Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
Sci Total Environ. 2024 May 15;925:171563. doi: 10.1016/j.scitotenv.2024.171563. Epub 2024 Mar 8.
The transport of nanoplastics (NPs) in porous media has received a lot of attention, but the studies on the long-term release of NPs retained in porous media and the particle fracture during this process are seriously lacking. For filling this deficiency, we examined the individual or synergistic effects of surfactants, natural organic matters (NOMs), antibiotics, and bacteria on the desorption, long-term release, and particle fracture behaviors of polystyrene NPs (PS-NPs) retained in porous media. It was found that the change in hydrophilicity of PS-NPs dominated the long-term release of PS-NPs retained in porous media when surfactants were present. In the single system of surfactants and the dual system of surfactants and NOMs, the release of PS-NPs were improved owing to the increasing hydrophilicity of PS-NPs, although cationic surfactants also reduced the electrostatic repulsion between PS-NPs and porous media. Increasing antibiotic concentration reduced the electrostatic repulsion between PS-NPs and porous media to inhibit the release of PS-NPs. When bacteria were present whether containing antibiotics or not, the effects on roughness of PS-NPs dominated the release of PS-NPs. The effects of surfactants and NOMs on the PS-NP desorption were similar with the long-term release, with changes in hydrophilicity dominating the process. Whereas the effects of antibiotics and bacteria on the PS-NP desorption were different with the long-term release. Surfactants and NOMs in the presence of surfactants inhibited the fracture of PS-NPs by increasing the hydrophilicity of PS-NPs brought about the coating of water molecules on PS-NPs for protection. Antibiotics had no significant effects on the fracture of PS-NPs due to unaltered vertical forces on PS-NPs and no protective effect. Bacteria in the presence or absence of antibiotics inhibited the fracture of PS-NPs by coating PS-NPs retained in porous media to protect PS-NPs from fracture.
纳米塑料（NPs）在多孔介质中的迁移受到了广泛关注，但有关滞留在多孔介质中的 NPs 的长期释放以及在此过程中颗粒破裂的研究却严重缺乏。为了弥补这一不足，我们研究了表面活性剂、天然有机物（NOMs）、抗生素和细菌对滞留在多孔介质中的聚苯乙烯 NPs（PS-NPs）的解吸、长期释放和颗粒破裂行为的单独或协同作用。结果表明，当存在表面活性剂时，PS-NPs 的亲水性变化主导了滞留在多孔介质中的 PS-NPs 的长期释放。在表面活性剂单一体系和表面活性剂与 NOMs 的双重体系中，PS-NPs 的释放得到了改善，这是由于 PS-NPs 的亲水性增加，尽管阳离子表面活性剂也降低了 PS-NPs 与多孔介质之间的静电排斥。随着抗生素浓度的增加，PS-NPs 与多孔介质之间的静电排斥减少，从而抑制了 PS-NPs 的释放。当存在细菌时，无论是否含有抗生素，PS-NPs 的粗糙度对 PS-NPs 的释放起主导作用。表面活性剂和 NOMs 对 PS-NP 解吸的影响与长期释放相似，亲水性的变化起主导作用。而抗生素和细菌对 PS-NP 解吸的影响与长期释放不同。在存在表面活性剂和 NOMs 的情况下，它们通过增加 PS-NPs 的亲水性来抑制 PS-NPs 的破裂，这是由于水分子在 PS-NPs 上的涂层起到了保护作用。抗生素由于对 PS-NPs 垂直力没有改变，并且没有保护作用，因此对 PS-NPs 的破裂没有显著影响。有或没有抗生素的细菌通过在多孔介质中包裹 PS-NPs 来抑制 PS-NPs 的破裂，从而保护 PS-NPs 免受破裂。
