New Method Makes an Economic Case for Recycling Polycotton

Half of the world’s fabric waste produced each year could be recycled with a method first developed nearly a century ago.

Humanity produces 113 million tons of textile waste per year as of 2021, and about half of that is polycotton, a mix of polyester fiber and cotton that is not easily separated for recycling. Most processes that can break down the cotton damage the polyester and vice versa. But acid hydrolysis of polycotton can break down the cotton portion into glucose at room temperature and pressure, leaving the polyester fibers free for recycling, a new pilot-scale demonstration using real waste clothing shows.

“There is an enormous amount of valuable feedstock that is now not utilized,” says Gert-Jan Gruter, a professor of industrial sustainable chemistry at the Univ. of Amsterdam and the chief technology officer for the sustainable plastics company Avantium.

Gruter and his team were initially motivated by finding non-food sources for the building blocks of bioplastics (particularly glucose), which originate from corn in the U.S. and wheat in Europe. They have been working on cellulose hydrolysis in wood for a decade, seeking ways to separate the lignin and hemicellulose in wood from the cellulose that can be broken down into glucose. That work has led to a concentrated acid process, which hydrolyzes cellulose at room temperature without degrading the ultimate product, glucose.

Along...