Synthesis and Swelling Properties of Saponites with Increasing Layer Charge

Suquet, H.; Iiyama, Jean Toshimichi; Kodama, Hiroshi; Pézerat, H.

doi:10.1346/ccmn.1977.0250310

Cited by 79 publications

(49 citation statements)

References 15 publications

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“…Later, Decarreau (1985) also suggested the use of NaA104 as an A1 source. The saponite obtained had a considerable adsorption capacity and could be effectively used in the disposal of radioactive liquid waste containing Cs or Sr. Suquet et al (1977) synthesized saponites using a method similar to that of Hamilton and Henderson (1968). Booij (1992) had considerable difficulties with this method, due to the formation of forsterite (Mg2SiO4) during the calcination used to remove the nitrates from the gel.…”

Section: H E C T O R I T Ementioning

confidence: 99%

Synthesis of Smectite Clay Minerals: A Critical Review

Kloprogge

Komarneni

Amonette

1999

Clays and clay miner.

318

153

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Abstract--Smectites are one of the most important groups of phyllositicates found in soils and sediments, and certainly one of the most difficult to study. New information about the formation mechanisms, impact of structural features on surface properties, and long-term stability of smectites can best be gained from the systematic study of single-phase specimens. In most instances, these specimens can only be obtained through synthesis under controlled conditions. Syntheses of smectites have been attempted (1) at ambient pressure and low-temperature (< 100~(2) under moderate hydrothermal conditions (100-1000~ pressures to several kbars), (3) under extreme hydrothermal conditions (>1000~ or pressures >10 kbars), and (4) in the presence of fluoride. Of these approaches, syntheses performed under moderate hydrothermal conditions are the most numerous and the most successful in terms of smectite yield and phasepurity. Using hydrothermal techniques, high phase-purity can be obtained for beidellites and several transition-metal smectites. However, synthesis of montmorillonite in high purity remains difficult. Starting materials for hydrothermal syntheses include gels, glasses, and other aluminosilicate minerals. The presence of Mg 2+ seems to be essential for the formation of smectites, even for phases such as montmorillonite which contain low amounts of Mg. Highly crystalline smectites can be obtained when extreme temperatures or pressures are used, but other crystalline impurities are always present. Although the correlation between synthesis stability fields and thermodynamic stability fields is good in many instances, metastable phases are often formed. Few studies, however, include the additional experiments (approach from underand over-saturation, reversal experiments) needed to ascertain the conditions for formation of thermodynamically stable phases. Thorough characterization of synthetic products by modern instrumental and molecular-scale techniques is also needed to better understand the processes leading to smectite formation.

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Section: H E C T O R I T Ementioning

confidence: 99%

Synthesis of Smectite Clay Minerals: A Critical Review

Kloprogge

Komarneni

Amonette

1999

Clays and clay miner.

318

153

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“…molecules is known to occur in high-charge 2 : 1 swelling clays (Harward & Brindley, 1965;Suquet et al, 1977;Suquet, 1978;Egashira et al, 1982;Malla & Douglas, 1987). On the other hand, the 10-5 A reflection appearing with the Mg2+-EG clay ( Fig.…”

Section: Chemical Analysismentioning

confidence: 99%

Surface properties and clay mineralogy of hydrated halloysitic soil clays. II: Evidence for the presence of halloysite/smectite (H/Sm) mixed-layer clays

Delvaux¹,

Herbillon

Vielvoye

et al. 1990

Clay miner.

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A B S TRACT:Six clays from volcanic ash soils at different stages of weathering differ in their relative halloysite content with respect to kaolinite and several surface properties, namely CEC, and exchange selectivity for K +. These three parameters are related to each other in that they all decrease with increasing soil weathering stage. XRD data show that the hydrated 1 : 1 layer-silicates in these clays combine with smectite to form interstratified H/Sm clay minerals. In these mixed-layers, the content and layer charge of smectitic units decrease as the relative halloysite content in the clay decreases. These clays thus depict a weathering sequence that is parallel to the weathering sequence of the soils from which they originate. It is also shown that the smectites in the H/Sm minerals have the distinctive composition and ESR spectrum of Fe-rich 2:1 clay minerals belonging to the beidellite-nontronite series. The information obtained explains why these clays have high CEC and distinct affinities for K + . It is hoped that this study will help to clarify the controversy concerning the CEC and related surface properties attributed to hydrated halloysite.

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“…ethylene glycol complex. From the minerals whose chemical formulae have been reported in the literature (Table 2), it appears that total charge density, rather than tetrahedral charge, influences the complex thickness: high charge smectites have thinner ethylene glycol complexes, analogous to saponites (Suquet et al, 1977). Only a rough correlation can be established using these data, because neither the interlayer cation nor the humidity were controlled during X-ray analysis.…”

Section: Control Over the Thickness Of The Ethylene Glycol Complexmentioning

confidence: 99%

“…Thus, it is anticipated that the thickness of the ethylene glycol complex of most natural (predominantly Na and Ca) dioctahedral smectites and illite/ smectites, analyzed under room conditions, should fall within the 16.6-A to 17.2-A analytical range. The trioctahedral analogues (saponites) give a much larger range of thickness of two-layer ethylene glycol complexes (Suquet et al, 1977), but these minerals do not tend to form mixed layers with illite (Eberl et al, 1977).…”

Section: Control Over the Thickness Of The Ethylene Glycol Complexmentioning

confidence: 99%

Precise Identification of Illite/Smectite Interstratifications by X-Ray Powder Diffraction

Środoń

1980

Clays and clay miner.

250

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Abstract--The thickness of the two-layer ethylene glycol complex of dioctahedral smectites varies under room conditions between 17.3 and 16.5 ]k because of such factors as layer charge density, type of interlayer cation, and relative humidity. Neglecting this variability can give up to 30% error in the X-ray powder diffraction estimation of the smectite:illite ratio of the mixed-layer structures. Three methods have been developed for the interpretation of X-ray powder diffraction patterns of glycolated mixed-layer illite/smectite which take layer-spacing variability into account. The methods include a technique for quantifying the degree of layer ordering. In addition, the proposed techniques minimize the error due to the influence of domain size on positions of reflections. The experimental error can be kept below 5% or below 1% smectite layers, depending on the method applied, provided that the peak positions are measured with the accuracy of ---0.02~

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Synthesis and Swelling Properties of Saponites with Increasing Layer Charge

Cited by 79 publications

References 15 publications

Synthesis of Smectite Clay Minerals: A Critical Review

Synthesis of Smectite Clay Minerals: A Critical Review

Surface properties and clay mineralogy of hydrated halloysitic soil clays. II: Evidence for the presence of halloysite/smectite (H/Sm) mixed-layer clays

Precise Identification of Illite/Smectite Interstratifications by X-Ray Powder Diffraction

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