Effects of molecular weight-fractionated natural organic matter on the phytoavailability of silver nanoparticles

2018 ◽  
Vol 5 (4) ◽  
pp. 969-979 ◽  
Author(s):  
Min Li ◽  
Fei Dang ◽  
Qing-Long Fu ◽  
Dong-Mei Zhou ◽  
Bin Yin
Keyword(s):  
Molecular Weight ◽  
Silver Nanoparticles ◽  
Organic Matter ◽  
Natural Organic Matter

The key role of NOM heterogeneity in inhibiting the dissolution and consequently the uptake of total Ag.

Effects of hydrophobicity-based fractions of Pony Lake fulvic acid on the colloidal stability and dissolution of oppositely charged surface-coated silver nanoparticles

2020 ◽  
Vol 17 (5) ◽  
pp. 400 ◽  
Author(s):  
YounJung Jung ◽  
Gabriele E. Schaumann ◽  
Seungyun Baik ◽  
George Metreveli
Keyword(s):  
Molecular Weight ◽  
Silver Nanoparticles ◽  
Organic Matter ◽  
Fulvic Acid ◽  
Functional Groups ◽  
Natural Organic Matter ◽  
Colloidal Stability ◽  
Coating Materials ◽  
Polar Functional Groups ◽  
Oppositely Charged

Environmental contextThe fate of silver nanoparticles (AgNPs) in aqueous systems could be influenced by the hydrophobicity of natural organic matter. We observed that the aggregation and dissolution of oppositely charged AgNPs were controlled by the selectivity and dynamics of sorption processes involving the nanoparticle surface and hydrophobic groups on natural organic matter. These findings will be helpful to understand the fate and effects of coated AgNPs in natural systems. AbstractThe fate of silver nanoparticles (AgNPs) released into aquatic environments is significantly affected by natural organic matter (NOM). However, current studies are still insufficient to understand interactions between NOM and AgNPs because they do not explicitly consider the heterogeneity of NOM. We investigated how NOM components with different properties (hydrophobicity, molecular weight, aromaticity, and polarity of functional groups) interact with AgNPs coated with citrate (Cit) and branched polyethylenimine (BPEI) and influence their colloidal stability and dissolution. Pony Lake fulvic acid (PLFA) selected as a model NOM was fractionated into hydrophobic (HPO) and transphilic (TPI) fractions. Sorption of PLFA molecules with a high content of polar functional groups bound to the aromatic rings onto nanoparticles was more favourable in the case of the TPI fraction, which most likely resulted in higher aggregation for both AgNPs and stronger protection of BPEI-AgNPs against dissolution compared with the HPO fraction. Additionally, in contrast to the Cit-AgNPs, resorption of Ag+ ions released from BPEI-AgNPs and/or sorption of Ag+-PLFA complexes to the nanoparticles was most likely a dynamic process, as suggested by the time-dependent changes in the molecular weight of the PLFA fractions sorbed to the BPEI-AgNP surface. These observations suggest that the accessibility of the AgNP surface for the hydrophobicity-based fractions of NOM as well as their colloidal stability and dissolution are controlled by the type and charge of coating materials and by the molecular weight, aromaticity, and content of polar functional groups of NOM.

Advanced oxidation processes: flowsheet options for bulk natural organic matter removal

2004 ◽  
Vol 4 (4) ◽  
pp. 113-119 ◽  
Author(s):  
C.A. Murray ◽  
S.A. Parsons
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Natural Organic Matter ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Oxidation Processes

Advanced oxidation processes have been reported to have the potential to remove natural organic matter from source waters. Of these Fenton's reagent, photo-Fenton's reagent and titanium dioxide photocatalysis are the three most promising processes. Compared to conventional coagulation/flocculation processes they have higher removal efficiencies in terms of both dissolved organic carbon and UV254 absorbance. Under optimum reaction conditions all three remove over 80% dissolved organic carbon and 0% UV254 absorbance. In addition the enhanced removal of natural organic matter leads to a corresponding reduction in the formation of disinfection by-products following chlorination of the treated water. Advanced oxidation processes give enhanced removal of organic species ranging from low to high molecular weight while coagulation/flocculation is inefficient at removing low molecular weight species. One additional benefit is all three processes produce less residuals compared to conventional coagulation, which is advantageous as the disposal of such residuals normally contributes a large proportion of the costs at water treatment works.

scholarly journals Aging reduces the toxicity of pristine but not sulphidised silver nanoparticles to soil bacteria

2018 ◽  
Vol 5 (11) ◽  
pp. 2618-2630 ◽  
Author(s):  
Carolin L. Schultz ◽  
Joanna Gray ◽  
Rudo A. Verweij ◽  
Martí Busquets-Fité ◽  
Victor Puntes ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Soil Bacteria

Aging of silver nanoparticles shows soluble silver driving toxicity in ISO medium, but not in media containing natural organic matter.

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