Avaliação da pirólise no manejo de resíduos têxteis mistos

Abstract

Textile industry, with its significant social and economic contribution, faces challenges in effectively managing its waste, especially due to the lack of signifacnt data on its disposal and to the fact that textile waste is the leading cause of microplastic pollution in the ocean. This study aims to investigate pyrolysis of two types of mixed cotton-polyester textile fabrics, 80% cotton/20%polyester and 65%cotton/35%polyester, to analyze pyrolysis efficiency in textile waste management. The fabrics were characterized using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). Two pyrolysis processes were conducted: the first was carried out in a TGA furnace (800°C) to assess mass reduction and microscopic analysis for microplastic detection. The second was performed in a fixed-bed furnace (450°C – 485°C) to potentially enhance the generated residue’s value by chemically activating it with zinc chloride (ZnCl2) for analysis in methylene blue adsorption tests. Both fabrics exhibited similar weaves in SEM. In TGA, the fabrics displayed similar degradation temperatures, ranging between 422°C and 425°C. FTIR analysis revealed functional groups confirming the presence of both cotton and polyester in their composition. The results of the first pyrolysis showed a reduction of over 84% in mass for both fabrics, with microplastic detection in the generated residues from all samples analyzed, projecting a generation of up to 25.77 million microplastics per kilogram of generated waste. In the second pyrolysis, it was observed that, under the conducted analyses and conditions, the generated residues were not suitable for use as activated carbons for adsorbing contaminants in aqueous solutions. It is noteworthy that pyrolysis is an effective alternative for managing mixed textile waste, as it exhibits a high degree of mass reduction in these residues. Therefore, there is a need for proper disposal due to the high generation of microplastics observed.