A new study has revealed the solution that could transform the treatment of hard-to-recycle plastics . Black plastics, often considered a challenge due to their difficulty to be identified and sorted in recycling centres, could be given a new opportunity thanks to the use of sunlight .
This breakthrough in chemical recycling highlights the potential of solar energy and the possibility of using components present in plastic waste itself, such as carbon black, which is found in many commercial products. Carbon black has been shown to be the key component in converting sunlight into heat , breaking down black polyethylene polymers and other plastics into useful monomers such as styrene.
How does the process work?
The method is surprisingly simple. The researchers have applied a circular recycling process in which black plastics, such as coffee lids or black polystyrene containers, are shredded and placed under high-intensity white LED lights or, in even more efficient conditions, under direct sunlight.
Light acts on the black carbon, transforming solar radiation into heat. This heat disintegrates the long polymer chains , separating them into smaller styrene units, which can then be recycled to produce new polyethylene products.
Promising results and improved efficiency
In the experiments, up to 53% of contaminated plastics were successfully converted into styrene monomer . Even in samples containing residues of oil, soy sauce and orange juice, the process remained remarkably efficient. However, what was most interesting was the performance of sunlight. By using focused sunlight, the conversion rate of black plastics to styrene monomer increased by up to 80%, demonstrating the power of natural radiation over LED lights.
This technique offers new hope for recycling black plastics and could play a crucial role in creating a closed recycling system that eliminates the need for external compounds or new materials for the recycling process.
Sunlight applied to recycling black plastics
The ability to harness natural light as an energy source to break down the toughest plastics and turn them into reusable resources underlines the potential of the circular economy. Researchers say this method could be key to overcoming current barriers to plastic recycling and moving towards a more sustainable future, where plastic waste is turned into useful resources instead of piling up in landfills.
This study opens up new possibilities for the treatment of black plastics and could transform the recycling industry in the coming years. As technology advances, integrating sunlight into recycling processes could be an essential tool to reduce the environmental impact of plastics.
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Source and photo: The American Chemical Society (ACS)