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Microplastic occurrence during the pre-treatment of polypropylene in a simulated washing process for mechanical recycling
Summary
This study investigated microplastic emissions during the washing of post-consumer polypropylene plastic waste as part of mechanical recycling pre-treatment. Washing generated measurable microplastic particles, with higher temperatures and longer contact times increasing emissions — a finding relevant to understanding recycling facilities as potential microplastic pollution sources.
Abstract In this study, the micro-plastic emission during polypropylene washing was investigated. Washing post-consumer waste before the re-granulation step is an important process to remove contaminants on the waste material which can interfere with downstream processing and product quality. To simulate a pre-treatment step during mechanical recycling, an industrial washing machine with two different temperatures (30 °C and 60 °C) and residence times (5 min and 15 min) was used. The whole washing effluent was filtered, gravimetrically quantified and with DSC measurements qualitatively identified. Results suggest a release of micro-plastics during washing whereby the residence time has about a two-fold higher impact on possible emissions than temperature. Graphical abstract
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