Impact of light and Suwanee River Fulvic Acid on O2 and H2O2 Mediated Oxidation of Silver Nanoparticles in Simulated Natural Waters

2019 ◽  
Vol 53 (12) ◽  
pp. 6688-6698 ◽  
Author(s):  
Hongyan Rong ◽  
Shikha Garg ◽  
T. David Waite
Keyword(s):  
Silver Nanoparticles ◽  
Fulvic Acid ◽  
Natural Waters ◽  
Mediated Oxidation

Heavy Metal Binding Components of River Water

1975 ◽  
Vol 32 (10) ◽  
pp. 1755-1766 ◽  
Author(s):  
S. Ramamoorthy ◽  
D. J. Kushner
Keyword(s):  
Heavy Metal ◽  
Fulvic Acid ◽  
River Water ◽  
Metal Binding ◽  
Natural Waters ◽  
Binding Capacity ◽  
Binding Constants ◽  
Binding Ability ◽  
Ottawa River ◽  
Almost All

Ion-specific electrodes were used to measure the heavy metal (HM) binding capacity of river waters near Ottawa. Binding capacity was measured in unfiltered water and in water passed through filters retaining particles (0.45 μm) and macromolecules of molecular weight (MW) 45,000, 16,000 and 1,400. In the most studied water samples, almost all the Hg2+-binding ability passed through the smallest filter. Filters of different pore sizes retained substantial fractions of the binding ability towards other HM ions. Binding strengths and conditional binding constants were calculated for each HM ion and low MW Ottawa River water components.Binding in Ottawa River water was not due to HCO3− or CO32− ions; in the Rideau Canal, and probably in other bodies of water, such ions caused a substantial amount of binding. After complete ashing of Ottawa River water and reconstitution with deionized water almost all the HM binding ability was lost; thus, an organic compound(s) is responsible for binding.The binding pattern towards different HM ions of fulvic acid isolated from soil was different from that of unfiltered or filtered Ottawa River water. Fulvic acid is not the sole binding component of this water. These experiments suggest a way of assessing the importance of fulvic acid and other humic substances in HM binding by natural waters.

scholarly journals Heteroagglomeration of nanosilver with colloidal SiO2 and clay

2017 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Sébastien Maillette ◽  
Caroline Peyrot ◽  
Tapas Purkait ◽  
Muhammad Iqbal ◽  
Jonathan G. C. Veinot ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Polyacrylic Acid ◽  
Natural Waters ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Analytical Techniques ◽  
Dark Field ◽  
Correlation Spectroscopy ◽  
Colloidal Clay ◽  
High Concentrations

Environmental contextThe fate of nanomaterials in the environment is related to their colloidal stability. Although numerous studies have examined their homoagglomeration, their low concentration and the presence of high concentrations of natural particles implies that heteroagglomeration rather than homoagglomeration is likely to occur under natural conditions. In this paper, two state-of-the art analytical techniques were used to identify the conditions under which nanosilver was most likely to form heteroagglomerates in natural waters. AbstractThe environmental risk of nanomaterials will depend on their persistence, mobility, toxicity and bioaccumulation. Each of these parameters is related to their fate (especially dissolution, agglomeration). The goal of this paper was to understand the heteroagglomeration of silver nanoparticles in natural waters. Two small silver nanoparticles (nAg, ~3nm; polyacrylic acid- and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO2, ~18.5nm) or clays (~550nm SWy-2 montmorillonite). Homo- and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50μg Ag L–1; pH 7.0; ionic strength 10–7 to 10–1 M Ca) by following the sizes of the nAg by fluorescence correlation spectroscopy. The polyacrylic acid-coated nanosilver was extremely stable under all conditions, including in the presence of other colloids and at high ionic strengths. However, the citrate-coated nanosilver formed heteroaggregates in presence of both colloidal SiO2 and clay particles. Nanoparticle surface properties appeared to play a key role in controlling the physicochemical stability of the nAg. For example, the polyacrylic acid stabilized nAg-remained extremely stable in the water column, even under conditions for which surrounding colloidal particles were agglomerating. Finally, enhanced dark-field microscopy was then used to further characterise the heteroagglomeration of a citrate-coated nAg with suspensions of colloidal clay, colloidal SiO2 or natural (river) water.

