Yield stress and zeta potential of nanoparticulate silica dispersions under the influence of adsorbed hydrolysis products of metal ions—Cu(II), Al(III) and Th(IV)

Leong, Yee-Kwong

doi:10.1016/j.jcis.2005.06.004

Cited by 54 publications

(37 citation statements)

References 23 publications

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“…Some researchers have reported that polystyrene particle has the surface potential ψ of tens of millivolts [21][22][23] and the Hamaker constant A of about 1×10 −21 J. 23) For polystyrene, we pay attention to the curves (i) and (ii) in On the other hand, in the case of silica, it is known that the surface potential is several millivolts [24][25][26] Fig. 19(b).…”

Section: Discussionmentioning

confidence: 99%

Flow of Dilute Colloidal Dispersions in Water through a Small Orifice

Toga

Hasegawa

Narumi

2007

J. Soc. Rheol., Jpn

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Fluctuation of flows through a small orifice has been measured for water and two kinds of colloidal dispersions including fine particles about 100 nm in diameter with 1 % volume fraction in water. In this volume fraction, a surface potential of the particles is composed of an electrostatic repulsion and a van der Waals attraction and it affects flow properties. Experiments clarify that a specific flow instability occurs for water at the Reynolds number about 60, and the dispersion of polystyrene particles having strong repulsion increases the specific flow instability in low salt concentrations(LSC) but makes it disappear in high salt concentrations(HSC). Meanwhile, it is found that the dispersion of silica particles having strong attraction is stable in flows except the specific flow instability in LSC but it suppresses the specific flow instability in HSC as in the case of polystyrene particles. Criterion whether the orifice flow is stable or not is predicted by comparison of the second minimum location of the surface potential and the mean surfaces distance of the particles.

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Section: Discussionmentioning

confidence: 99%

Flow of Dilute Colloidal Dispersions in Water through a Small Orifice

Toga

Hasegawa

Narumi

2007

J. Soc. Rheol., Jpn

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“…Hydration shells hydrolyse with increasing pH, which may result in weakly soluble hydroxides and negatively charged hydroxide complex-ions (e.g. Leong 2005). Hence, the adsorption of ionic species and its effect on the net charge of surface and Stern layer is a function of pH.…”

Section: Adsorption Of Ions At Oxidic Surfacesmentioning

confidence: 99%

“…Figure 3.8 depicts the typical pH-dependency of the zeta-potential for colloidal suspensions in the presence hydrolysable metal ions. There are three points of charge reversal (PCR), which correspond to the PZC of the surface (PCR 1), to the neutralisation of the negative surface charge due to positively charged surface precipitate (PCR 2) and to the charge reversal of the hydroxide phase (James and Helay 1972;Leong 2005). The second and third PCR can only be observed for a sufficiently high concentration of the hydrolysable metal ions, i.e.…”

Section: Surface Precipitationmentioning

confidence: 99%

Fundamentals in Colloid Science

Babick

2016

Suspensions of Colloidal Particles and Aggregates

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Preparation and handling of colloidal suspension or even their characterisation is not possible without a basic understanding of the physical effects that prevail on the microscopic level. Some of these effects are directly related to the fineness of the particles because it coincides with a large specific surface area (which corresponds, e.g., to a high adsorption capacity), a considerably curvature of the particle surface (which i. a. promotes dissolution), a high number concentration (i.e. significant osmotic pressure and large collision frequencies), small interparticle distances (i.e. strong interactions between scattered waves), low particle mass (i.e. low weight and inertia), or with the fact that the wavelength of light is larger than particle size (i.e. weak optical scattering). A further effect of the small size of colloidal particles is that their diffusive motion is much faster than for micrometre particles. Moreover, the interactions between colloidal particles are decisive for the macroscopic behaviour of the whole suspension (e.g. with regard to rheology or coagulation). These interactions may be attractive and/or repulsive and depend on the chemical nature and the material properties of the particles. Most of all, they are affected by the interfacial properties which reflect the physico-chemical interaction between the particulate phase, the solvent, and the solutes (e.g. hydrophobicity, adsorption, surface charging).This chapter provides a brief introduction to the fundamentals in colloid science. It addresses the physico-chemical properties of single colloidal particles as well as the processes at the interface and the structure of the interfacial layer. It further examines the non-viscous interactions that occur among colloidal particles. For detailed explanation, the reader is referred to the textbooks of Adamson and Gast

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“…Adsorbed hydrolysis products may give rise to a range of interparticle forces in the slurry such as bridging, charged patch and enhanced van der Waals attraction (Leong, 2005). These forces have a significant effect on slurry rheology.…”

Section: Metal Ions Solubility and Hydrolysismentioning

confidence: 99%

“…Metal ions are known to form hydrolysis products at various pH levels (Baes and Mesmer, 1986). Hydrolysis products are known to adsorb readily (James and Healy, 1972a;Leong, 2005) and affect slurry rheology (Leong, 2005;Mpofu et al, 2003), electrokinetic properties (James and Healy, 1972a, b), coagulation rate (Matijevic et al, 1960;Matijevic and Janauer, 1966) and flotation recovery (Fuerstenau et al, 1965). In this study, the role of hydrolysis products on slurry properties will be examined.…”

Section: Introductionmentioning

confidence: 99%