Beyond Polycotton: How Other Fibers Affect the HCl-Based Polycotton Recycling Process

With the increasing generation of textile waste, efficient chemical recycling methods are urgently needed. This study evaluates a hydrochloric acid-based process for recycling polycotton textiles (polyester/cotton blends), in which cotton is selectively hydrolyzed and converted into 5-(chloromethyl)furfural (CMF), while polyester is recovered. The impact of common non-polycotton fiber contaminants on process performance and product quality was systematically assessed. Cellulose-based fibers did not hinder the process and are suitable for CMF production, while most synthetic fibers were effectively removed without affecting the CMF yield. In contrast, animal fibers reduced the CMF yield and complicated acid recovery, indicating they should be avoided in the feedstocks. Additionally, polyacrylonitrile and wool persisted in the solid fraction, contaminating the recovered polyester and lowering its value. To improve process robustness and product quality, intermediate filtration and extended hydrolysis time are recommended. These findings highlight critical feedstock requirements and operational adjustments for scalable polycotton recycling.