Enhancing microplastics degradation using Fe-rich red yellow latosols: a fenton and photocatalytic approach
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Date
2024-11-01
Authors
Wijekoon, Ishani M.
Koralegedara, Nadeesha H.
Rodrigo, Sanjeewa K.
Journal Title
Journal ISSN
Volume Title
Publisher
Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka
Abstract
Microplastics (MPs) have a long persistence in the environment due to their slow natural degradation. Fenton process and photo-catalytic reactions, where Fe plays a major role, have the potential of degrading polymers. This study aimed to investigate the impact of natural iron-rich soil on the degradation of MPs via the Fenton process and photo-catalytic reactions. Secondary MPs (< 2 mm) were manually prepared from polyethylene (PE), polypropylene (PP), poly-ethylene-terephthalate (PET), high density polyethylene (HDPE), polystyrene (PS) and polyamide (PA) and mixed separately with Fe-rich soil (red yellow latosols-RE) and Fe-low soil (immature brown loamy soil-GS) at a ratio of 40 pieces/20 g of soil. Two separate experimental set-ups were maintained for visible light (standard incandescent light bulb > 400 nm) and UV light (UV bulb in a black box-360 nm) conditions. Samples were in saturated moisture condition. A control experiment was performed without soil but with moisture only. No measures were taken to control microbial activity in any of the set-ups. After 24 hours of exposure, MPs were recovered by handpicking, weighed and analysed for morphological changes and structural modifications using SEM, FT-IR and Raman spectroscopy. The highest weight loss was observed in PE-RE (1.1%), PP-RE (2.1%) and PS-RE (1.9%) mixtures exposed to UV light. A weight increase was observed in HDPE-RE, PET-RE and PA-RE due to strong aggregations of soil particles on MPs surface. According to the variations of peak positions and intensities of FT-IR and Raman spectroscopy, PE, PET, HDPE, PS and PA showed a relatively higher degradation with Fe-rich soil compared to Fe-low soil under UV light. Even though slight surface changes were observed under SEM, complete degradation was not observed within 24 hours. However, the data confirmed that the Fe-rich soils can enhance the MPs degradation. The experiments are underway to determine the optimum time required for maximum MPs degradation.
Description
Keywords
Degradation , Iron-rich soils , Microplastics , Photocatalysis
Citation
Proceedings of the Postgraduate Institute of Science Research Congress (RESCON) -2024, University of Peradeniya, P 33