A greener approach for physical separation of polycotton textile waste

Abstract

Most textile waste ends up in the landfill. Clearly, enhancing textile recycling is urgently needed. For circularity, efficient means for separating the constituents of the textile blends is crucial. Targeting the popular polycotton textile blend, a method was developed to physically separate cotton and PET (polyethylene terephthalate) from waste textiles. First, the waste polycotton textile was milled into smaller fibers to mitigate entanglement. Then, leveraging the relatively higher hydrophilicity of cotton, three liquids (namely, water, mineral oil, and ethanol) were mixed to form a two-phase liquid-liquid system, which induced the preferential segregation of cotton to the water-rich bottom liquid phase. Factors studied included liquid composition and milling method. The best-performing liquid mixture allowed for 84.7 % of the cotton and 85.5 % of the PET from the waste polycotton (WPC) sample to be recovered respectively from the bottom liquid phase (BLP) and top liquid phase (TLP). The separation effectiveness can be further enhanced if fiber entanglement issue can be mitigated. The recovery of about 99.9 % PET and 86.7 % cotton from a prepared mixture of pure cotton and pure PET textile wastes is a case in point, demonstrating the efficacy of the method that is fast, at ambient condition, and does not require extensive chemicals. While the interwoven design of cotton and PET in textiles confers benefits like comfort and strength, the resulting entanglement is detrimental for circularity. Synopsis: An eco-friendly yet rapid two-phase liquid-liquid system was developed for separating polycotton textile fibers, aimed at enhancing sustainability and circularity