Dyeout: biobased solvent extraction for mechanical textile recycling and dye recovery

Overview

Textile waste is one of the fastest-growing components of municipal solid waste, driven largely by fast fashion cycles. A major barrier to mechanical textile recycling is the high loading of dye molecules embedded in fibers; when dyed fibers are blended during recycling, the resulting discoloration and fiber degradation reduce the quality and value of downstream products. DyeOut addresses this challenge by selectively extracting dyes from waste textiles before they enter the recycling stream, producing cleaner, higher-value dye-free fibers while also recovering dyes that can be reintroduced into the textile supply chain.

Technical specifications

• Biobased solvent extraction: A biobased solvent selectively removes colorants from textile fibers in a continuous packed-bed column process.
• Demonstrated performance: Achieves greater than 85% dye removal from both polyethylene terephthalate (PET) and cotton-based textiles, which together represent approximately 83% of all textile materials.
• Crossflow reactor system: Shredded textiles are packed into a column through which the biobased solvent flows continuously, enabling efficient and scalable extraction.
• Dye and solvent recovery: Membrane filtration recovers up to 93% of dyes from the extracted solution while purifying the solvent for reuse in a closed-loop configuration.
• Versatile feedstock handling: Validated on shredded textile inputs, with planned validation on whole garments at larger scales.
• IP status: Provisional patent filed (PROV/22-106), developed in collaboration with Patagonia.

Technology readiness level

DyeOut has been demonstrated at the 100 g laboratory scale using a crossflow reactor with both PET and cotton textile feedstocks, confirming high dye removal efficiency and effective membrane-based dye and solvent recovery. Current and planned validation efforts include scaling the process to a 100 L reactor operating on greater than 1 kg of waste PET textiles, integrating membrane separations for greater than 95% dye recovery, developing a commercial-scale process flow diagram using process simulation software, and completing technoeconomic and life cycle analyses to determine minimum selling prices and environmental impact. These activities position DyeOut to advance from laboratory-scale validation toward commercial-scale readiness.