Humic Acid-Induced Silver Nanoparticle Formation Under Environmentally Relevant Conditions

Akaighe, Nelson; MacCuspie, Robert I.; Navarro, Divina A.; Aga, Diana S.; Banerjee, Sarbajit; Sohn, Mary; Sharma, Virender K.

doi:10.1021/es103946g

Cited by 278 publications

(217 citation statements)

References 30 publications

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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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Section: Fate Of Silver Nanoparticles In the Environmentmentioning

confidence: 99%

Antibacterial activity of silver nanoparticles: A surface science insight

2015

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“…From equation (16), k 0 was estimated to be 7 -1 -1 (5.2 0.1) 10 g s ± × (the kinetic rate was calculated using the weight of Ag/AgCl @ chiral TiO 2 nanofibers as its molecular…”

Section: Evaluation Of Kinetic Ratesmentioning

confidence: 99%

“…However, the application of such new photoactive material for the removal of contaminants in wastewater and drinking water needs to be demonstrated. This is of significance as (i) the influence of water matrix components on the generation of ROS is complex and will finally affect the photocatalytic performance of Ag/AgCl [14][15][16], and (ii) Ag nanoparticles (AgNPs) and silver ions (Ag + ) which may be released into the wastewater and drinking water can potentially induce antibacterial and antiviral impacts [17]. Preliminary studies have been conducted to understand the impacts of different water components on the dissolution, transformation and transportation of AgNPs.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and experimental study on the photocatalytic performance of Ag/AgCl @ chiral TiO2 nanofibers photocatalyst: The impact of wastewater components

Wang

Puma

et al. 2015

Journal of Hazardous Materials

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“…AgNPs present in the environment are normally thought to originate from human activities. However, recent studies reveal that AgNPs can also form naturally via the reduction of Ag + in natural waters mediated by dissolved organic matter (DOM) 7,8 and sunlight 9 , which implies that the level of AgNPs in the environment may be underestimated. There is evidence that AgNPs are potentially harmful for organisms and human health 1 and that AgNP loading can significantly influence important ecosystem processes 10,11 .…”

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confidence: 99%

Stable silver isotope fractionation in the natural transformation process of silver nanoparticles

et al. 2016

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Nanoparticles in the environment can form by natural processes or be released due to human activities 1 . Owing to limited analytical methods, the behaviour of nanoparticles in the natural environment is poorly understood and until now they have only been described by the variations in the nanoparticle size or the concentration of the element of interest. Here we show that by using inductively coupled plasma mass spectrometry to measure silver (Ag) isotope ratios it is possible to understand the transformation processes of silver nanoparticles (AgNPs) in the environment. We found that the formation and dissolution of AgNPs under natural conditions caused significant variations in the ratio of natural Ag isotopes ( 107 Ag and 109 Ag) with an isotopic enrichment factor (ε) up to 0.86‰. Furthermore, we show that engineered AgNPs have distinctly different isotope fractionation effects to their naturally formed counterparts. Further studies will be needed to understand whether isotope analysis can be used to reveal the sources of AgNPs in the environment.AgNPs are the most widely used nanomaterial due to their broad spectrum in antimicrobial activities 2 . An exponential increase in the environmental levels of AgNPs is predicted due to their rising usage and disposal levels 3,4 . As the natural abundance of Ag in the Earth's crust is extremely low (∼0.07 mg kg -1 ; ref. 5), the release of even a small mass of Ag to the environment from anthropogenic activities may lead to proportionally large deviations from natural conditions 6 . AgNPs present in the environment are normally thought to originate from human activities. However, recent studies reveal that AgNPs can also form naturally via the reduction of Ag + in natural waters mediated by dissolved organic matter (DOM) 7,8 and sunlight 9 , which implies that the level of AgNPs in the environment may be underestimated. There is evidence that AgNPs are potentially harmful for organisms and human health 1 and that AgNP loading can significantly influence important ecosystem processes 10,11 . However, little is known about the natural processes and fate of AgNPs due to the lack of proper methods to detect or trace AgNPs in environmental media.Here, we studied the variations in the stable Ag isotope ratio in the natural transformation process of AgNPs. Ag isotopes have previously been applied as chronometers for early-stage planetary differentiation 12,13 and as tracers in archaeometry 14,15 , whereas other applications are rare in the literature. Naturally occurring Ag is composed of 107 Ag and 109 Ag with approximately equal natural abundances (51.8% versus 48.2%) and subtle variations in 107 Ag/ 109 Ag ratio were observed in various terrestrial samples 16,17 . We hypothesized that variations in the natural stable isotope ratio may provide a new means to study the environmental processes of NPs. To test this hypothesis, we studied two reversible processes of AgNPs in natural waters (Fig. 1): the formation of AgNPs via the reduction of Ag + in the presence of DOM and the...

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Humic Acid-Induced Silver Nanoparticle Formation Under Environmentally Relevant Conditions

Cited by 278 publications

References 30 publications

Antibacterial activity of silver nanoparticles: A surface science insight

Antibacterial activity of silver nanoparticles: A surface science insight

Mechanism and experimental study on the photocatalytic performance of Ag/AgCl @ chiral TiO2 nanofibers photocatalyst: The impact of wastewater components

Stable silver isotope fractionation in the natural transformation process of silver nanoparticles

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