UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics
During environmental migration, large plastic fragments can undergo degradation into microplastics (MPs), posing a significant threat to ecosystems. A research gap exists in understanding how MPs age in complex environments. We modeled aging by integrating an aging index with degradation kinetics. T...
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Frontiers Media S.A.
2025-05-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2025.1519668/full |
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| author | Liu Gao Liu Gao Liu Gao Liu Gao Yuanyuan Su Yuanyuan Su Tariq Mehmood Zezheng Wang Licheng Peng Licheng Peng Naiming Zhang Naiming Zhang |
| author_facet | Liu Gao Liu Gao Liu Gao Liu Gao Yuanyuan Su Yuanyuan Su Tariq Mehmood Zezheng Wang Licheng Peng Licheng Peng Naiming Zhang Naiming Zhang |
| author_sort | Liu Gao |
| collection | DOAJ |
| description | During environmental migration, large plastic fragments can undergo degradation into microplastics (MPs), posing a significant threat to ecosystems. A research gap exists in understanding how MPs age in complex environments. We modeled aging by integrating an aging index with degradation kinetics. This study investigated the degradation of MPs (polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC)) exposed to ultraviolet radiation in seawater. Aged MPs exhibited cracks, oxidized particles, and wrinkles on their surfaces. The functional groups experienced stretching (e.g., -OH, C-H, C=O) and bending (e.g., X-H in-plane, C-H in-plane), as identified through Fourier transform infrared spectroscopy (FTIR). Meanwhile, the crystallinity of MPs increased initially but decreased over time. The roughness and carbonyl index (CI) of MPs was increased as the weathering time progressed. mPE and mPP exhibited the most pronounced aging. The Elovich kinetic model poorly fitted the CI for aged MPs. A First-order kinetic improvement model fitted well but lacked clear parameter significance. The degradation mechanisms of mPE and mPP were similar. The benzene ring structure in mPS and dechlorination experienced by mPVC render them resistant to degradation. This study provides evidence that that enhances our understanding of the mechanisms underlying the aging process of MPs in seawater. |
| format | Article |
| id | doaj-art-63096a8cf642492b9385514b2edea75c |
| institution | OA Journals |
| issn | 2296-7745 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj-art-63096a8cf642492b9385514b2edea75c2025-08-20T02:27:13ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-05-011210.3389/fmars.2025.15196681519668UVA-induced weathering of microplastics in seawater: surface property transformations and kineticsLiu Gao0Liu Gao1Liu Gao2Liu Gao3Yuanyuan Su4Yuanyuan Su5Tariq Mehmood6Zezheng Wang7Licheng Peng8Licheng Peng9Naiming Zhang10Naiming Zhang11College of Resources and Environment, Yunnan Agricultural University, Kunming, ChinaKey Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, ChinaSchool of Environmental Science and Engineering, Hainan University, Haikou, ChinaYunnan Soil Fertility and Pollution Restoration Laboratory, Yunnan Agricultural University, Kunming, ChinaKey Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, ChinaSchool of Environmental Science and Engineering, Hainan University, Haikou, ChinaDepartment Sensors and Modeling, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, GermanyState Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, ChinaKey Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, Hainan University, Haikou, ChinaSchool of Environmental Science and Engineering, Hainan University, Haikou, ChinaCollege of Resources and Environment, Yunnan Agricultural University, Kunming, ChinaYunnan Soil Fertility and Pollution Restoration Laboratory, Yunnan Agricultural University, Kunming, ChinaDuring environmental migration, large plastic fragments can undergo degradation into microplastics (MPs), posing a significant threat to ecosystems. A research gap exists in understanding how MPs age in complex environments. We modeled aging by integrating an aging index with degradation kinetics. This study investigated the degradation of MPs (polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC)) exposed to ultraviolet radiation in seawater. Aged MPs exhibited cracks, oxidized particles, and wrinkles on their surfaces. The functional groups experienced stretching (e.g., -OH, C-H, C=O) and bending (e.g., X-H in-plane, C-H in-plane), as identified through Fourier transform infrared spectroscopy (FTIR). Meanwhile, the crystallinity of MPs increased initially but decreased over time. The roughness and carbonyl index (CI) of MPs was increased as the weathering time progressed. mPE and mPP exhibited the most pronounced aging. The Elovich kinetic model poorly fitted the CI for aged MPs. A First-order kinetic improvement model fitted well but lacked clear parameter significance. The degradation mechanisms of mPE and mPP were similar. The benzene ring structure in mPS and dechlorination experienced by mPVC render them resistant to degradation. This study provides evidence that that enhances our understanding of the mechanisms underlying the aging process of MPs in seawater.https://www.frontiersin.org/articles/10.3389/fmars.2025.1519668/fullaging timecarbonyl indexkineticsmicroplasticsultraviolet radiation |
| spellingShingle | Liu Gao Liu Gao Liu Gao Liu Gao Yuanyuan Su Yuanyuan Su Tariq Mehmood Zezheng Wang Licheng Peng Licheng Peng Naiming Zhang Naiming Zhang UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics Frontiers in Marine Science aging time carbonyl index kinetics microplastics ultraviolet radiation |
| title | UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics |
| title_full | UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics |
| title_fullStr | UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics |
| title_full_unstemmed | UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics |
| title_short | UVA-induced weathering of microplastics in seawater: surface property transformations and kinetics |
| title_sort | uva induced weathering of microplastics in seawater surface property transformations and kinetics |
| topic | aging time carbonyl index kinetics microplastics ultraviolet radiation |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2025.1519668/full |
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