Polyester, the second most used textile in the world, poses a threat to the environment as it is difficult for industry to separate and recycle. A team of chemistry researchers at the University of Copenhagen in Denmark has invented a green solution that uses only household ingredients. The research was published in the latest issue of the journal ACS Sustainable Chemistry and Engineering.
An astonishing 60 million tons of polyester fiber is produced annually. However, only 15% of polyester is recycled, and the rest ends up in landfill or incineration, causing more carbon emissions and harming the climate and the environment.
The new technique developed at the University of Copenhagen requires no special equipment, just a heating process, non-toxic solvents and common household ingredients. The researchers cut a polyester dress into small pieces and placed them in a container. Then, add a mild solvent and antler salt (a leavening agent in baked goods), heat it to 160°C and let it sit for 24 hours. The result is a liquid in which plastic and cotton fibers settle in separate layers.
During this process, the antler salt is broken down into ammonia, carbon dioxide and water. The combination of ammonia and carbon dioxide acts as a catalyst, triggering a selective depolymerization reaction that breaks down the polyester while retaining the cotton fibers. While ammonia is toxic when used alone, when combined with carbon dioxide it becomes environmentally friendly and safe. Because of the mild nature of the chemicals involved, the cotton fibers remain intact.