Using chemistry to further boost recycling rates

This chemical recycling method could help to keep waste polyester out of landfill

Spotted: Combatting plastic waste has become one of the most important pillars in achieving a more sustainable future. And yet, scaling simple and cost-efficient solutions – particularly when it comes to plastic recycling – has proved a challenge. Recently, however, a group of researchers at Tokyo Metropolitan University has unveiled a new method that can be applied to the chemical recycling of both textile and plastic waste streams.

Using a mixture of alcohols combined with an inexpensive iron trichloride catalyst, the team has succeeded in depolymerising PET (polyethylene terephthalate), a polymer widely used for the manufacture of plastic bottles and clothing. By breaking the repeated “ester bonds” present in these materials, polyesters can be decomposed into their raw materials.

Conventional methods of depolymerising PET have required the application of high temperatures together with large quantities of acidic or basic substances – the result being a recycled resin laced with impurities. Because of this, it has often been more costly to produce plastic from this recycled resin than with virgin resin. By remaining acid- and base-free without generating by-products, the Tokyo solution could offer a clean, affordable alternative. 

“The efforts should provide a new possibility of chemical recycling of plastic waste,” research lead Professor Kotohiro Nomura told Springwise. Notably, the method can also be successfully applied to textile waste (a mixture of polyester and cotton), which has also been difficult to process with other chemical recycling methods.

Professor Nomura shared that moving forward, the team is focusing its attention on upcycling and testing more efficient catalysts to maximise the potential of its solution.

Written By: Duncan Whitmore