Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Water Res. 2023 Jul 15;240:120111. doi: 10.1016/j.watres.2023.120111. Epub 2023 May 21.
Due to the increasing applications, silver nanoparticles (AgNPs) are inevitably released into the environments and are subjected to various transformations. Chloride ion (Cl) is a common and abundant anion with a wide range of concentration in aquatic environments and exhibits a strong affinity for silver. The results indicate that AgNPs experienced multistep chlorination, which was dependent on the concentration of Cl in a non-linear manner. The dissolution of AgNPs was accelerated at Cl/Ag ratio of 1 and the intensive etching effect of Cl contributed to the significant morphology changes of AgNPs. The dissolved Ag quickly precipitated with Cl to form an amorphous and passivating AgCl(s) layer on the surface of AgNPs, thus the dissolution rate of AgNPs decreased at higher Cl/Ag ratios (100 and 1000). As the Cl/Ag ratio further increased to 10,000, the overall transformation rate increased remarkably due to the complexation of Cl with AgCl(s) to form soluble AgCl species, which was verified by the reaction of AgCl nanoparticles with Cl. Besides, several environmental factors (electrolytes, surfactants and natural organic matter) affected AgNPs dissolution and the following chlorination. These results will expand the understanding of the environmental fate and potential risks of AgNPs in natural chloride-rich waters.
由于应用的增加，银纳米粒子（AgNPs）不可避免地会释放到环境中，并经历各种转化。氯离子（Cl）是一种常见且丰富的阴离子，在水生环境中的浓度范围很广，对银表现出很强的亲和力。结果表明，AgNPs 经历了多步氯化，这与 Cl 的浓度呈非线性关系。在 Cl/Ag 比为 1 时，AgNPs 的溶解速度加快，Cl 的强烈刻蚀作用导致 AgNPs 的形貌发生显著变化。溶解的 Ag 迅速与 Cl 结合，在 AgNPs 表面形成非晶态和钝化的 AgCl(s)层，因此在较高的 Cl/Ag 比（100 和 1000）下，AgNPs 的溶解速率降低。当 Cl/Ag 比进一步增加到 10000 时，由于 Cl 与 AgCl(s)的络合形成可溶的 AgCl 物种，整体转化速率显著增加，这可以通过 AgCl 纳米粒子与 Cl 的反应得到验证。此外，一些环境因素（电解质、表面活性剂和天然有机物）影响 AgNPs 的溶解和随后的氯化。这些结果将扩大对富含氯离子的天然水中 AgNPs 的环境归宿和潜在风险的认识。
