In the recent decennia, ingrained consumption patterns and the rising of fast fashion have caused the fashion industry to become one of the most polluting industries on earth. The immense global demand for new clothing in the fashion industry requires an equally large production of raw materials. In the case of renewable raw materials such as cotton, no fossil-fuel-derived resources are required such as for synthetic fibers. However, the production of cotton is a water- and pesticide intensive process, causing deforestation for agricultural land for cotton cultivation, and the further dyeing and finishing processes to obtain yarns and ready-to-wear clothes form the cotton plants also consist of chemical processes with significant environmental impact. Furthermore, quick turn-over of textile-products in the current fast-fashion mindset causes immense amounts of waste textiles ending up in landfill due to circular waste management being behind on the large production speed of the materials.

In other words, the discarded textile-products mostly end up in large mountains of waste – also called ‘landfills’ – and strand there at their linear end-of-life stage, waiting to get slowly broken down again in case of natural fibers, or end up as degraded microplastics in soil and water-streams in case of synthetic fibers after considerable time of exposure by wind and weather. Therefore, not only does this discarding of waste-textiles in landfills lead to immediate pollution by the degraded textile-material, but also to obstructing any possibility for circular reuse of the raw materials, causing a further increase of the request for production of new raw materials.

From this perspective, it is clear that more textile recycling is needed. However, chemicals such as dyes and finishes added to the textiles during processing impede efficient textile recycling by possibly reducing the quality of the recycled fibers. Therefore, textiles go through a discoloring pre-treatment before the actual mechanical or chemical recycling step. Since cotton is most often dyed with reactive dyes, binding directly to the textile, current industrial color-stripping treatments for cotton textiles are often based on harsh processes requiring high amounts of toxic and textile-damaging chemicals, energy, and water. Therefore, this pre-treatment for textile recycling often comes with its own significant environmental impact.

This insight formed the basis for the research-idea behind this article; the investigation of an alternative process for the discoloration of cotton waste prior to textile recycling. Literature shows that the use of the Fenton-process (an iron-catalyzed mechanism generating the highly reactive hydroxyl-radicals, which attack the organic substance such as dyes) has been shown to be a versatile tool in the degradation of organic pollutants for waste-water treatments, for example in the context of discoloration of wastewater. However, the use of Fenton for discoloration of waste textile seemed to be a new approach. Therefore, this article aimed to investigate the feasibility of the Fenton-process as a discoloring pre-treatment for textile recycling.

With reduced requirements of chemicals, energy and duration of the treatment, Fenton has been shown to be feasible for the discoloring pre-treatment of cotton waste. However, this treatment also caused some degradation of the cotton itself. This degradation might prove to be useful for mechanical recycling, since it enhances the first step of shredding of the material. However, if after shredding the remaining fibers become too short, the quality of the recycled fibers might also decrease. Therefore, more research towards the impact of this pre-treatment on the actual recycling step would be an interesting follow up. For that reason, we hope that this initial feasibility study will inspire following research on the optimization of the Fenton-discoloration of waste cotton, and further on also investigation of the impact of this treatment on cotton recycling process and the quality of the recycled fibers. In time, this more environmental-friendly discoloration process might become a commercially competitive process, useable for industrial scale efficient recycling of waste cotton.