Researchers from Japan’s University of Fukui have optimised a decolorisation process, known as supercritical fluid dyeing which effectively penetrates fabric fibres to remove the dyes with minimal environmental impact. The extracted dyes can be reused, and the fabrics be redyed.
THE PROCESS: The researchers first created supercritical carbon dioxide (CO2) fluid inside a specialised heated and pressurised vessel and mixed it with a decolorising agent before adding it to the dyed fabric.
- The idea was that by adding a decolorising agent with a solubility parameter between those of the dye and the fabric, efficient decolorisation could be achieved.
- Using these techniques, an astounding decolorisation rate of over 90–100% was achieved.
- Notably, this strategy was found to be effective for polyester fabrics.
- The processing liquids, extracted dyes, and decolorising agents can also be repurposed and reused effectively.
THE TEAM: Led by Professor Kazumasa Hirogaki and Visiting Professor Teruo Hori, the study builds on outcomes from the NEDO Feasibility Study Program/Feasibility Study Program on New Technology and was further developed under the JST COI-NEXT Program on open innovation platforms for industry-academia co-creation (COI-NEXT).
- The researchers are actively seeking to commercialise this technology with hopes of transforming the "make, use, and dispose" model of the textiles industry into a truly circular and sustainable "make, use, and reuse" model.
