![](/client/images/blank.gif)
Eylem Seç
![Effect of Environmental Factors on the Aggregation Behavior of Silver Nanoparticles in the Aquatic Environment için kapak resmi Effect of Environmental Factors on the Aggregation Behavior of Silver Nanoparticles in the Aquatic Environment için kapak resmi](/client/assets/d79c3e4af2b6d196/ctx/images/no_image.png)
Effect of Environmental Factors on the Aggregation Behavior of Silver Nanoparticles in the Aquatic Environment
Başlık:
Effect of Environmental Factors on the Aggregation Behavior of Silver Nanoparticles in the Aquatic Environment
Yazar:
Afshinnia, Kamelia, author.
ISBN:
9780438112247
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (172 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Advisors: Mohammed Baalousha Committee members: Alan W. Decho; John Ferry; Jamie R. Lead.
Özet:
Understanding the environmental factors that impact the fate and effects of engineered nanoparticles (ENPs) in the environment is crucial for NP risk assessment. Silver nanoparticles (Ag NPs) readily transform in the environment, which alters their properties and subsequently their transport, fate, and toxicity. The overall aim of this dissertation was to evaluate the effects of Ag NPs physicochemical properties (e.g., size, surface charge, surface coating) and water chemistry (e.g., buffer concentration, organic ligands, natural organic matter) in controlling Ag NPs colloidal stability. This aim was achieved by systematically 1) review and rationalize the many studies that investigated the aggregation kinetics of Ag NPs; and 2) investigate the aggregation kinetics of Ag NPs under specific conditions that has not been studied in the literature, in particular presence of organic ligands with different structures, natural organic matter, and phosphate buffer concentration.
The critical coagulation concentration (CCC) is independent of NP concentration for pure electrostatic interactions. However, in the presence of chemical constituents of high affinity to NPs such as cystine, carbonate, and phosphate anions, the CCC is NP concentration-dependent. Although sterically stabilized Ag NPs do not aggregate even at high ionic strength; they are prone to destabilization following surface coating replacement by molecules with higher affinity to Ag NPs that do not provide steric stabilization. For instance, sterically stabilized polyvinylpyrrolidone (PVP) Ag NPs remained colloidally stable at high Na+ and Ca2+ concentrations, but the presence of cystine destabilized PVP Ag NPs at similar Na+ and Ca 2+ concentrations.
The molecular structure of organic ligands play a significant role in determining the stability of Ag NPs. L-cysteine (L-cys) decreases the stability of Ag NPs, whereas N-acetyl-L-cysteine (NAL-cys) increases the stability of Ag NPs. Whereas Suwanee River fulvic acid (SRFA) increased the stability of Ag NPs, addition of a mixture of SRFA and L-cysteine decreased the stability of Ag NPs. Cystine significantly impacts the stability of citrate, PVP, and polyethylene glycol (PEG) coated Ag NPs, resulting in a concentration-dependent aggregation of Ag NPs, with a shift in the CCC toward lower concentrations of cystine at lower concentrations of Ag NPs. Furthermore, the CCC for Ag NPs decreased with the increase in phosphate buffer concentration in the presence and absence of SRFA.
The majority of NP aggregation studies have focused on the effect of counter ions on NP aggregation kinetics, typically at environmentally irrelevant, high NP concentrations. This PhD focused on the impact of the less studied, yet equally important, environmental factors such as buffers, anions, organic ligands with different structures and properties (e.g., L-cys, NAL-cys and cystine) on Ag NP stability, especially at environmentally relevant NP concentrations. The findings of this PhD are important to underpin NP risk assessment and environmental fate and behavior studies.
Notlar:
School code: 0202
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(688925.1) | 688925-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.