Effect of pH and Salt on Rheological Properties of Aerosil Suspensions

Chen, Shukun; Øye, Gisle; Sjöblom, Johan

doi:10.1080/01932690701345844

Cited by 33 publications

(33 citation statements)

References 27 publications

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“…For the particular system of silica, some authors [2,6,7,9] have noticed an abnormal stability at low pH values near the isoelectric point, which contrasts with that predicted by the classical DLVO theory. This means that there exists another repulsive short-range force that is not considered in the theory.…”

Section: Introductionmentioning

confidence: 46%

“…Figure 4 a) shows how the zeta potential increases in the negative sense when increasing the pH value. When the pH is raised above the isoelectric point (pH = 2), the surface charge of the nanoparticles is increased and as a result the absolute value of the zeta potential also increases [6,7,9,19].…”

Section: Zeta Potential ψmentioning

confidence: 99%

“…This velocity is measured using Laser Doppler Velocimetry (LDV) and the zeta potential is obtained through the Henry equation [7].…”

Section: Zeta Potential ψmentioning

confidence: 99%

“…To make stable dispersions it is necessary to disperse the large agglomerates that form the initial dry powder into primary particles. The equipment used to disperse nanoparticles includes ultrasonic bath [5][6][7][8][9], ultrasonic probe [10][11][12], magnetic stirrer, high-shear mixer [13], homogenizer and ball mill. Both the processing time and the energy influence the dispersion effect.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of silica–water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability

et al. 2012

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of silica-water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability. Powder Technology, 2012, Vol. 224 AbstractThe stability and agglomeration state of nanofluids are key parameters for their use in different applications. Silica nanofluids were prepared by dispersing the nanoparticles in distilled water using an ultrasonic probe, which has proved to be the most effective system and gives the best results when compared with previous works. Results were obtained concerning the influence of the solid content, pH and salt concentration on the zeta potential, electrical double layer, viscosity, elastic and viscous moduli, particle size and light backscattering. Measurement of all these properties provides information about the colloidal state of nanofluids. The most important variable is the solid content.Despite the agglomeration due to high concentration, nanofluids with low viscosity and behaving like liquid were prepared at 20% of mass load thanks to the good dispersion achieved with the ultrasonic treatment. The pH of the medium can be used to control the stability, since the nanofluids are more stable under basic conditions far from the isoelectric point (IEP) and settle at pH = 2. Therefore, stable nanofluids for at least 48 h, with high solid content, can be prepared at high pH value (pH > 7) due to the electrostatic repulsion between particles.

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Section: Introductionmentioning

confidence: 46%

Section: Zeta Potential ψmentioning

confidence: 99%

“…This velocity is measured using Laser Doppler Velocimetry (LDV) and the zeta potential is obtained through the Henry equation [7].…”

Section: Zeta Potential ψmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of silica–water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability

et al. 2012

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“…Quartz exhibits a negative surface charge over the entire pH range never attaining the point of zero charge, as reported in the literature. 24 The shape of the ζ-potential curve is different from that of amorphous silicas 25,26 and pure crystalline silica, 27 likely because of metal contaminants in the pristine quartz. Carbon soot exhibits a negative surface charge only above pH 3, while from pH 0 to 12 3 is positively charged, being less acidic than quartz.…”

Section: Particle Morphologymentioning

confidence: 99%

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Ghiazza

Tomatis

Doublier

et al. 2012

Chem. Res. Toxicol.

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In order to evaluate the effect of carbonaceous materials on the pathogenic activity of quartz dusts, mixtures of carbon soot (1% and 10%) and quartz (Min-U-Sil ) have been prepared, then milled so to attain an intimate association of carbon and the quartz surface. Both cellular and cell-free tests show that carbon associated to quartz completely inhibits the typical free radical generation of quartz dusts (through Fenton activity and homolytic cleavage of a C-H bond) and suppresses the oxidative stress and inflammation induced by quartz alone on MH-S murine macrophage cells (lipid peroxidation, nitric oxide release, tumour necrosis factor-α synthesis). Cytotoxic response to quartz is also largely reduced. An extremely pure quartz milled with 10% of soot showed inactivating effects on the adverse reactions to quartz similar to Min-U-Sil quartz. None of these effects takes place when the same experiments are carried out with mechanically mixed samples, which suggests that carbon acts not just as a radical quencher, but because of its association to the quartz surface.4

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Nanotechnology and Nanomaterials for Thermal Energy Storage

Mondragón

Martínez‐Cuenca

Hernández

et al. 2015

Handbook of Clean Energy Systems

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Thermal energy storage is a key technology in order to optimize the performance of industrial systems such as concentrating solar power plants and heat insulation in buildings. This technology can be combined with the development of new materials with enhanced thermal properties thanks to the addition of nanoparticles to a conventional material. The new materials, generally referred to as nanocomposites and nanofluids , are produced by specific procedures in order to ensure their stability over time. The main results that have been published on the enhancement of thermal properties and energy storage through sensible heat storage and phase change materials are summarized.

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Effect of pH and Salt on Rheological Properties of Aerosil Suspensions

Cited by 33 publications

References 27 publications

Characterization of silica–water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability

Characterization of silica–water nanofluids dispersed with an ultrasound probe: A study of their physical properties and stability

Carbon in Intimate Contact with Quartz Reduces the Biological Activity of Crystalline Silica Dusts

Nanotechnology and Nanomaterials for Thermal Energy Storage

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