Textile waste is one of the fastest-growing waste streams globally, and there are limited options available to efficiently recycle end-of-life textiles into useful materials. A new recycling approach developed by Renasens (Stockholm, Sweden; www.renasens.com) utilizes supercritical CO2 to recover intact fibers from cotton, polyester and blended post-consumer textiles.
“Our process uses modified supercritical CO2 in a state where it behaves as both liquid and gas, to de-color and separate blended textiles. First, dyes and chemicals are extracted from the garment. Then the purified fibers are separated and recovered intact, ready to be spun into new yarn. Fiber quality is maintained at the macromolecular level without depolymerization and the entire process is waterless,” explains Nora Eslander, chief operating officer of Renasens. The process’ only input besides waste textiles is supercritical CO2 and a very small volume of chemicals, and extracted dyes and additives are recovered as a separate stream from the fibers.
Source: Alexander Donka/ Renasens
This approach is starkly different from current large-scale recycling processes for textile waste, which typically depend on mechanical methods that break down textiles into short, lower-quality fibers. There are also chemical-recycling approaches being deployed to depolymerize waste fibers, but these tend to be very energy-intensive. Conversely, says Eslander, Renasens’ process keeps fibers intact without the addition of water or large volumes of chemicals, while also using less energy than other approaches. “The system is modular and plugs into existing facilities. The process yields clean, separated cotton and polyester fibers with intact structural integrity, suitable for direct reintroduction into existing spinning and manufacturing infrastructure without reformulation or new equipment,” she adds.
The technology has been validated in laboratories at the KTH Royal Institute of Technology in Stockholm, and is now being scaled up for an eventual pilot plant in Borås, Sweden. “We have already begun supplying recovered fibers to manufacturers in Portugal and Italy for validation,” says Eslander. Following pilot-scale deployment, Renasens will move to large-scale commercial production and begin licensing the technology directly at customer sites.