Unlocking sustainable solutions: Harnessing recycled polyester from waste polyester/cotton blended textiles for membrane development

Blended cotton/polyester textiles, despite their popularity, present recycling challenges at the end of their lifecycle, contributing to environmental pollution. To address the urgent need for recycling, this study proposes a method to upcycle these textiles by separating polyester and cellulose with a natural deep eutectic solvent (NADES), creating value-added polyester membranes. Optimization of membrane fabrication involved varying dope concentrations, coagulation baths (ethanol, water), temperatures, and the effects of the pore-forming additive polyethylene glycol (PEG). The key finding is the significant role of ethanol and PEG synergy, which enables the production of tight ultrafiltration membranes from just 15% waste PET. The optimized membrane achieved a molecular weight cut-off of 2 kDa and a pure water flux of 23 L⋅m−2⋅h−1, surpassing typical commercial membranes. This advancement demonstrates a sustainable approach to reusing textile waste, with significant environmental benefits. •Successful membrane fabrication using recycled polyester from polycotton waste textiles.•Incorporating ethanol into coagulation bath led to more uniform and tighter membrane.•Fine-tuned casting parameters yield a membrane: 2 kDa cut-off, 11.5 L/m2/h/bar permeance.•Optimized membrane outperforms commercial ultrafiltration and polyester-bottle membranes.