Pyrolysis Process of Mixed Microplastics Using TG-FTIR and TED-GC-MS

Abstract

Microplastics have become a ubiquitous contaminant in the environment. The present study focuses on the identification, characterization, and quantification techniques for tracking microplastics. Due to their unique compositional structure, unambiguous identification of individual polymers in various plastic samples, usually comprised of mixtures of individual polymers, remains a challenge. Therefore, there is limited research on the pyrolysis characterization of mixed samples. In this study, two analytical methods, TG-FTIR and TED-GC-MS combined with thermogravimetric analysis were used to evaluate the thermal-degradation process of individual and mixed samples of polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). The primary interaction was the volatilization of terephthalic acid bound to chlorine molecules. The reduction of vinyl-ester functional groups and aromatic hydrocarbon intermediates related to olefin branching was confirmed. Char formation was increased, due to aromatic compounds from PET and PVC. All of the polymers used in the study may be underestimated in quantity, due to combined volatilizations during pyrolysis. TG-FTIR and TED-GC-MS showed forceful advantages in identifying mixed microplastics through different discrimination mechanisms. The study provides deep insight into pyrolysis behaviors and the interactions of mixed polymers, and the obtained results can help better comprehend the complex pyrolysis process.

Microplastic Analysis in Soil Using Ultra-High-Resolution UV–Vis–NIR Spectroscopy and Chemometric Modeling

“…The limitations of both techniques make it clear that additional spectroscopic techniques are required to cover the large diversity of microplastics in the environment. Other mass spectrometry methods such as Pyrolysis-Gas Chromatography-Mass Spectrometry (Pyr-GC-MS) and Thermal Desorption-GC-MS (TED-GC-MS) have been used as an analytical method for the identification of microplastics in the environment [11]. However, both of these mass spectrometry methods also present significant drawbacks, including the most important deficiency of their inability to be used in the field.…”