Sunlight-Driven Reduction of Silver Ions by Natural Organic Matter: Formation and Transformation of Silver Nanoparticles

Hou, Wen Che; Stuart, Brittany; Howes, Roberta; Zepp, Richard G.

doi:10.1021/es400802w

Cited by 166 publications

(188 citation statements)

References 61 publications

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“…As NOM has intense light absorption in the UV−vis region, this observed leveling-off phenomenon of the formation rate was possibly caused by the light attenuation of NOM. 20 This speculation was further supported by photoreduction of Ag + by M f -NOM at different NOM concentrations. At 1 mg L −1 DOC of M f -NOM, the difference in the reductive ability of M f -NOM was not significant (SI Figure S14).…”

Section: ■ Results and Discussionmentioning

confidence: 81%

“…In addition, AgNPs over 100 nm in size and suggest that the binding of Ag + to NOM plays an important role in this reduction process. 20 Electrostatic and steric stabilization provided by NOM adsorbed on the surfaces of AgNPs may prevent aggregation. 50 This dispersion effect of NOM on AgNPs could inhibit the fusion-induced growth of AgNPs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Photoreduction and Stabilization Capability of Molecular Weight Fractionated Natural Organic Matter in Transformation of Silver Ion to Metallic Nanoparticle

Yin

Shen²,

Zhou³

et al. 2014

Environ. Sci. Technol.

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Photoinduced reduction of silver ion (Ag + ) to silver nanoparticles (AgNPs) by dissolved organic matter (DOM) plays a crucial role in the transformation and transport of engineered AgNPs and Ag + in aquatic environments. DOM is a mixture of natural polymers with wide molecular weight (MW) distribution, and the roles of specific components of DOM in the photoreduction of Ag + to AgNPs are still not understood. In this study, MW fractionated natural organic matter (M f -NOM) were investigated for their roles on the photoreduction process and stabilization of the formed AgNPs. This photoinduced reduction process depends highly on pH, concentration of Ag + and NOM, light quality, and the MW of M f -NOM. Monochromatic radiation and light attenuation correction suggested that the difference of M f -NOM on reduction was mainly ascribed to the differential light attenuation of M f -NOM rather than the "real" reductive ability. More importantly, compared with low MW fractions, the high MW M f -NOMs exhibit drastically higher capability in stabilizing the photosynthesized AgNPs against Ca 2+ -induced aggregation. This finding is important for a better understanding of the differential roles of M f -NOM in the transformation and transport of Ag + and engineered AgNPs in DOMrich surface water.

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Section: ■ Results and Discussionmentioning

confidence: 81%

Section: ■ Results and Discussionmentioning

confidence: 99%

Photoreduction and Stabilization Capability of Molecular Weight Fractionated Natural Organic Matter in Transformation of Silver Ion to Metallic Nanoparticle

Yin

Shen²,

Zhou³

et al. 2014

Environ. Sci. Technol.

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“…These fractions have been shown to adsorb at the surface of nanoparticles, causing their aggregation [130,133] and limiting their Ag + release [97]. Humic acid has also the capability to immobilize Ag + ions and is a mild reducer, leading to the formation of new Ag NPs after dissolution of the original ones [134][135][136], with influences on the Ag + release dynamics. Additionally, DOM can immobilize other species, such as divalent cations [137].…”

Section: Fate Of Silver Nanoparticles In the Environmentmentioning

confidence: 99%

Antibacterial activity of silver nanoparticles: A surface science insight

2015

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Summary Silver nanoparticles constitute a very promising approach for the development of new antimicrobial systems. Nanoparticulate objects can bring significant improvements in the antibacterial activity of this element, through specific effect such as an adsorption at bacterial surfaces. However, the mechanism of action is essentially driven by the oxidative dissolution of the nanoparticles, as indicated by recent direct observations. The role of Ag + release in the action mechanism was also indirectly observed in numerous studies, and explains the sensitivity of the antimicrobial activity to the presence of some chemical species, notably halides and sulfides which form insoluble salts with Ag + . As such, surface properties of Ag nanoparticles have a crucial impact on their potency, as they influence both physical (aggregation, affinity for bacterial membrane, etc.) and chemical (dissolution, passivation, etc.) phenomena. Here, we review the main parameters that will affect the surface state of Ag NPs and their influence on antimicrobial efficacy. We also provide an analysis of several works on Ag NPs activity, observed through the scope of an oxidative Ag + release.

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“…Recent studies have suggested that both Ag NPs and Ag ions can induce cytotoxicity through different mechanism [2][3][4]. Additionally, numerous studies have suggested that Ag NPs are prone to oxidation and can release Ag ions to the surrounding environment, and that reverse formation to NPs from Ag ions is also a possibility [5][6][7][8]. The determination of the amount of both Ag NPs and Ag ions, instead of total Ag concentration in a sample is important to allow a sound correlation to be established between each Ag species and any toxicity effects.…”

Section: Introductionmentioning

confidence: 99%

Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles

Mudalige

Linder

2016

Journal of Chromatography A

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Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg −1 of silver nanoparticles and 0.03 μg kg −1 of ionic silver. Nanoparticles of varied sizes (10-110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low.

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Sunlight-Driven Reduction of Silver Ions by Natural Organic Matter: Formation and Transformation of Silver Nanoparticles

Cited by 166 publications

References 61 publications

Photoreduction and Stabilization Capability of Molecular Weight Fractionated Natural Organic Matter in Transformation of Silver Ion to Metallic Nanoparticle

Photoreduction and Stabilization Capability of Molecular Weight Fractionated Natural Organic Matter in Transformation of Silver Ion to Metallic Nanoparticle

Antibacterial activity of silver nanoparticles: A surface science insight

Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles

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