College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai, 201306, PR China.
Shanghai Waterway Engineering Design and Consulting Co,. LTD., Shanghai, 200120, PR China.
Chemosphere. 2020 Dec;260:127650. doi: 10.1016/j.chemosphere.2020.127650. Epub 2020 Jul 10.
In recent years, the composite pollution of microplastics with organic pollutants and heavy metal ions in the water environment, including their combined toxicity, has received increasing attention. However, the mechanism underlying the joint effect of antibiotics and heavy metals on the surface behavior of microplastics has not been reported. The primary purpose of this article was to analyze the adsorption of levofloxacin (OFL) onto polyvinyl chloride (PVC) in an aqueous solution. The adsorption behavior was studied using kinetics, thermodynamics, and isotherm models, and the effects of several environmental factors, such as ionic strength, fulvic acid, and heavy metals, were determined. The adsorption kinetics and isotherms models indicated that the whole adsorption process was controlled by both intraparticle and outer diffusion, as well as chemical adsorption, which was the dominant mechanism. Based on the results of the thermodynamic experiment, the adsorption process was a nonspontaneous and exothermic reaction process. Furthermore, the presence of Cu, Zn, and Cr ions significantly promoted the adsorption of OFL, but the presence of Cd and Pb ions inhibited its adsorption. At the same time, the presence of the ionic strength and fulvic acid remarkably restricted the adsorption process. These findings confirmed that electrostatic interactions, ion exchange, intermolecular hydrogen bonds, and halogen bond cooperation were the main adsorption mechanisms. This paper mainly discusses the interaction between combinations of pollutants with microplastics, which provides theoretical guidance for the interface behavior, migration and transformation of marine microplastics in the actual environment.
近年来，水环境中微塑料与有机污染物和重金属离子的复合污染及其复合毒性受到越来越多的关注。然而，抗生素和重金属联合作用对微塑料表面行为的机制尚未报道。本文主要分析了左氧氟沙星（OFL）在水溶液中对聚氯乙烯（PVC）的吸附。通过动力学、热力学和等温线模型研究了吸附行为，并确定了几种环境因素（如离子强度、腐殖酸和重金属）的影响。吸附动力学和等温线模型表明，整个吸附过程由内扩散和外扩散以及化学吸附共同控制，化学吸附是主要机制。根据热力学实验的结果，吸附过程是一个非自发的放热反应过程。此外，Cu、Zn 和 Cr 离子的存在显著促进了 OFL 的吸附，而 Cd 和 Pb 离子的存在则抑制了其吸附。同时，离子强度和腐殖酸的存在显著限制了吸附过程。这些发现证实了静电相互作用、离子交换、分子间氢键和卤键协同作用是主要的吸附机制。本文主要讨论了污染物与微塑料组合之间的相互作用，为海洋微塑料在实际环境中的界面行为、迁移和转化提供了理论指导。
