School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China.
Tianjin Engineering Center for technology of Protection and Function Construction of Ecological Critical Zone, Tianjin 300350, China; School of Environment Science & Engineering, Tianjin University, Tianjin 300350, China.
Sci Total Environ. 2022 Feb 10;807(Pt 3):151042. doi: 10.1016/j.scitotenv.2021.151042. Epub 2021 Oct 19.
The misuse of both antibiotics and plastics significantly increases the environmental pollution problems associated with these contaminants. Moreover, microplastics can adsorb other pollutants in the environment. However, the mechanisms of antibiotic adsorption by degradable and nondegradable microplastics are not completely understood. In this study, we investigated the environmental behavior of norfloxacin (NOR) using polybutylene succinate (PBS), which is a degradable microplastic, and compared it with conventional microplastics, polystyrene (PS) and polyethylene (PE). The order of adsorption capacity was PS > PBS ≫ PE. The adsorption behavior fitted well with the pseudo-second-order kinetic and Langmuir isotherm models, indicating monolayer adsorption. The process is thermodynamically endothermic and non-spontaneous and is controlled by chemical and physical mechanisms, including π-π conjugation, hydrogen bonds, ion exchange, and electrostatic interactions. The adsorption capacity of microplastics was higher when the solution pH was around the pKa value of NOR than at other pH values. Ionic strength and dissolved organic matter inhibited the adsorption process. For PS and PBS, the amount of NOR adsorbed onto MPs initially decreased and then increased with the increase of coexisting heavy metal ions. Zn and Pb could promote the adsorption of NOR by PE. This study reveals the interaction mechanisms between microplastics and antibiotics and provides a more comprehensive theoretical basis for an ecological environmental risk assessment of different microplastics.
抗生素和塑料的滥用显著增加了这些污染物相关的环境污染问题。此外，微塑料可以吸附环境中的其他污染物。然而，可降解和不可降解微塑料吸附抗生素的机制尚不完全清楚。在这项研究中，我们使用聚丁二酸丁二醇酯（PBS）研究了诺氟沙星（NOR）的环境行为，PBS 是一种可降解的微塑料，并将其与传统微塑料聚苯乙烯（PS）和聚乙烯（PE）进行了比较。吸附容量的顺序为 PS > PBS > PE。吸附行为很好地符合伪二阶动力学和朗缪尔等温线模型，表明单层吸附。该过程是热力学吸热和非自发的，受化学和物理机制控制，包括π-π共轭、氢键、离子交换和静电相互作用。当溶液 pH 值接近 NOR 的 pKa 值时，微塑料对 NOR 的吸附容量高于其他 pH 值时的吸附容量。离子强度和溶解有机物抑制了吸附过程。对于 PS 和 PBS，与 MPs 共存的重金属离子的量增加，NOR 的吸附量最初减少，然后增加。Zn 和 Pb 可以促进 PE 对 NOR 的吸附。本研究揭示了微塑料和抗生素之间的相互作用机制，为不同微塑料的生态环境风险评估提供了更全面的理论基础。
