Details
Originalsprache | Englisch |
---|---|
Aufsatznummer | 101080 |
Fachzeitschrift | Environmental Challenges |
Jahrgang | 18 |
Frühes Online-Datum | 6 Jan. 2025 |
Publikationsstatus | Elektronisch veröffentlicht (E-Pub) - 6 Jan. 2025 |
Abstract
Microplastics (MP) in soils are considered an emerging environmental pollutant of global concern. The transport processes of MP in soils are poorly understood, which indicates a major knowledge gap regarding the environmental impact and behaviour of MP. Mobility and surface charge can be affected by ageing, mainly via UV irradiation. In the present study, 1 µm polystyrene microspheres (PS-MP) were aged with UV irradiation using an irradiance of 2.05 W m−2 (ultraviolet A, UVA; 365 nm) and 5.58 W m−2 (ultraviolet C, UVC; 254 nm) and different exposure times between 24 und 1176 hours to generate a gradient in MP ageing. The UV-ageing effects on PS-MP were characterised in terms of changes in particle size, zeta potential, and surface functional groups as determined by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Non-irradiated PS-MP microspheres were used as a control. Column tests were performed by percolating PS-MP microspheres suspended in CaCl2 solution (ionic strength 7.5 mM) through a quartz sand matrix (0.3 mm particle diameter). PS-MP sizes steadily decreased with increasing ageing time from 24 h to 1176 h for both UVA and UVC treatment. ATR-FTIR results revealed that UV irradiation induced a transformation of PS-MP surfaces with especially the appearance of a carbonyl (C=O) peak due to C-H bond breaking during the oxidation process. The increasing presence of oxygen-containing functional groups in UV-treated PS-MP led to an increasing negative surface charge and zeta potential and enhanced PS-MP transport through the quartz sand column. With increasing irradiation time, the aged PS-MP showed continuously increasing transport rates compared to the transport rates of non-aged PS-MP, ranging from 46 to 85% and 48 to 91% for UVA- and UVC-treated samples, respectively. The fastest breakthrough was observed for highest negative zeta potential and amount of O-containing functional groups as compared to control PS-MP, which enhanced electrostatic repulsion between aged PS-MP and quartz sand particles as was demonstrated from calculation of the interaction free energy. Our findings imply that UV irradiation changes the PS-MP surface physicochemical characteristics and transport potential by increasing the mobility of PS-MP and hence the risk for contamination of deeper soil layers and water bodies.
ASJC Scopus Sachgebiete
- Umweltwissenschaften (insg.)
- Globaler Wandel
- Umweltwissenschaften (insg.)
- Environmental engineering
- Umweltwissenschaften (insg.)
- Abfallwirtschaft und -entsorgung
- Umweltwissenschaften (insg.)
- Umweltverschmutzung
- Umweltwissenschaften (insg.)
- Management, Monitoring, Politik und Recht
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in: Environmental Challenges, Jahrgang 18, 101080, 04.2025.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - UV-ageing effects on polystyrene microplastics surface polarity and transport in soils
AU - Shafea, Leila
AU - Goebel, Marc O.
AU - Woche, Susanne K.
