The alarming rise of textile waste has been propelled by the rapid pace of fast fashion collections, resulting in substantial environmental consequences. Recent research reveals breakthrough advancements for transforming polycotton textile waste back to valuable materials, heralding significant progress toward sustainable recycling practices.
A team of researchers from Avantium has innovated a high-yield method for the sequential chemical recycling of cotton and polyester from mixed polycotton waste textiles. Utilizing 43 wt% hydrochloric acid for acid hydrolysis, researchers achieved a remarkable 75% molar yield of glucose from the cotton fraction within 24 hours at room temperature. This acid hydrolysis facilitates the separation of the glucose solution from the solid polyester residue.
The study indicates the scalability of this method, as trials conducted across varying sizes, from small laboratory experiments to 230 L pilot plant reactors, consistently yielded high recovery rates. "Using superconcentrated HCl on polycotton waste produces glucose solutions, conveniently separated from polyester residues, facilitating complete recycling," state the authors of the article.
Notably, this process addresses the historic challenges of recycling blended fabrics which usually leave both cotton and polyester components inadequately recovered. Research has previously shown recycling rates are staggeringly low, with less than 1% of textile waste being recycled. This novel approach not only enhances recycling efficiency but also plays a pivotal role in transitioning the textile sector toward a more circular and low-carbon economy.
Post acid hydrolysis, the residual polyester is processed through glycolysis to yield bis(2-hydroxyethyl) terephthalate (BHET) with 78% isolated yield and greater than 98% purity. This step furthers the recycling process, ensuring the polyester can be revitalized for potential reuse, paving the way for closed-loop recycling practices.
The research also highlighted the increasing role of regulatory frameworks such as Extended Producer Responsibility (EPR). "The introduction of the extended producer responsibility (EPR) has increased interest in recycling textile waste to the highest ever levels," the researchers assert. This newfound interest has led to innovations and investment within the textile recycling space, prompting companies to seek more sustainable pathways to manage end-of-life textiles.
Despite these advancements, challenges remain. The researchers noted variations between lab-scale results and pilot plant trials, indicating the complex variables involved at larger scales could influence efficiency and outcomes. For sustainability to be realized fully, continuous improvements and adaptations of the process are necessary.
A techno-economic analysis (TEA) performed as part of this research suggests the newly developed process has the potential to be the lowest-cost method for producing 2,5-furandicarboxylic acid (FDCA), which is a key monomer for next-generation bioplastics.
The production costs for bis(2-hydroxyethyl) terephthalate (BHET) range from €1000 to €5000 per ton, depending on the scale of polycotton input, significantly lower than traditional methods using wood or fructose. This indicates not only feasibility but also the possibility of commercial viability and wider applications of this technology.
Given the innovative nature of this research, it signals a pivotal shift toward more effective recycling strategies for blended textiles, driving forward the necessary changes to make the textile industry more sustainable. Following these findings, the research opens avenues for future investigations to optimize the hydrolysis and glycolysis processes even more, solidifying the pathway toward comprehensive textile recycling solutions.