Defence of doctoral thesis: Edvin Bågenholm-Ruuth – Recycling Cellulosic Textile Waste: Combining Closed- and Open-Loop Recycling in a Cascade Chain to Maximise Value Recovery

Abstract

The environmental impact of the textile industry is immense, and textile waste is accumulating globally at an unprecedented rate. To address this issue, innovative technologies for handling, sorting, and recycling textile waste are crucial. This thesis presents a comprehensive study on the recycling of cellulosic textile waste through both closed-loop and open-loop pathways.
Closed-loop recycling is demonstrated using hydrated zinc chloride to dissolve and regenerate cellulosic textiles into recycled fibres, either via dissolving pulp or through direct spinning from solution, with process conditions enabling precise control of intrinsic viscosity and cellulose structure. Open-loop recycling is achieved by further valorising the dissolving pulp or by hydrolysing the waste, chemically or enzymatically, depending on the composition of the waste.
Further valorisation is demonstrated through lactic acid fermentation using viscose hydrolysate as a substrate, and alternative applications for the non-hydrolysable fraction are also presented. Finally, all developed processes are integrated into a cascade chain, forming a cohesive strategy for recycling cellulosic textile waste. This approach ensures maximal value recovery and enables each waste fraction to be directed to the most suitable recycling pathway.