Nguyen Thanh-Binh, Ho Thi-Bao-Chau, Chen Chiu-Wen, Bui Xuan-Thanh, Chen Wei-Hsin, Dong Cheng-Di
Institute of Aquatic Science and Technology, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan.
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.
Sci Total Environ. 2025 Jan 10;959:178144. doi: 10.1016/j.scitotenv.2024.178144. Epub 2024 Dec 21.
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 mmol·g. Notably, the adsorption capacity decreased to 0.260 × 10 mmol·g after 1 day, 0.326 × 10 mmol·g after 3 days, and 0.514 × 10 mmol·g 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.
紫外线（UV）对结构变化的影响是一个重大问题，特别是关于微塑料（MPs）的风化和老化影响。本研究着重考察不同紫外线波长（UVC、UVB和UVA）如何影响老化聚乙烯（PE）微塑料对四环素（TC）的吸附行为。为详细探究吸附机制，研究了不同紫外线波长下的吸附动力学。暴露于紫外线的PE微塑料吸附速率较慢，顺序如下：原始PE > PE微塑料/UVA > PE微塑料/UVB > PE微塑料/UVC。该研究还评估了延长UVC照射后吸附机制的变化。使用朗缪尔模型确定原始PE微塑料的吸附容量，发现为1.497×10 mmol·g。值得注意的是，吸附容量在1天后降至0.260×10 mmol·g，3天后降至0.326×10 mmol·g，7天后降至0.514×10 mmol·g。表面表征分析表明，紫外线照射导致PE微塑料表面由于羟基自由基的产生而形成新的含氧官能团（OFGs），如羰基和羟基。此外，照射引起的表面熔化增加了疏水性，导致TC吸附容量降低，因为TC是亲水性的。总体而言，本研究对不同紫外线波长对PE微塑料的影响进行了基本比较。
