Hochschule Niederrhein R&D

 Chemical and Biochemical Recycling of Post-Consumer Textile Waste 

Introduction: The rise of fast fashion has drastically increased textile waste, much of which ends up landfilled or incinerated, harming the environment. The mixed composition of mate- rials, such as cotton and polyester, complicates recycling due to limited sustainable technologies. This initiative seeks to develop chemical and biochemical methods like hydrothermal liquefaction and enzymatic hydrolysis to recover valuable products, ensuring minimal environmental impact through lifecycle assessments and scalable pilot trials to support a circular economy. Additionally, this approach aims to address the growing demand for sustainable solutions in the textile industry, reducing dependency on virgin raw materials. By integrating innovative recycling processes, the project aspires to mitigate resource depletion while con- tributing to global sustainability goals. Furthermore, it underscores the importance of fostering industrial collaborations to ensure practical implementation and long-term viability of these recycling technologies [1]–[5].

Research Goal: Develop efficient recycling methods to recover valuable components from mixed textiles using chemical and enzymatic processes while optimizing parameters for scalable, zero-waste recycling with minimal environmental impact.

Means and Methods:

Pre-treatment of Textile Waste: A dual-stage pre-treatment process will enhance recycling efficiency. Chemical pre-treatment with mild alkaline or solvent solutions will remove dyes and coatings [1], [3]. Biochemical pre-treatment using enzymes like cellulase and lipase will break down fibers and improve component accessibility [4], ensuring better feedstock preparation with reduced energy and chemical use.

Chemical Recycling Processes: The chemical recycling stage will use Hydrothermal Liquefaction (HTL) to break down polyester fibers into monomersterephthalic acid (TPA) and ethylene glycol—at optimized water conditions (300–350°C) [1]. Alkali catalysts like KOH will enhance ester bond cleavage. GC-MS and FTIR will validate the recovered products [5]. 

Biochemical Recycling Processes: Enzymatic hydrolysis will target cellulose-rich textiles using PETase, MHETase, and cellulase, optimized for temperature, pH, and enzyme concentration via Response Surface Methodology (RSM). This process will produce glucose and cellulose derivatives for bio-based materials or bioenergy [3], [4]. Integration with chemical recycling will valorize residual compounds, forming a hybrid recycling framework [5]. 

Product Recovery and Valorization: Post-recycling, target product recovery will include acid-base extraction to isolate TPA and separate it from char-like residues, distillation to purify ethylene glycol and bio-oil fractions, and crystallization and filtration for glucose recovery. By- products such as biochar and residual dyes will be explored for applications in soil amendment and construction materials [2], [3].

Lifecycle Assessment (LCA) and Environmental Impact Evaluation: A lifecycle assessment will evaluate the sustainability of the proposed recycling methods. The LCA will consider raw material inputs, energy consumption, emissions, and end-of-life disposal. Special focus will be placed on the biodegradability of by-products and the eco-toxicological impact of the recycling processes [1], [2]. The goal is to quantify environmental benefits while ensuring compliance with global sustainability goals [3].

Scale-Up and Industry Collaboration: Pilot-scale trials will test the feasibility of integrating the proposed methods into existing recycling infrastructures. Industry collaborations will assess scalability, economic viability, and market acceptance of the recycling processes. The approach will include cost-benefit analysis and technical validation to encourage adoption by textile manufacturers [2], [5].

References:

1. [1]  A. Matayeva and P. Biller, “Hydrothermal liquefaction of post-consumer mixed textile waste for recovery of bio-oil and terephthalic acid,” Resources, Conservation and Re- cycling, vol. 185, p. 106 502, 2022.

2. [2]  M. A. Shahid, M. T. Hossain, M. A. Habib, et al., “Prospects and challenges of recycling and reusing post-consumer garments: A review,” Cleaner Engineering and Technology, vol. 19, p. 100 744, 2024.

3. [3]  I. Wojnowska-Baryła, K. Bernat, and M. Zaborowska, “Strategies of recovery and organic recycling used in textile waste management,” International journal of environmental re- search and public health, vol. 19, no. 10, p. 5859, 2022.

4. [4]  R. B. Baloyi, O. J. Gbadeyan, B. Sithole, and V. Chunilall, “Recent advances in recycling technologies for waste textile fabrics: A review,” Textile Research Journal, vol. 94, no. 3-4, pp. 508–529, 2024.

5. [5]  Y. Arafat and A. J. Uddin, “Recycled fibers from pre-and post-consumer textile waste as blend constituents in manufacturing 100% cotton yarns in ring spinning: A sustainable and eco-friendly approach,” Heliyon, vol. 8, no. 11, 2022.