State Key Laboratory of Water Environment Simulation, School of Environment , Beijing Normal University , Beijing 100875 , People's Republic of China.
School of Environment and Civil Engineering , Dongguan University of Technology , Dongguan 523808 , People's Republic of China.
Environ Sci Technol. 2018 Apr 17;52(8):4842-4849. doi: 10.1021/acs.est.7b04547. Epub 2018 Jan 2.
This work investigates the effect of chloride ion (Cl) on dissolution, reactive oxygen species (ROS) generation, and toxicity of citrate-coated silver nanoparticles (AgNPs) under UV irradiation. The dissolution rate was decreased by 0.01 M Cl due to AgCl passivation on the AgNP surface. By contrast, high concentrations of Cl (0.1 or 0.5 M) promoted dissolution due to the formation of soluble Ag-Cl complexes (AgCl ). The generation of O in the AgNPs/Cl/UV system was promoted by 0.01 M Cl, whereas it was retarded by 0.1 or 0.5 M Cl, which was probably because the aggregation of AgNPs at high ionic strength reduced the nanoparticles' surface areas for radical formation. Additionally, Cl contributed to •OH generation in the AgNPs/Cl/UV system, in which the produced •OH concentrations increased with increasing Cl concentrations. The reduction reaction between silver ions and O resulted in lower dissolution rates of AgNPs/Cl mixtures under UV irradiation than those in the dark. The phototoxicity of AgNPs toward E. coli with different concentrations of Cl followed the order of 0.5 M > 0 M > 0.1 M > 0.01 M. Both ROS and dissolved Ag played significant role in the phototoxicity of AgNPs. This work demonstrates the potential importance of anions in the fate and biological impact of AgNPs.
本研究考察了氯离子（Cl）对光照下柠檬酸包覆的银纳米颗粒（AgNPs）溶解、活性氧（ROS）生成和毒性的影响。由于 AgCl 在 AgNP 表面的钝化作用，0.01 M Cl 使溶解速率降低。相比之下，高浓度的 Cl（0.1 或 0.5 M）促进了溶解，这是由于形成了可溶性的 Ag-Cl 配合物（AgCl）。在 AgNPs/Cl/UV 体系中，0.01 M Cl 促进了 O 的生成，而 0.1 或 0.5 M Cl 则减缓了 O 的生成，这可能是因为在高离子强度下 AgNPs 的聚集减少了自由基形成的纳米颗粒表面积。此外，Cl 有助于 AgNPs/Cl/UV 体系中 •OH 的生成，其中产生的 •OH 浓度随 Cl 浓度的增加而增加。Ag 离子与 O 的还原反应导致 AgNPs/Cl 混合物在光照下的溶解速率低于黑暗中。不同浓度 Cl 存在下 AgNPs 对大肠杆菌的光毒性顺序为 0.5 M > 0 M > 0.1 M > 0.01 M。ROS 和溶解的 Ag 都对 AgNPs 的光毒性有重要影响。本研究表明，阴离子在 AgNPs 的命运和生物影响中具有潜在的重要性。