Monitoring the Fate and Transformation of Silver Nanoparticles in Natural Waters

2016 ◽  
Vol 97 (4) ◽  
pp. 449-455 ◽  
Author(s):  
Lindsay M. Furtado ◽  
Mirco Bundschuh ◽  
Chris D. Metcalfe
Keyword(s):  
Silver Nanoparticles ◽  
Natural Waters

Effects of silver nanoparticles on bacterial activity in natural waters

2011 ◽  
Vol 31 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Pranab Das ◽  
Marguerite A. Xenopoulos ◽  
Clayton J. Williams ◽  
Md Ehsanul Hoque ◽  
Chris D. Metcalfe
Keyword(s):  
Silver Nanoparticles ◽  
Natural Waters ◽  
Bacterial Activity

Sensitized Photooxidation of Phenols by Fulvic Acid and in Natural Waters

1987 ◽  
Vol 21 (10) ◽  
pp. 957-964 ◽  
Author(s):  
Bruce C. Faust ◽  
Jurg. Hoigne
Keyword(s):  
Fulvic Acid ◽  
Natural Waters

The persistence and transformation of silver nanoparticles in littoral lake mesocosms monitored using various analytical techniques

2014 ◽  
Vol 11 (4) ◽  
pp. 419 ◽  
Author(s):  
Lindsay M. Furtado ◽  
Md Ehsanul Hoque ◽  
Denise M. Mitrano ◽  
James F. Ranville ◽  
Beth Cheever ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Waters ◽  
Lake Water ◽  
Natural Waters ◽  
Municipal Wastewater ◽  
Analytical Techniques ◽  
Aquatic Organisms ◽  
Silver Ions ◽  
Icp Ms ◽  
The Individual

Environmental context Silver nanoparticles discharged with municipal wastewater may contaminate surface waters and harm aquatic ecosystems. We applied several analytical techniques to investigate the persistence and transformation of silver nanoparticles in a natural lake environment, and show, through multiple lines of evidence, that they persisted in lake water for several weeks after addition. The nanoparticles were releasing silver ions through dissolution, but these toxic ions were likely binding with natural organic matter in the lake water. Abstract Silver nanoparticles (AgNPs) may be released into surface waters, where they can affect aquatic organisms. However, agglomeration, dissolution, surface modifications and chemical speciation are important processes that control the toxicity of AgNPs. The purpose of the study was to apply various methods for monitoring the persistence and transformation of AgNPs added to littoral lake mesocosms. Analysis of total Ag showed that the levels in the mesocosms declined rapidly in the first 12h after addition, followed by a slower rate of dissipation with a half-life (t1/2) of ~20 days. Analysis using single particle ICP-MS (spICP-MS) showed no evidence of extensive homo-agglomeration of AgNPs. The stability of AgNPs was likely due to the low ionic strength and high concentrations of humic-rich dissolved organic carbon (DOC) in the lake water. Analyses by spICP-MS, cloud point extraction (CPE) and asymmetric flow field flow fractionation coupled to ICP-MS (AF4-ICP-MS) all indicated that the concentrations of AgNP decreased over time, and the nanoparticles underwent dissolution. However, the concentrations of dissolved silver, which includes Ag+, were generally below detection limits when analysed by centrifugal ultrafiltration and spICP-MS. It is likely that the majority of free ions released by dissolution were complexing with natural organic material, such as DOC. An association with DOC would be expected to reduce the toxicity of Ag+ in natural waters. Overall, we were able to characterise AgNP transformations in natural waters at toxicologically relevant concentrations through the use of multiple analytical techniques that compensate for the limitations of the individual methods.

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