Aggregation of manufactured nanoparticles in aqueous solutions of mono- and bivalent electrolytes

Godymchuk, Anna; Karepina, Elizaveta; Yunda, Elena; Божко, И. А.; Lyamina, G. V.; Кузнецов, Денис; Gusev, Alexander; Kosova, Natalia I.

doi:10.1007/s11051-015-3012-7

Cited by 9 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, increasing the ionic strength of the electrolyte solution compresses the diffused layer associated with the NPs, resulting in lowered ζ potential on the surfaces and diminished repulsions between NPs, and therefore, promoting particle aggregation. Similar observation was also made for several metal oxide NPs, including γ-Al 2 O 3 [ 49 ], magnetite (Fe 3 O 4 ) [ 36 ], TiO 2 [ 50 , 51 ], and cerium oxide (CeO 2 ) [ 52 ]. Thus, the presence of Na + and Ca 2+ will have a significant impact on the particle surface charges and thereby, particle aggregation, in natural waters where pH is lower than PZC.…”

Section: Resultssupporting

confidence: 68%

Aggregation and Colloidal Stability of Commercially Available Al2O3 Nanoparticles in Aqueous Environments

2016

View full text Add to dashboard Cite

The aggregation and colloidal stability of three, commercially-available, gamma-aluminum oxide nanoparticles (γ-Al2O3 NPs) (nominally 5, 10, and 20–30 nm) were systematically examined as a function of pH, ionic strength, humic acid (HA) or clay minerals (e.g., montmorillonite) concentration using dynamic light scattering and transmission electron microscopy techniques. NPs possess pH-dependent surface charges, with a point of zero charge (PZC) of pH 7.5 to 8. When pH < PZC, γ-Al2O3 NPs are colloidally stable up to 100 mM NaCl and 30 mM CaCl2. However, significant aggregation of NPs is pronounced in both electrolytes at high ionic strength. In mixed systems, both HA and montmorillonite enhance NP colloidal stability through electrostatic interactions and steric hindrance when pH ≤ PZC, whereas their surface interactions are quite limited when pH > PZC. Even when pH approximates PZC, NPs became stable at a HA concentration of 1 mg·L−1. The magnitude of interactions and dominant sites of interaction (basal planes versus edge sites) are significantly dependent on pH because both NPs and montmorillonite have pH-dependent (conditional) surface charges. Thus, solution pH, ionic strength, and the presence of natural colloids greatly modify the surface conditions of commercial γ-Al2O3 NPs, affecting aggregation and colloidal stability significantly in the aqueous environment.

show abstract

Section: Resultssupporting

confidence: 68%

Aggregation and Colloidal Stability of Commercially Available Al2O3 Nanoparticles in Aqueous Environments

2016

View full text Add to dashboard Cite

show abstract

“…The processes of aggregation and “complex” formation of NPs with polyelectrolytes have been widely studied using experimental methods, ,,,− theoretical, − and numerical models − by considering physicochemical properties of solution and nanoparticles. The surface charge is one of the most important parameter in these processes and can be modeled using Monte Carlo simulations, , the Poisson–Boltzmann approximation, or an Ising model .…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface and Salt Properties on the Ion Distribution around Spherical Nanoparticles: Monte Carlo Simulations

2016

View full text Add to dashboard Cite

Nanoparticle surface charge properties represent key parameters to predict their fate, reactivity, and complexation in natural, biological, and industrial dispersions. In this context, we present here an original approach to better understand the surface charge electrostatic properties of spherical nanoparticles (NPs). The ion distribution around one nanoparticle is investigated using Monte Carlo simulations and by adjusting a wide range of parameters including NP properties (surface charge density and site distribution), salt concentration (ionic strength and cation concentration), and salt valency (mono-, di-, and trivalent salt). A canonical Metropolis Monte Carlo method is used to reach equilibrium states and a primitive Coulomb model is applied to describe the electrostatic interactions between explicit discrete sites, counterions, and salt particles. Our results show that the presence of explicit surface charges on the NP and in solution has a strong influence on the local ion distribution and on the effective surface charge of the nanoparticles. The increase of surface charge density reduces the NP effective charge by the formation of a condensation layer around the nanoparticle. However, a limit of condensation is achieved due to steric effects and electrostatic repulsions. The presence of di- and trivalent cations is also found to strongly modify the effective charge and improve condensation state as long as electrostatic repulsion between the cations close to the surface are not so strong. At high trivalent cation concentration, the NP effective charge is greatly reduced and the local environment around the nanoparticle becomes more structured with the formation of a multi layer structure composed by anions and cations.

show abstract

“…Among the undoubted advantages of such chemosensors, one should note the ease of fixing the analytical response, high sensitivity, and the possibility of fine tuning the optical and analytical characteristics. At the same time, they have several disadvantages, in particular, the aggregative instability of nanoparticles, which can be caused by a high ionic strength or the presence of substances that are specifically adsorbed on nanoparticles and destabilize them [ 34 , 35 , 36 , 37 ]. One of the widely used approaches to solving this problem is the complex modification of nanoparticles but this leads to a significant increase in the cost of analysis.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Reactive Indicator Papers Based on Silver-Containing Nanocomposites for the Analysis of Chloride Ions

Gorbunova,

Uflyand,

Zhinzhilo

et al. 2023

Micromachines

View full text Add to dashboard Cite

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In this work, for the first time, a detailed analysis of the preparation of reactive indicator papers (RIPs) based on silver-containing nanocomposites derived from silver fumarate was carried out. Thermolysis products are silver-containing nanocomposites containing silver nanoparticles uniformly distributed in a stabilizing carbon matrix. The study of the optical properties of silver-containing nanocomposites made it possible to outline the prospects for their application in chemical analysis. RIPs were made by impregnating a cellulose carrier with synthesized silver fumarate-derived nanocomposites, which change their color when interacting with chlorine vapor. This made it possible to propose a method for the determination of chloride ions with preliminary oxidation to molecular chlorine, which is then separated from the solution by gas extraction. The subsequent detection of the active zone of RIPs using colorimetry makes it possible to identify mathematical dependences of color coordinates on the concentration of chloride ions. The red (R) color coordinate in the RGB (red-green-blue) system was chosen as the most sensitive and promising analytical signal. Calibration plots of exponential and linear form and their equations are presented. The limit of detection is 0.036 mg/L, the limits of quantification are 0.15–2.4 mg/L, and the time of a single determination is 25 min. The prospects of the developed technique have been successfully shown in the example of the analysis of the natural waters of the Don River, pharmaceuticals, and food products.

show abstract

Aggregation of manufactured nanoparticles in aqueous solutions of mono- and bivalent electrolytes

Cited by 9 publications

References 24 publications

Aggregation and Colloidal Stability of Commercially Available Al2O3 Nanoparticles in Aqueous Environments

Aggregation and Colloidal Stability of Commercially Available Al2O3 Nanoparticles in Aqueous Environments

Effect of Surface and Salt Properties on the Ion Distribution around Spherical Nanoparticles: Monte Carlo Simulations

Preparation of Reactive Indicator Papers Based on Silver-Containing Nanocomposites for the Analysis of Chloride Ions

Contact Info

Product

Resources

About