Recycling of dope-dyed cellulosic waste using Lyocell-based processes

The textile industry faces several significant challenges, including low recycling rates, the use of harmful substances, and its contribution to chemical pollution. Currently, most post-consumer textiles end up in landfills or incineration. For this reason, it is crucial to implement sustainable practices for recycling textile waste.

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The BioSusTex research project focuses on sustainable and resource-efficient recycling of cellulosic textile waste. During the fiber-to-fiber recycling process, initial dope-dyed fibers are recycled while maintaining their color and mechanical properties. This task aims to increase the recycling rates of cellulosic textile waste and to move towards a more circular economy of textiles. This is an essential step in reducing the environmental impact of textile production.

The objective of this task in the BioSustex project is to optimize an efficient recycling process for dope-dyed cellulosic waste using Lyocell-based recycling techniques. The mechanical and color properties of the obtained fibers are compared to the initial material.

Initial dope-dyed viscose fibers (left) & recycled fibers using Lyocell-based process (right) credits to Biopolymer Chemistry and Engineering Group at Aalto University.

For Lyocell-based processes, the recycling process can be started without any initial pretreatment. The initial fibers were mechanically ground into smaller particles to increase their dissolution in the ionic liquid that is used in the process. The solvents are recyclable and non-toxic, which makes the process more sustainable compared to conventional chemical recycling methods. Also, the solvents can be recovered, this makes it a closed-loop system. The obtained fibers were stronger with similar color properties to the initial fibers, which introduced this process as an innovative recycling process because it improves the mechanical properties of the fibers and preserves the color, as shown in the image below.

The advantages of this technique lie in its ability to reduce the need for further dyeing of textiles, as textile coloration is a crucial contributor to water pollution. In addition, the need for new textile production can be diminished. The results of this research indicate a promising solution for recycling dope-dyed cellulosic fibers using Lyocell-based processes and achieving sustainable textile production.

Please contact Dr. Ali Tarhini, Postdoctoral Researcher at Biopolymer Chemistry and Engineering Group at Aalto University for future information about this topic (ali.tarhini@aalto.fi).