Cotton production often leads to competition with food crops for land and causes various environmental impacts. To reduce the demand for virgin cotton, many recycling technologies for cotton have been developed in recent years, including mechanical and chemical methods. Many life cycle assessment (LCA) studies have been published on cotton recycling processes, but their environmental benefit remains unclear because unified understanding on their assessment approach and challenges is lacking. Therefore, this review paper aims to provide a comprehensive literature survey on cotton recycling LCA through comparing the scope setting and assumptions among these studies, and observing the trends in this research. We also aim to offer references for future research agenda in this field. In this review, 19 articles were selected from the Web of Science and Scopus database for analysis based on the relevance. The conclusions of the LCA studies showed that using recycled cotton to replace virgin cotton can generally bring environmental benefits; for example, study report that climate change potential can be reduced by 13.6%. However, it is important to note that fair comparisons among the current LCA results are difficult because many studies use different assumptions related to LCA methods. For example, 27% of the studies set the system boundary at the fiber stage, 26% at the yarn stage, 37% at the fabric stage, 5% at the solution stage, and another 5% did not specify the form of the end product. Comparing studies with different system boundaries is impossible. To enable more rigorous comparisons of LCA results in the future, studies should consider using more consistent research methods and clearly state their assumptions in literature.
Hsu et al. (Thu,) studied this question.