Natural Deep Eutectic Solvent (NADES) Assisted Procedure to Separate Cotton and Polyester from Waste Blended Textile

Abstract Accumulation of large amounts of waste poly-cotton fabrics (WP-CFs) would lead to environmental challenges and depletion of resources. However, with a feasible fractionation technology the waste could be effectively utilized as pure fractions of cotton and polyester. For this purpose, this study aimed to separate the polyester and cotton into two different undegraded fractions from WP-CFs using Natural Deep Eutectic Solvent (NADES), which was composed of Choline chloride and Lactic acid (1:10 mol ratio); further, this work aims to test the suitability of milder process conditions to achieve effective separation. The separation process was carried out at different treatment temperatures, (90, 110, 120, and 140 °C), different solvent to solid (5:1, 10:1, and 20:1) ratios as well as different treatment durations (2, 4, 6, 8 h). Based on the results a bit larger scale separation was carried out at 110 °C for 3 h. The results showed excellent separation of cotton and polyester from waste poly-cotton fabric, and recovery of cotton (98%) and polyester (99%), respectively. Furthermore, the purity of cotton and polyester in the separated fractions was 98% and 99% respectively. The results demonstrate that the use of NADES in the treatment of the waste poly-cotton fabrics offers an attractive way to separate and recover pure polyester from waste blended textile, as well as partially degraded cotton that can be a potential low-cost source of cellulose in various industries. Furthermore, the recovered PET was undegraded, and we applied it as a polymer for filtration membrane fabrication.