Textile waste refinery for the production of recycled plastic, cellulose and dye

服装纺织品是塑料的主要使用者，其中塑料成分经常与棉花和羊毛等天然纤维结合。2017年，全球共生产了4.38亿吨塑料，其中6200万吨用于纺织行业（塑料包装使用量为1.58亿吨）。因此，纺织废物中的塑料是塑料废物问题的主要但隐藏的贡献者。在英国，每年产生250万吨塑料包装和超过100万吨纺织废物。虽然塑料包装已经引起了全球的关注和关注一段时间，但纺织废物只是最近才变得突出，部分原因是将塑料与天然纤维和其他成分分离使得回收纺织废物成为一项具有挑战性的任务。2016年英国的一项调查显示，55%的纺织废物被填埋，26%被焚烧，16%被回收/再利用，其中不到1%的纺织废物被用于生产新服装的材料。除了旧衣服经慈善机构回收或再用外，纺织业所用的大部分塑料都没有循环再造，造成塑料污染及原料消耗。如果能将纺织废料中的塑料成分（主要是聚酯）与棉花、染料及其他成分分离，便可将其循环再造为再生纤维，方法与回收塑料瓶制造纺织品的方法相同。现有的机械回收技术可以回收由单一聚合物组成的纺织品废物，但无法处理复杂的纺织品，如涤棉服装（聚酯和棉花的混合物）。化学回收方法将纺织纤维分解成它们的结构单元，然后通过适当的纺丝技术合成新的聚合物和新的纤维。但化学品回收是能源密集型的，（由纤维素形成）和羊毛（蛋白质纤维），被降解到不能用来产生新纤维的程度，因此失去了它们的内在价值。哈德斯菲尔德大学的研究人员最近开发了一种酶辅助的纺织废物增值过程，该过程将纤维素分解为葡萄糖用于生物燃料发酵，允许回收剩余的聚酯。该项目将对酶法进行改进，使纤维素仅部分分解，从而使其与涤棉中的聚酯分离，这样两种成分都可以回收并重新纺成新的纺织纤维。该项目还将采用离子液体萃取法从塑料中分离纤维素，单独或结合酶处理。离子液体可以溶解纤维素，但常用的离子液体价格昂贵，限制了其商业应用。伦敦帝国理工学院的研究人员率先开发了使用便宜得多的离子液体的更可持续和更具成本效益的离子液体提取工艺。用于可持续纤维素生产的ionoSolv工艺被《科学美国人》选为2019年十大新兴技术之一，目前正在由Lixea有限公司（www.lixea.co）在瑞典一家耗资400万英镑的定制中试工厂进行商业化，用于废物生物质的分级。在这个项目中，ionoSolv技术将被应用于回收天然纤维素纤维和废旧纺织品中的染料，以适合在新的纺织产品中重复使用的形式。回收的聚酯和纤维素将在哈德斯菲尔德大学的纺织技术研究中心重新纺成纤维。再生纤维将被工业合作伙伴用于证明其适用于制造新的纺织产品。将评估新工艺的经济、社会和环境影响，以确定其对整个价值链的利益相关者--回收商、制造业、零售商、消费者和整个社会--的好处。

Textiles for clothing are a major user of plastics, in which the plastic component is frequently combined with natural fibres such as cotton and wool. Globally, 438 million tonnes of plastic were produced in 2017, of which 62 M tonnes were used in the textile industry (compared with 158 M tonnes used in plastic packaging). Plastics in textile waste are thus a major, but hidden, contributor to the plastic waste issue. In the UK, 2.5 M tonnes of plastic packaging and >1 M tonnes of textile waste are generated annually.While plastic packaging has attracted attention and concern worldwide for some time, textile waste has only become prominent recently, in part because separating the plastic from the natural fibres and other components makes recycling textile waste a challenging task. A 2016 UK survey showed that textile waste goes to landfills 55%, incineration 26% and recycling/reusing 16%, with <1% textile waste used to generate material to be used for producing new clothing. Apart from old clothes recycled or reused via charity organisations, the majority of the plastic used in the textile industry is not recycled, contributing to plastic pollution and depletion of raw materials.If the plastic component (mainly polyester) can be separated from cotton, dye and other components in the textile waste, it can be recycled into reclaimed fibres using the same method for recycling plastic bottles into textile products. Existing mechanical recycling technology can recycle textile waste composed of a single polymer, but is not able to treat complex textiles such as polycotton garments (a mixture of polyester and cotton). Chemical recycling methods break down the textile fibres into their building blocks and then synthesise new polymers and subsequently new fibres via appropriate spinning techniques. But chemical recycling is energy intensive and natural fibres, such as cotton (formed of cellulose) and wool (protein fibre), are degraded to a point that they cannot be used to generate new fibre, therefore losing their intrinsic value.Researchers at the University of Huddersfield have recently developed an enzyme-assisted textile waste valorisation process that breaks down cellulose into glucose for biofuel fermentations, allowing recycling of the remaining polyester. The proposed project will modify this enzymatic approach to only partially break down cellulose to enable its separation from the polyester in polycotton, such that both components can be recovered and re-spun into new textile fibres.The project will also apply ionic liquid extraction for the separation of cellulose from plastics, separately and in combination with enzyme processing. Ionic liquids can dissolve cellulose, but the high price of commonly used ionic liquids have limited their commercial application. Researchers at Imperial College London have pioneered the development of more sustainable and cost effective ionic liquid extraction processes using much cheaper ionic liquids. The ionoSolv process for sustainable cellulose production was selected by Scientific American as one of the Top Ten Emerging Technologies of 2019 and is currently being commercialised for the fractionation of waste biomass by Lixea Ltd. (www.lixea.co) at a £4 million bespoke pilot plant in Sweden. In this project, ionoSolv technology will be applied to recover both the natural cellulose fibres and the dyes from waste textiles, in forms suitable for reuse in new textile products.The recycled polyester and cellulose will be re-spun into fibre at the Technical Textile Research Centre at the University of Huddersfield. The regenerated fibre will then be used by the industrial partner to demonstrate its suitability for making new textile products. The economic, social and environmental impacts of the novel process will be assessed for its benefits to stakeholders throughout the value chain - recyclers, manufacturing industries, retailers, consumers and society as a whole.