Story at a glance
- Plastic pollution is one of the most pressing issues for conservationists and environmentalists alike.
- Researchers in Sweden harvested a byproduct of plastic disposal and used it to create a new sustainable plastic.
- By incentivizing collection of this byproduct, experts hope to scale the process and create a more sustainable plastic recycling process.
Declining plastic recycling rates coupled with increased plastic pollution on the Earth’s surface and within its oceans spell concern for the planet’s health.
In an effort to combat these trends, researchers at Chalmers University of Technology in Sweden developed a recycling method that replaces all fossil raw materials used in new plastic production with carbon atoms from mixed waste. The technique has the potential to eliminate the climate impact of plastic and may rid the air of carbon dioxide.
“While fossil fuel use is the main cause of anthropogenic greenhouse gas (GHG) emissions, and a transition away from the use of such fuels is essential to limit the global temperature increase to 1.5 [degrees celsius]the production and use of materials such as plastics, cement and steel entail significant GHG emissions,” researchers explained in the Journal of Cleaner Production.
They hypothesized carbon atoms in plastic waste serve as an important untapped resource. These existing resources are currently incinerated or find their way to landfills. Thermochemical technologies can target this waste carbon and use it as a raw material to produce plastics of similar quality to those created with fossil fuels.
According to investigators, enough of these atoms already exist to meet the needs of all global plastic production. The atoms can be harvested from waste with or without food residue.
“If the process is powered by renewable energy, we also get plastic products with more than 95 percent lower climate impact than those produced today, which effectively means negative emissions for the entire system,” said co-author Henrik Thunman in a press release.
To complete the process, the carbon atoms would need to be heated to 600 to 800 degrees celsius, converting the material to gas. Adding hydrogen to this gas can replace the building blocks of plastics and researchers are working to ensure the gas can be used and converted in the same factories currently used to manufacture plastic.
This process can also be powered by renewable sources like solar, wind or hydro power, making them more energy efficient than current systems in use. Experts would also be able to harvest excess heat produced in the process to offset heat production from waste incineration, thereby eliminating carbon dioxide emissions resulting from energy recovery, they explained.
Creating an economic structure to collect and use these carbon atoms can help incentivize this new form of recycling.
The process has already proven successful in one Swedish plant in collaboration with Borealis, a plastic manufacturer.
“Global application of advanced thermochemical recycling technologies has great potential: less energy than used in today’s material system may likely be required, and carbon emissions can be reduced using different energy sources, leading to near-zero carbon emissions with renewable energy,” authors concluded .
More research is needed to better understand best deployment strategies and determine their economic and energy implications.
Published on Jul. 01, 2022