Selective solvent extraction and quantification of synthetic microfibers in textile laundry wastewater using pyrolysis-gas chromatography/mass spectrometry

This paper reports a new qualification and quantification method for synthetic microfibers (MFs), polyethylene terephthalate (PET), nylon-6 (N-6), and polyacrylonitrile (PAN), emitted from textiles during the laundering process by applying a sequential process involving the filtration of laundry wastewater, solvent extraction with hexafluoroisopropanol (HFIP), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). After filtering the textile laundry wastewater, selective sampling of synthetic MFs excluding non-target matrices and natural fibers was achieved by extracting the filtered samples with HFIP. MF recovery for HFIP extraction by Py-GC/MS analysis was 91.4 %, 98.5 %, and 98.8 % for PET, N-6, and PAN, respectively. The calibration curves obtained from Py-GC/MS analysis for PET, N-6, and PAN in the weight range between 1 and 50 μg showed good linearity (R² > 0.994). The detection and quantification limits were lower than 0.2 μg and 0.6 μg for all polymers. The quantification results for the MFs extracted from the textile made from a single filer indicated that PET, N-6, and PAN textile produced 481, 111, and 329 mg of MFs/kg textile, respectively. Compared to the single textile (PET), the blended textiles produced larger amounts of MPs, 961 mg/kg for PET/cotton and 680 mg/kg for PET/wool blended textiles, suggesting the easier formation of MFs from blended textiles during textile laundering.