聚乙烯及聚丙烯对抗生素的吸附行为研究

The Study of Adsorption Behavior of Antibiotics onto Polyethylene and Polypropylene

该研究选取微塑料聚丙烯(PP)和聚乙烯(PE)以及抗生素磺胺嘧啶(SDZ)和环丙沙星(CIP)为研究对象,探讨了在海水和纯水中的抗生素在微塑料上的吸附行为。研究结果表明:在不同背景溶液下微塑料对抗生素的吸附能力从大到小依次为:PP-纯水>PE-纯水>PP-海水>PE-海水;抗生素吸附能力从大到小依次为:CIP-纯水>SDZ-纯水>SDZ-海水>CIP-海水。除在海水体系中,PE对SDZ的吸附过程使用准一级动力学模型拟合效果较好外,其他吸附均符合准二级动力学模型,起始阶段吸附较快,随后吸附变慢,最终达到动态平衡。Freundlich模型对等温吸附过程拟合效果较好,表明吸附为非均匀的多层吸附,存在多个吸附位点。使用傅里叶红外光谱仪分析发现在吸附过程中没有产生新的基团,即没有化学吸附。不同微塑料对SDZ和CIP的吸附存在差异,且不同的水环境因素影响较为明显,微塑料在海水中的吸附能力低于纯水。这些结果可为了解微塑料作为载体协同迁移抗生素提供理论依据。

To explore the adsorption mechanism of antibiotics onto microplastics, polypropylene(PP), polyethylene(PE),sulfadiazine(SDZ) and ciprofloxacin(CIP) were selected as the study objects, the adsorption behavior of antibiotics onto plastic in seawater and pure water was discussed. The experimental results indicated that the adsorption capacity of microplastics to antibiotics in different media was ranged from large to small such as PP-purewater>PE-purewater>PP-seawater>PEseawater;The sequence in which antibiotics were easily adsorbed such as CIP-purewater>SDZ-purewater>SDZ-seawater>CIP-seawater. The adsorption of SDZ onto PE in seawater was in line with the quasi-first-stage kinetic model(R^(2)>0.92), other adsorption processes obeyed to the quasi-second-stage kinetic model, The adsorption was faster in the initial stage, then got slows down, and finally a dynamic equilibrium was reached. The Freundlich model can simulate the isothermal adsorption process, that indicated the adsorption was heterogeneous multilayer. The analysis of FTIR showed that no new groups were generated in the adsorption process, namely, there is no chemical reaction in the adsorption process. The adsorption of SDZ and CIP was different in different microplastics, and the influence of water background was also obvious. These results could provide a theoretical basis for understanding microplastics as a carrier to collaborative migration of antibiotics.