Silica, the Three-dimensional Silicates, Borosilicates and Beryllium Silicates

Moenke, Horst

doi:10.1180/mono-4.16

Cited by 126 publications

(114 citation statements)

References 28 publications

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“…The band at 1015 cm -] is absent from the spectrum of the residue after complete dissolution of the hectorite (Figure 4, 8 hr). Further evidence for increased amorphous SiO 2 as acid dissolution progresses is also shown by the increase in intensity of the band at 798 cm -] attributed to the Si- (Moenke 1974). The IR spectra of dissolved hectorite residues also show a medium intensity band near 965 cm-1 (Figure 4, 8 hr) due to Si-O stretching of SiOH groups (Moenke 1974).…”

Section: Infrared Spectroscopymentioning

confidence: 75%

“…Further evidence for increased amorphous SiO 2 as acid dissolution progresses is also shown by the increase in intensity of the band at 798 cm -] attributed to the Si- (Moenke 1974). The IR spectra of dissolved hectorite residues also show a medium intensity band near 965 cm-1 (Figure 4, 8 hr) due to Si-O stretching of SiOH groups (Moenke 1974). The disappearance of the band at 657 cm -~, assigned to bending O-H vibrations of hectorite (Farmer 1974), and the presence of only a shoulder at 1016 cm -~ due to Si-O vibrations in the tetrahedral sheet indicate that most of the hectorite was dissolved within the first two h of the acid treatment ( The anion of the acid also affects the dissolution rate of hectorite.…”

Section: Infrared Spectroscopymentioning

confidence: 83%

“…The most prominent of these changes were shifts in the Si-O stretching region. The Si-O stretching band at 1015 cm -] diminished and the intensity of the Si-O absorption of amorphous SiO 2 near 1100 cm -~ (Moenke 1974) increased during the course of acid dissolution. The band at 1015 cm -] is absent from the spectrum of the residue after complete dissolution of the hectorite (Figure 4, 8 hr).…”

Section: Infrared Spectroscopymentioning

confidence: 99%

“…The intensity of the OH bending vibrations of hectorite near 650 cm ~, however, is too weak to use this criterion, but changes in the Si-O stretching region are more distinct and thus more useful for monitoring the dissolution of hectorite. The IR spectra of acid-dissolution residues from either hectorite (Figure 4, 8 hr) or montmorillonite ) have absorption bands with similar shapes and positions as a hydrous amorphous silica phase (Moenke 1974). …”

Section: Infrared Spectroscopymentioning

confidence: 99%

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Dissolution of Hectorite in Inorganic Acids

Komadel

1996

Clays and clay miner.

105

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Abstract--The effect of acid type and concentration on the reaction rate and products of dissolution of hectorite in inorganic acids was investigated. The dissolution of hectorite in hydrochloric (HC1), nitric (HNO3) and sulphuric (H2SO4) acids was characterized using quantitative chemical analysis, infrared (IR) and multinuclear MAS NMR spectroscopies. The rate of dissolution increased with acid concentration and decreased in the order HC1 --> HNO 3 > H2SO 4 at the same molar concentration. No differences were found in the reaction products of hectorite treated with the three acids. The rate of Li dissolution was slightly greater than that of Mg at lesser acid concentrations (0.25 M), indicating that protons preferentially attack Li octahedra. The gradual changes in the Si-O IR bands reflects the extent of hectorite dissolution. The analysis of 298i MAS NMR spectra relative peak intensities with dissolution time and acid concentration provided direct dissolution rates for tetrahedral (Q3) Si. After acid dissolution, most Si was bound in a three dimensional framework site (Q4), but a substantial part also occurred in the Si(OSi)3OH (Q31 OH) and Si(OSi)2(OH)2 (Q22OH) environments. These three sites probably occur in a hydrous amorphous silica phase. Both Aliv and Alw rapidly disappeared from 27A1 MAS NMR spectra of the dissolution products with acid treatment. The changes in IR and MAS NMR spectra of hectorite due to acid dissolution are similar to those of montmorillonite.

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Section: Infrared Spectroscopymentioning

confidence: 75%

Section: Infrared Spectroscopymentioning

confidence: 83%

Section: Infrared Spectroscopymentioning

confidence: 99%

Section: Infrared Spectroscopymentioning

confidence: 99%

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Dissolution of Hectorite in Inorganic Acids

Komadel

1996

Clays and clay miner.

105

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“…(1 is characteristic of the presence of quartz [46]. The absorption in the OH region, centered on about 3300 cm (1 , assigned to amorphous material is considerably weaker than in the finer solids.…”

Section: Infrared Spectramentioning

confidence: 94%

Characterization of sol–gel-derived nano-particles separated from oil sands fine tailings

Majid

Argue

Boyko

et al. 2003

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Methodology has been developed to separate nano-particles of amorphous material from Syncrude fine tailings. Both, separated finer solids and residual coarser solids, were characterized by elemental analysis, X-ray powder diffraction, XPS, SEM, infrared spectroscopy, solid-state NMR, density, and surface area measurements. Based on the results of infrared and X-ray diffraction, the amorphous minerals identified in finer solids included allophanes, halloysite, ferrihydrite, and amorphous silica. The finer fraction also contained some crystalline material consisting of muscovite and traces of quartz. The residual coarser solids consisted mostly of quartz, muscovite, and kaolinite. #

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A novel ATR‐FTIR technique for identifying colloid composition in natural waters

McGuire

Herman

2014

Hydrological Processes

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Although understanding colloid composition has been frequently cited as essential to predicting contaminant transport in natural waters, most current methods to collect and identify colloid composition chemically alter the colloids prior to analysis and fail to identify colloid mineralogy and organic components. This paper presents a new, low‐cost method employing attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR) to identify colloids including organic material in concentrated suspensions. The concentration method employing tangential ultrafiltration at a steady temperature prevents redistribution of dissolved phase and suspended sediments into the colloidal fraction through post‐sampling reactions. ATR‐FTIR allows for direct analysis of concentrated suspensions rather than requiring drying that may alter composition in the colloidal phase, for example, by precipitating carbonates in samples from karst waters. The ability of this technique to monitor variation in colloidal composition is demonstrated through the examination of colloids under two different flow conditions in a karst aquifer and the West Branch of the Susquehanna River in Central Pennsylvania. Copyright © 2014 John Wiley & Sons, Ltd.

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Silica, the Three-dimensional Silicates, Borosilicates and Beryllium Silicates

Cited by 126 publications

References 28 publications

Dissolution of Hectorite in Inorganic Acids

Dissolution of Hectorite in Inorganic Acids

Characterization of sol–gel-derived nano-particles separated from oil sands fine tailings

A novel ATR‐FTIR technique for identifying colloid composition in natural waters

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