Optimising chemo-enzymatic separation of polyester cellulose blends
K. Steiner, Viktoria Leitner, Franz Zeppetzauer, Doris Ostner-Kaineder, Christoph Burgstaller, Harald Rennhofer, A. Bartl, Doris Ribitsch, Georg M. Guebitz
Abstract
The study demonstrates the potential of enzymatic hydrolysis and alkaline pretreatment for sustainable blended textile recycling. The target is complete cellulose removal while preserving the polyester integrity for recovery. Interactions of sodium hydroxide concentration (10 %–30 %), urea concentration (0 %–12 %), and temperature (-20 °C–50 °C) were investigated during pretreatment using a design of experiments. Analysis revealed a bimodal pattern in polyester mass loss, with one peak at lower concentrations and temperatures, and a more prominent peak at higher concentrations and temperatures. Cellulose hydrolysis also occurred under high NaOH concentrations and elevated temperatures (50 °C, 30 % NaOH, 0 % urea). Optimal conditions, preserving polyester integrity while achieving complete cellulose elimination, were identified at temperatures between 6.2 °C and 13.3 °C, with NaOH concentrations of 20.7 %–26.6 % (0 % urea) or 13.9 % NaOH and 12 % urea. These findings pave the way for a greener, more efficient textile recycling, advancing the circularity for textiles.