title: Surface-coating-dependent dissolution, aggregation, and reactive oxygen species (ROS) generation of silver nanoparticles under different irradiation conditions.
abstract: Dissolution, aggregation, and reactive oxygen species (ROS) generation are three major processes that silver nanoparticles (AgNPs) undergo in aqueous environments. In this study, the effects of AgNP surface coatings on these three processes were systematically evaluated under three irradiation conditions (UV-365, UV-254, and xenon lamp) to advance knowledge on the environmental fate and photochemical kinetics of AgNPs. The AgNPs used were (a) bare-AgNPs, (b) electrostatically stabilized citrate-AgNPs, and (c) sterically stabilized polyvinylpyrrolidone-AgNPs (PVP-AgNPs), and the light exposures greatly promoted the three processes. Both the 5-h released Ag(+) concentrations and the 2.5-h aggregation rate followed the order UV-365 > xenon lamp > UV-254 for all three types of AgNPs. For all irradiation conditions, the 5-h released Ag(+) concentration was highest for bare-AgNPs, followed by PVP-AgNPs and citrate-AgNPs; the 2.5-h aggregation rate was highest for bare-AgNPs, followed by citrate-AgNPs and PVP-AgNPs, which indicated that surface coating significantly determines the process kinetics of AgNPs. Under UV-365 irradiation, the bare-AgNPs generated superoxide and hydroxyl radicals, but the citrate-AgNPs yielded only superoxide radical, and the PVP-AgNPs did not generate any ROS. This study highlights the different fates and kinetic behaviors of AgNPs during photochemical interactions, providing important insight into the environmental implications of AgNP release.
authors: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University , Beijing 100875, People's Republic of China.
authors: Yang
authors: Y
authors: Li
authors: Wen
authors: W
authors: Zhang
authors: Junfeng
authors: J
authors: Niu
authors: Yongsheng
authors: Y
authors: Chen
mesh_terms: D002951:Citrates / Q000737:chemistry; D005427:Flocculation; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D011205:Povidone / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry*; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects*; D012995:Solubility; D013499:Surface Properties
chemical_list: D002951:Citrates; D017382:Reactive Oxygen Species; D012834:Silver; D011205:Povidone