A team at North Carolina State University (NC State) has developed an enzyme-based method for separating mixed cotton and polyester fabric in the US. They anticipate that the discovery will result in a more effective approach to recycle the materials that make up the cloth, decreasing the amount of textile waste.
If the blended fabric was dyed or given a chemical treatment to make it more wrinkle-resistant, more steps are required in the process.
In a landfill, the polyester will not biodegrade, and the cotton may take several months or more to decompose. Sonja Salmon, an associate professor of textile engineering, chemistry, and science at NC State, is the study’s lead author. She claims that the new approach allows cotton and polyester to be separated in less than 48 hours.
The cellulose in cotton was broken down using a “cocktail” of enzymes in a gently acidic solution. According to a university press release, the goal is to break up the cellulose so that it falls out of the composite woven structure, leaving behind some microscopic cotton fiber fragments and glucose. The biodegradable result of cellulose degradation is glucose.
The process then involves washing away the glucose and filtering out the cotton fibre fragments, leaving clean polyester behind.
“We still have some more work to do to characterize the polyester’s properties, but we think they will be very good because the conditions are so mild. We’re just adding enzymes that ignore the polyester,” Salmon added.
The study was published in the peer-reviewed journal ‘Resources, Environment and Sustainability’.