Control of the growth processes of the silica sols colloidal particles

Hayrapetyan, Sergey S.; Khachatryan, H. G.

doi:10.1016/j.micromeso.2004.10.011

Cited by 9 publications

(5 citation statements)

References 12 publications

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“…For silica particles (e.g. used as stationary phase support in packed HPLC columns) are reported to be in the range 50-670 m 2 per gram of porous material, [25][26][27] which are similar to the values measured for porous silicon, which are in the range 80-340 m 2 per gram of porous material (see ESI †).…”

Section: Resultssupporting

confidence: 70%

Characterization of porous silicon integrated in liquid chromatography chips

et al. 2009

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Properties of porous silicon which are relevant for use of the material as a stationary phase in liquid chromatography chips, like porosity, pore size and specific surface area, were determined with high-resolution SEM and N(2) adsorption-desorption isotherms. For the anodization conditions investigated, porosity is between 20 and 60%, pore sizes between 2 and 5 nm and specific surface area between 130 and 410 m(2)/cm(3). It was established that under identical anodization conditions, porous layer formation is 10-15% slower on micromachined pillars than on flat substrates, and depends on geometrical parameters like pillar diameter and height and interpillar spacing. In microchannels containing pillars with a porous silicon shell, chromatographic experiments on a coumarin dye mixture were performed, which in comparison with non-porous pillars showed a significant increase of the retention factors, resulting from the large internal surface of the porous pillars. The increased relative retention of one of the coumarin dyes, C480, could be correlated quantitatively with the measured internal surface of the porous layer. Due to the small pore size, these porous shell columns are particularly suitable for analytical or preparative separation of low-molecular weight molecules, with applications in metabolomics, food quality control, or medical diagnostics.

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Section: Resultssupporting

confidence: 70%

Characterization of porous silicon integrated in liquid chromatography chips

et al. 2009

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“…As it can be seen from Eq. (1), the monomer molecule and preci-pitated SiO 2 in the polymerization process are obtained [9]. Anhydrous amorphous SiO 2 precipitates from the somewhat oversaturated monomer solutions, especially at high temperatures and neutral or alkaline pH values.…”

Section: -mentioning

confidence: 98%

The effects of colloidal SiO2 and inhibitor on the solid deposit formation in geothermal water of low hardness

Stankovic¹,

Randjelovic²,

Purenović³

2011

Hem Ind

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Low solubility of SiO2 and its occurrence in geothermal waters in the form of ionic, colloidal and suspended state are the main cause of the solid deposit occurrence. Certain chemical types of silica, under the influence of Fe2+, Al3+, F−, OH- ions and other micro-constituents, and due to significantly decreased solubility of SiO2, stimulate nucleation, particle growth and solid deposit formation. The aim of this paper is to inhibit the process of nucleation and solid deposit formation by adding originally designed inhibitor in the form of an emulsion, when the total concentration of the present and added colloidal SiO2 is beyond the solubility limit (120 mg/dm3). By turbidimetric, SEM, EDS and XRD analysis, the processes of solid deposit formation were investigated in Vranjska Banja (Serbia) spa geothermal water source (water hardness of 4ºdH), and theoretical and practical conclusions were made

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“…These discrete particles have hydroxylated surfaces and achieve stability by possessing a net negative charge on the surface, strong enough to repulse the van der Waals attractive forces. If different ions are introduced to the sol, this surface charge can be altered and can lead to agglomeration and gelation of the NS [30,31,32,33,34]. Therefore, adding well-dispersed NS to the concrete mixture can lead to agglomeration and gelation resulting from the release of ions during cement hydration.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Colloidal Nanosilica in an Ultrahigh Performance Concrete Environment Using Dynamic Light Scattering

2019

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The dispersion quality of nanosilica (NS) is an essential parameter to influence and control the material characteristics of nanosilica-enhanced concrete. In this research, the dispersion quality of colloidal nanosilica in simulated concrete environments was investigated using dynamic light scattering. A concrete environment was simulated by creating a synthetic pore solution that mimicked the ionic concentration and pH value of ultrahigh-performance concrete in the fluid state. Four colloidal nanosilica samples were used, ranging in particle sizes from 5 to 75 nm, with differing solid contents and stabilizing ions. It was found that the sodium stabilized 20 nm NS sol remains dispersed at a solid concentration of 2 wt % through a variety of pH values with the inclusion of potassium ions. Calcium ions are a major contributor to the agglomeration of NS sols and only small concentrations of calcium ions can drastically affect the dispersion quality.

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Control of the growth processes of the silica sols colloidal particles

Cited by 9 publications

References 12 publications

Characterization of porous silicon integrated in liquid chromatography chips

Characterization of porous silicon integrated in liquid chromatography chips

The effects of colloidal SiO2 and inhibitor on the solid deposit formation in geothermal water of low hardness

Behavior of Colloidal Nanosilica in an Ultrahigh Performance Concrete Environment Using Dynamic Light Scattering

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