Shanghai Key Laboratory for Urban Ecological Process and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
J Hazard Mater. 2021 Apr 5;407:124836. doi: 10.1016/j.jhazmat.2020.124836. Epub 2020 Dec 15.
Ageing process can significantly alter the structural properties, environmental behaviors and potential ecotoxicity of microplastics (MPs) in water. In this study, the structural properties of aged polystyrene (PS) MPs being exposed to UV/HO, UV/HO and UV/Cl artificially accelerated oxidation processes and related sorption behaviors of bisphenol A (BPA) on those virgin/aged PS were investigated. The surface oxidation and hydrophilicity of aged PS were significantly increased according to infrared spectroscopy (IR) and water contact angle (CA) measurements. The differential scanning calorimetric (DSC) and gel permeation chromatography (GPC) revealed apparent degradation of aged PS especially in their amorphous domain. Obviously deteriorative BPA sorption capacity on aged PS was observed compared with that of virgin PS. The sorption rates of BPA on aged PS were accelerated and sorption of BPA shifted from partition dominant mechanism on virgin PS to the adsorption dominant mechanism through being fitted with the dual-mode sorption model. Besides, ageing in UV/Cl system introduces C-Cl groups on the surface of PS which strengthen the combination with BPA through halogen bonding interaction. Salt and dissolved organic matters (DOM) in marine water may increase the BPA sorption on aged MPs due to enhanced polar interaction.
老化过程会显著改变水中微塑料（MPs）的结构特性、环境行为和潜在的生态毒性。在这项研究中，研究了暴露于 UV/HO、UV/HO 和 UV/Cl 人工加速氧化过程中的老化聚苯乙烯（PS） MPs 的结构特性，以及 virgin/aged PS 上双酚 A（BPA）的相关吸附行为。根据红外光谱（IR）和水接触角（CA）测量，发现老化 PS 的表面氧化和亲水性显著增加。差示扫描量热法（DSC）和凝胶渗透色谱（GPC）显示，老化 PS 明显降解，特别是在无定形区。与 virgin PS 相比，老化 PS 对 BPA 的吸附能力明显恶化。BPA 在老化 PS 上的吸附速率加快，BPA 的吸附从 virgin PS 上的分配主导机制转变为吸附主导机制，通过与双模式吸附模型拟合。此外，在 UV/Cl 体系中老化会在 PS 表面引入 C-Cl 基团，通过卤键相互作用加强与 BPA 的结合。海洋水中的盐和溶解有机物（DOM）可能会由于增强的极性相互作用而增加老化 MPs 上的 BPA 吸附。
