Influence of UV wavelength variations on tetracycline adsorption by polyethylene microplastics in aquatic environments

Thanh-Binh Nguyen; Thi-Bao-Chau Ho; Chiu-Wen Chen; Xuan-Thanh Bui; Wei-Hsin Chen; Cheng-Di Dong

doi:10.1016/j.scitotenv.2024.178144

Influence of UV wavelength variations on tetracycline adsorption by polyethylene microplastics in aquatic environments

Sci Total Environ. 2024 Dec 20:959:178144. doi: 10.1016/j.scitotenv.2024.178144. Online ahead of print.

Authors

Thanh-Binh Nguyen¹, Thi-Bao-Chau Ho¹, Chiu-Wen Chen², Xuan-Thanh Bui³, Wei-Hsin Chen⁴, Cheng-Di Dong⁵

Affiliations

¹ Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan.
² Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan; Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan.
³ Key Laboratory of Advanced Waste Treatment Technology, Ho Chi Minh City University of Technology (HCMUT), Vietnam National University Ho Chi Minh (VNU-HCM), Thu Duc city, Ho Chi Minh City 700000, Viet Nam; Faculty of Environment and Natural Resources, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City 700000, Viet Nam.
⁴ Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan.
⁵ Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan; Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan. Electronic address: [email protected].

PMID: 39709844
DOI: 10.1016/j.scitotenv.2024.178144

Abstract

The effect of ultraviolet (UV) light on structural changes is a significant concern, particularly regarding the weathering and aging effects on microplastics (MPs). This research focused on examining how various UV light wavelengths (UVC, UVB, and UVA) influence the adsorption behavior of aged polyethylene (PE) MPs toward tetracycline (TC). To explore the adsorption mechanism in detail, adsorption kinetics were studied under different UV light wavelengths. PE MPs exposed to UV light exhibited a slower adsorption rate in the following order: virgin PE > PE MPs/UVA > PE MPs/UVB > PE MPs/UVC. The study also evaluated changes in the adsorption mechanism with prolonged UVC irradiation. The Langmuir model was used to determine the adsorption capacity of virgin PE MPs, which was found to be 1.497 × 10^-2 mmol·g^-1. Notably, the adsorption capacity decreased to 0.260 × 10^-2 mmol·g^-1 after 1 day, 0.326 × 10^-2 mmol·g^-1 after 3 days, and 0.514 × 10^-2 mmol·g^-1 after 7 days. Surface characterization analysis revealed that UV irradiation led to the formation of new oxygenated functional groups (OFGs), such as carbonyl and hydroxyl groups, on the PE MPs surface due to the generation of OH radicals. Additionally, surface melting caused by irradiation increased hydrophobicity, resulting in reduced TC adsorption capacity, as TC is hydrophilic. Overall, this study provides a fundamental comparison of the effects of different UV light wavelengths on PE MPs.

Keywords: Adsorption; Aging; Microplastics; Tetracycline; UV light.