Researchers have developed a method that converts cotton into sugar that in turn can be turned into spandex, nylon, or ethanol.
Most discarded materials go straight into an incinerator or end up in landfills. Fabrics with strong fibers can be reused. However, much of the fabric that is discarded has fibers that are too short for re-use and sooner or later, all cotton fibers become too short for the process known as fiber regeneration.
The team’s method breaks down the plant fiber in cotton — the cellulose — into smaller components. Rather than using micro-organisms or enzymes, the process involves soaking the fabrics in sulphuric acid. The result is a clear, dark, amber-colored sugar solution.
Glucose is a very flexible molecule and has many potential uses. The new method would produce chemicals that in turn could become various types of textiles including spandex and nylon. An alternative use could be to produce ethanol.
From a normal sheet, the method extracts five liters of sugar solution, with each liter containing the equivalent of 33 sugar cubes. That liquid, however, could not be turned into a soft drink, as it also contains corrosive sulphuric acid. One of the challenges is to overcome the complex structure of cotton cellulose.
What makes cotton unique is that its cellulose has a high crystallinity, making it difficult to break down the chemicals and reuse the components. In addition, there are a lot of surface treatment substances, dyes, and other pollutants that must be removed.
The concept of hydrolizing pure cotton is nothing new; it was discovered in the 1800s. The difficulty has been to make the process effective, economically viable, and attractive.
Once the recipe formulation is complete, it will be both relatively simple and cheap to use. For the process to become a reality, the logistics must work. There is currently no established way of managing and sorting various textiles that are not sent to ordinary clothing donation points.
For more information, contact Edvin Ruuth, Department of Chemical Engineering, at