into new products
Researchers in Japan have developed a new catalyst that could make it easier to recycle waste plastic into new products
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Researchers in Japan have developed a new catalyst that could make it easier to recycle waste plastic into new products
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Researchers in Japan have developed a new catalyst that could make it easier to recycle waste plastic into new products

As useful as plastics are in our everyday life, they’re difficult to recycle, meaning most ends up in landfill or polluting the environment. Now, researchers in Japan have used a novel catalyst to recycle a common plastic into useful products like fuel and wax.

By design, plastics are extremely resistant to chemical reactions. That makes them great for bottles and containers for chemicals, but on the flipside it makes them hard to break down when they need to be disposed of. For example, thermal recycling processes, require temperatures of between 300 °C and 900 °C (572 °F and 1,650 °F), which obviously consumes a whole lot of energy.

So for the new study, researchers at Tohoku and Osaka City Universities set out to find a new catalyst that could break plastics down at lower temperatures. The team found that combining ruthenium and cerium dioxide worked most effectively, creating a catalyst able to recycle polyolefinic plastics at just 200 °C (392 °F).

“Our approach acted as an effective and reusable heterogeneous catalyst, showing much higher activity than other metal-supported catalysts, working even under mild reaction conditions,” say Masazumi Tamura and Keiichi Tomishige, co-authors of the study. “Furthermore, a plastic bag and waste plastics could be transformed to valuable chemicals in high yields.”

The researchers say they were able to convert about 92 percent of the waste plastic into useful materials. As much as 77 percent of it became a liquid fuel, while 15 percent yielded wax, which should help make plastic recycling a more viable prospect.

This is far from the only plastic recycling method on the horizon. Just a few weeks ago a team from UC Berkeley reported a new process to turn polyethylene into a clingy new adhesive, while others are designing new plastics from the ground up to be easily recyclable.

The new study was published in the journal Applied Catalyst B: Environmental.

Source: Osaka City University

8 comments
8 comments
michael_dowling
What about the CO2 released when the "fuel" is burned?
FB36
Cars and other light vehicles are already well on their way to become fully electric but what about all large trucks, trains, ships, agriculture/construction/military vehicles which run on diesel fuel?
Our world desperately need to start producing biodiesel fuel at large/global scales (to make all diesel vehicles carbon-neutral)!
Produce biodiesel fuel from what?
How about all kinds of waste/trash/biomass/sewage?
Username
FB36 - there are already electric versions of the vehicles you mention that are in production.
ljaques
OK, cool. They don't give away Cesium (a buck a mg) or Ruthenium (a buck a gram), so how much does this process cost? I suppose that the CO2 given off when it's burned will join with the CO2 that all humans produce whenever they exhale while polluting the air with their fireplaces, which are as much as 400 times that put out by an ICE vehicle or gas furnace. I like the other research which turned it back into oil for reuse. What happened with that?
jerryd
They exaggerate how much energy is required to convert them by heating alone which is about 10% which can be waste heat after making power with the gases that are not valuable with the rest mostly gasoline, diesel fractions taken off by temp to select.
They also don't say if PET, etc plastics as you treat different plastics different ways.
'Plastic to Oil'.
yu
how well does this work with co-mingled plastics as most waste streams are? Also the pigments and dyes in plastics?
Karmudjun
I hope the "effective and reusable catalyst" proves scalable - it would be nice to diminish the amount of plastic in our diet by pulling it out of the ocean, the water supply, and garbage dumps. I would like to see 100% of plastic reused so we quit adding it to the soil. At some point, nature will prove Darwin correct by a single cell organism evolving to use plastic as food - then we will fight more than termites and carpenter ants and other wood eating organisms - but we will be inundated by plastic and oil scavenging organisms too! We need more or this research to reduce the chances of nature fixing our problem of excessive plastic waste.
JohnWhite
ljaques so the thing is ruthenium and cerium dioxide are catalysts. So you get them back after - that's what a catalyst is about. They are not reagents. https://en.wikipedia.org/wiki/Catalysis