AU - Peth, Stephan
N1 - Publisher Copyright: © 2025
PY - 2025/1/6
Y1 - 2025/1/6
N2 - Microplastics (MP) in soils are considered an emerging environmental pollutant of global concern. The transport processes of MP in soils are poorly understood, which indicates a major knowledge gap regarding the environmental impact and behaviour of MP. Mobility and surface charge can be affected by ageing, mainly via UV irradiation. In the present study, 1 µm polystyrene microspheres (PS-MP) were aged with UV irradiation using an irradiance of 2.05 W m−2 (ultraviolet A, UVA; 365 nm) and 5.58 W m−2 (ultraviolet C, UVC; 254 nm) and different exposure times between 24 und 1176 hours to generate a gradient in MP ageing. The UV-ageing effects on PS-MP were characterised in terms of changes in particle size, zeta potential, and surface functional groups as determined by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Non-irradiated PS-MP microspheres were used as a control. Column tests were performed by percolating PS-MP microspheres suspended in CaCl2 solution (ionic strength 7.5 mM) through a quartz sand matrix (0.3 mm particle diameter). PS-MP sizes steadily decreased with increasing ageing time from 24 h to 1176 h for both UVA and UVC treatment. ATR-FTIR results revealed that UV irradiation induced a transformation of PS-MP surfaces with especially the appearance of a carbonyl (C=O) peak due to C-H bond breaking during the oxidation process. The increasing presence of oxygen-containing functional groups in UV-treated PS-MP led to an increasing negative surface charge and zeta potential and enhanced PS-MP transport through the quartz sand column. With increasing irradiation time, the aged PS-MP showed continuously increasing transport rates compared to the transport rates of non-aged PS-MP, ranging from 46 to 85% and 48 to 91% for UVA- and UVC-treated samples, respectively. The fastest breakthrough was observed for highest negative zeta potential and amount of O-containing functional groups as compared to control PS-MP, which enhanced electrostatic repulsion between aged PS-MP and quartz sand particles as was demonstrated from calculation of the interaction free energy. Our findings imply that UV irradiation changes the PS-MP surface physicochemical characteristics and transport potential by increasing the mobility of PS-MP and hence the risk for contamination of deeper soil layers and water bodies.
AB - Microplastics (MP) in soils are considered an emerging environmental pollutant of global concern. The transport processes of MP in soils are poorly understood, which indicates a major knowledge gap regarding the environmental impact and behaviour of MP. Mobility and surface charge can be affected by ageing, mainly via UV irradiation. In the present study, 1 µm polystyrene microspheres (PS-MP) were aged with UV irradiation using an irradiance of 2.05 W m−2 (ultraviolet A, UVA; 365 nm) and 5.58 W m−2 (ultraviolet C, UVC; 254 nm) and different exposure times between 24 und 1176 hours to generate a gradient in MP ageing. The UV-ageing effects on PS-MP were characterised in terms of changes in particle size, zeta potential, and surface functional groups as determined by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Non-irradiated PS-MP microspheres were used as a control. Column tests were performed by percolating PS-MP microspheres suspended in CaCl2 solution (ionic strength 7.5 mM) through a quartz sand matrix (0.3 mm particle diameter). PS-MP sizes steadily decreased with increasing ageing time from 24 h to 1176 h for both UVA and UVC treatment. ATR-FTIR results revealed that UV irradiation induced a transformation of PS-MP surfaces with especially the appearance of a carbonyl (C=O) peak due to C-H bond breaking during the oxidation process. The increasing presence of oxygen-containing functional groups in UV-treated PS-MP led to an increasing negative surface charge and zeta potential and enhanced PS-MP transport through the quartz sand column. With increasing irradiation time, the aged PS-MP showed continuously increasing transport rates compared to the transport rates of non-aged PS-MP, ranging from 46 to 85% and 48 to 91% for UVA- and UVC-treated samples, respectively. The fastest breakthrough was observed for highest negative zeta potential and amount of O-containing functional groups as compared to control PS-MP, which enhanced electrostatic repulsion between aged PS-MP and quartz sand particles as was demonstrated from calculation of the interaction free energy. Our findings imply that UV irradiation changes the PS-MP surface physicochemical characteristics and transport potential by increasing the mobility of PS-MP and hence the risk for contamination of deeper soil layers and water bodies.
KW - Polystyrene microspheres
KW - Surface polarity
KW - Transport
KW - UV-ageing
KW - Zeta potential
UR - http://www.scopus.com/inward/record.url?scp=85214556974&partnerID=8YFLogxK
U2 - 10.1016/j.envc.2025.101080
DO - 10.1016/j.envc.2025.101080
M3 - Article
AN - SCOPUS:85214556974
VL - 18
JO - Environmental Challenges
JF - Environmental Challenges
M1 - 101080
ER -