Dutch innovators sever the head of the polycotton monster

Researchers at the University of Amsterdam (UvA) have come up with an innovative way to recycle polycotton textile waste.

The new process, which was developed in cooperation with chemical recycler Avantium, starts by removing all cotton from the fabric using super-concentrated hydrochloric acid at room temperature. The cotton is converted into glucose, which can be used as a feedstock for biobased products such as renewable plastics.

The remaining polyester fibres can be reprocessed using available polyester recycling methods, explains Gert-Jan Gruter who heads the research at the Industrial Sustainable Chemistry group. He is grateful that various industry players, including textile sorting and recycling company Wieland, are supporting his efforts. 

Proprietary tech

UvA PhD student Nienke Leenders performed experiments using Avantium’s pilot plant for its proprietary ‘Dawn Technology’ – originally developed to convert wood into glucose and lignin. Its key feature uses highly concentrated hydrochloric acid (43% by weight) at room temperature.

Leenders tested batches of post-consumer polycotton textile waste in the pilot plant. He found the cotton cellulose could be ‘fully hydrolysed’ into glucose under industrially relevant conditions. The polyester part of the fabric remained intact and was easily separated. The trials demonstrated high glucose yields, indicating scalability and cost-effectiveness.

Replacing PET bottles?

Leenders and Gruter report that the cotton-derived glucose from the process can be used in a wide range of industrial applications. This includes polymers, resins and solvents. They envision the output could be used by Avantium to produce its lead product 2,5-furandicarboxylic acid. This would offer a renewable alternative to polyethylene bottles.

More importantly, Gruter underlines his team’s new process also enables the ‘complete recycling’ of polyester from polycotton. It can be formed into virgin polyester, as has been established in tests by chemical recycling specialist CuRe.