Plastic waste is an increasingly important problem. Up to now, only 9% of the plastics ever produced have been recycled. The rest remain on earth for hundreds of years. They wash out to the ocean to become rubbish, harm wildlife and break down into small plastics that can enter the human brain and other parts of our bodies.

Recently, scientists have developed a new method to break down plastic waste with the help of water in the air. The researchers mixed a special metal and activated carbon (活性碳) with PET, the most common type of polyester (聚酯) plastic. Then they heated the mixture. After a short time, this broke the chemical connections in the polyester. Next, when the team left the material in the air, the mixture turned into TPA, a polyester material, and acetaldehyde, an industrial chemical. Finally, these valuable chemical materials were recycled.

After the first success, researchers tested the method on different plastics and found it worked on polyester plastic only. That meant they didn’t need to separate different kinds of plastics. Also, when they added water, it stopped working because the amount (数量) of water in the air was just right.

The team’s next plan will be to use the method widely in industry.

“It’s hopeful that our technology can hugely reduce plastic pollution, lower the environmental footprint of plastics and help materials be reused instead of being thrown away,” researchers said. “It’s a leap towards a cleaner, greener future, and it shows how creative chemistry can solve world challenges in a way that joins hands with nature.”