Yuan Bojie, Sui Minghao, Lu Hongtao, Wang Jingyu, Qin Jie
Shanghai Institute of Pollution Control and Ecological Security, State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University 1239 Siping Road Shanghai 200092 People's Republic of China
RSC Adv. 2019 Dec 24;10(1):228-235. doi: 10.1039/c9ra09261g. eCollection 2019 Dec 20.
Understanding the effect of various environmental factors on the transformation of silver nanoparticles (Ag NPs) is crucial to determine their toxicity and fate in the environment. Ag NPs are inevitably exposed to sunlight and will be in contact with chloride (Cl), a ubiquitous ligand in natural water, once released into the environment. In this study, the combined effect of Cl and light on various physicochemical properties (optical property, dissolution, morphology, surface charge) of different sizes Ag NPs was studied. The results showed that light irradiation, in the presence of Cl, led to a great decrease in the concentration of dissolved Ag and a remarkable increase in the zeta potential of Ag NPs, as well as the generation of some tiny Ag NPs and fusion aggregates. AgCl was suggested to rapidly coat onto Ag NPs after exposure to Cl. And the AgCl layer was obviously destroyed by photoreduction under light irradiation. Meanwhile, the Ag NP size exhibited a great impact on the destruction of the AgCl layer. It was further observed that the AgCl layer gradually re-formed when the light was removed, which suggested that Ag NPs might present different states during the daytime and at night in aquatic environments.
了解各种环境因素对银纳米颗粒（Ag NPs）转化的影响对于确定其在环境中的毒性和归宿至关重要。Ag NPs不可避免地会暴露在阳光下，一旦释放到环境中，就会与天然水中普遍存在的配体氯（Cl）接触。在本研究中，研究了Cl和光对不同尺寸Ag NPs的各种物理化学性质（光学性质、溶解性、形态、表面电荷）的综合影响。结果表明，在Cl存在的情况下进行光照，会导致溶解态Ag浓度大幅降低，Ag NPs的zeta电位显著增加，同时还会生成一些微小的Ag NPs和融合聚集体。研究表明，Ag NPs在接触Cl后会迅速被AgCl包覆。并且在光照下，AgCl层会因光还原作用而明显被破坏。同时，Ag NPs的尺寸对AgCl层的破坏有很大影响。进一步观察到，当光照去除后，AgCl层会逐渐重新形成，这表明在水生环境中，Ag NPs在白天和夜晚可能呈现不同的状态。
