Young chemists from the University of Copenhagen have made a significant advancement in the recycling of polyester, which has the potential to transform the sustainability of the textile sector. Recycling within the business has long been difficult due to the difficulty of separating plastic and cotton in composite fabric.
“A new way to manage blended materials like polyester/cotton is urgently needed by the textile industry. There are currently relatively few practical ways to recycle both cotton and plastic; most often, it’s either-or. However, utilizing our recently developed method, we can recover cotton on a scale of hundreds of grams while also depolymerizing polyester into its monomers in a very simple and sustainable manner. The lead author of the work and postdoc Yang Yang of the Jiwoong Lee group at the University of Copenhagen’s Department of Chemistry said that this traceless catalytic approach “could be the game-changer.”
However, a creative strategy avoids this issue without the use of any specialized equipment. According to an article posted on the University of Copenhagen’s internet page, the solution was discovered using warmth, a typical, non-hazardous solvent, and a common home ingredient.
“A polyester dress, for instance, may be broken up into small pieces and put in a container. Add a small amount of a gentle solvent next, followed by hartshorn salt—often used as a leavener in baked goods. After heating everything to 160°C for 24 hours, we proceed. As a result, layers of plastic and cotton fibers have formed in the liquid. Shriaya Sharma, a doctorate student in the Jiwoong Lee group in the Department of Chemistry and a co-author of the work, described the procedure as being straightforward and affordable.
Ammonium bicarbonate, often known as hartshorn salt, is used in the method; it decomposes into ammonia, CO2, and water. Ammonia and CO2 combine to create a specialized reaction known as selective depolymerization, which breaks down polyester while protecting cotton fibers from damage. Even while ammonia by itself can be dangerous, when coupled with CO2, it becomes secure and environmentally benign. The cotton fibers are kept in perfect condition by the mild nature of these compounds.
This study team has previously demonstrated how CO2 may function as a catalyst to dissolve several polymers, including nylon, with no residue. They looked into the possibility of hartshorn salt because of this earlier research. The findings from this easy technique thrilled the researchers.
We were initially thrilled to see it perform so well on PET bottles alone. Then, we were overjoyed to learn that it also worked on polyester cloth. It was beyond words. The fact that it was so straightforward to execute was almost too wonderful to be true, according to Ph.D. student and study co-author Carlo Di Bernardo.
Although this method has only been tested in the lab so far, its potential for wider applications is clear. To investigate the procedure’s potential at the industrial level, scientists are actively interacting with enterprises.
