Finland’s textile research and development institute VTT has collaborated with the Aalto University to examine the compatibility of different dyeing methods and color removal. The study involves using different methods to dye cotton materials and then decolorizing the textiles. The dye and the dyeing method used by these two institutes proved to be decisive for color removal, meaning it is only possible to effectively reuse waste textile if information is available on the dyeing methods used. They have also published a paper on their study, titled “Color Management in Circular Economy: Decolorization of cotton waste” which has won the Paper Award in the 2020 Emerald Literati Awards.

The paper notes on an industrial scale, dyeing and decolorizing textile fibers have a high environmental impact. The process consumes chemicals, energy and water, and generates wastewater. During this process, the fibers can also be purified from other harmful chemicals, avoiding their transfer to recycled fiber products. All this opens up new opportunities for reuse, says Marjo Maattanen, Principal Scientist, VTT.

On the other hand, a recycled look is desirable feature for products made from waste textile. The process does not need to separate textiles dyed with different methods and remove the dye, the paper noted. It can identify and collect separately the textiles dyed with a particular method, it added. Professor Kirsi Niinimäki said, using textile waste requires information on its fibers, dyes and dyeing methods, and chemicals. This information needs to be collected at the manufacturing stage and stored alongside the textile fiber until it reaches the end product, he added.