A research team at Lund University in Sweden has successfully transformed waste cotton sheets into new viscose materials. This not only gives new value to waste textiles, but also relieves the pressure on garbage disposal.
Globally, used textiles are often left in landfills or incinerated, but in Sweden they are often used as fuel for district heating. The textile industry has been working hard to carry out extensive research and development efforts to give used clothing and textiles a more meaningful destination.
The planet’s need for recycled textiles is urgent. The process of growing cotton and other textile raw materials consumes a lot of energy, water and land. Therefore, the reuse of waste textiles not only contributes to environmental protection, but also meets the requirements of sustainable development. Of course, we still face many challenges in advancing this process, but we firmly believe that through continuous efforts and innovation, we will be able to overcome these difficulties and contribute to the sustainable development of the earth.
The core component of plant fiber - cellulose chain, has a complex and long structure. Cotton textiles also undergo intensive processing with dyes, protectants and other chemicals during their production. Edvin Bågenholm-Ruuth, a doctoral student in chemical engineering at Lund University, further points out: “In addition, there are also various stubborn dirt that adhere to the skin in the form of skin flakes and fat.”
Now, his research team has successfully developed an innovative method that can effectively loosen and convert complex cotton fibers into viscose fibers. Viscose, also known as rayon, is a common material used in the manufacture of clothing such as tops, skirts and dresses. Its raw material is mainly cellulose, in most cases derived from wood.
Although viscose produced from old cotton fibers already exists, a high proportion of “virgin” fibers is usually required to create a high-quality product. The team's research is precisely to break through this limitation, achieve efficient utilization of waste cotton fibers, and contribute to environmental protection and sustainable development.
"We are using white textiles, but if you are using dyed old clothes, you may need to add a decolorization stage. It would be better if you can do this while avoiding traditional bleaching, which is a very A resource-intensive process that has a considerable impact on the environment."
Late last year, researchers released a study detailing this innovative process. They plan to build a pilot plant somewhere in Europe to further advance the practical application of this technology. According to a press release issued by the university, the method performed well in spinning tests on viscose threads and achieved satisfactory results.
This method is attracting attention first of all because of its significant cost-effectiveness. It only requires a common and simple salt - zinc chloride - that dissolves easily in water. In addition, compared with the standard process, the proportion of the toxic substance carbon disulfide required by this method is significantly reduced, which undoubtedly opens up new avenues for environmentally friendly production. Bagenholm-Ruuth said that although this process needs further refinement and optimization, it is currently able to produce high-quality viscose fibers.
He also mentioned: "Currently we are mainly using white textiles for experiments, but if dyed old clothes are used as raw materials in the future, it may be necessary to add a decolorization stage. We are working hard to study how to achieve this without using traditional bleaching processes. "This is a goal, because the bleaching process not only consumes a lot of resources, but also has a significant impact on the environment." By continuously optimizing this process, it is expected to make an important contribution to the sustainable development of the textile industry and environmental protection.
Putting waste textiles in a zinc chloride solution, they are completely transformed into a viscous state in just one hour. Then, by adding an appropriate amount of water, a fluffy white substance gradually precipitates out of the solution, which the researchers call "dissolving slurry." This dissolving pulp can be easily filtered from the liquid and has the potential to replace the wood pulp currently used in the viscose process.
In the next stage, after careful treatment with various chemicals including carbon disulfide, the dissolving slurry can be smoothly dissolved in sodium hydroxide. Then, through processes such as dissolution and spinning, the pulp is finally transformed into viscose fiber. This process not only enables the reuse of waste textiles, but also reduces dependence on natural resources such as wood, opening up a new path for the sustainable development of the textile industry.