An open-loop recycling for textile waste: high-value carbon materials from PET-PU industrial scraps

In the past few decades, global fiber consumption has been progressively increasing, leading to a higher amount of post-industrial and post-consumer fiber waste. Thus, an enormous amount of synthetic waste is generated, most of which is disposed of in landfills. Post-industrial waste is generated in the manufacturing process and, depending on the stage of manufacturing activities, it can be a single polymer or a complex multi-material system. Since a single polymer is easier to be recycled, a blend recycling process should be designed and projected. For companies, industrial blended scraps management is a very high challenge. The most used textile fiber is polyester (PET), with an estimated production of 26 million tons per year. The PET is often blended with other polymers, mainly with polyurethane (PU), to improve the elastic characteristics of the final products. The PET-PU separation is not an easily manageable process, especially for industrial scraps. For this reason, in this work, the obtainment of a high-value carbon material from PET-PU industrial waste was investigated. The PET-PU scraps were subjected to a pyrolysis treatment at 800°C leading to an 18% of carbon yield. The carbon was thoroughly characterized with several techniques (FTIR spectroscopy, surface area analysis, SEM) and a comparison with PET and PU carbons was also performed. Moreover, the adsorbing properties were evaluated in simulated-wastewater treatment by measuring their adsorption performances in removing two dyes: Orange II and Methylene Blue. These tests showed that the PET-PU-derived carbon is able to remove more than 60% of the two selected dyes. Thus, these preliminary results underline that the PET-PU blend can be easily recycled in an open-loop system in which the synthetic scraps are efficiently transformed into a new high- added value product.