Effects of Sample Size and Packing in the Thermogravimetric Analysis of Calcium Montmorillonite STx-1

Schilling, Michael

doi:10.1346/ccmn.1990.0380513

Cited by 16 publications

(10 citation statements)

References 3 publications

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“…Characterization of the unreacted clay indicated three weight loss steps at ∼60 • C, ∼110 • C, and ∼650 • C representing a loss of adsorbed water, chemically bound water associated with the exchangeable Ca 2+ cation, and structural water. These results are consistent with values reported by Schilling (1990) for STX-1.…”

Section: Experimental Methods and Materialssupporting

confidence: 93%

“…Naturally occurring low iron montmorillonite (STX-1), obtained from the Clay Mineral Repository (Columbia, MO), was used for all of the experiments and has been previously well characterized (Olphen et al, 1979;Bigham, 1986, 1987;Schilling, 1990;Chipera and Bish, 2001;Madejova and Komadel, 2001;Mermut and Cano, 2001;Mermut and Lagaly, 2001). The as received clay which has virtually all the layer charge emanating from the octahedral sites, has the following published structural formula (Ca 0.27 Na 0.04 K 0.01 )(Al 2.41 Fe 3+ 0.09 Mn tr Mg 0.71 Ti 0.03 ) 2 Si 8 O 20 (OH) 4 .…”

Section: Experimental Methods and Materialsmentioning

confidence: 99%

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In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

Schaef

Ilton

Qafoku

et al. 2012

International Journal of Greenhouse Gas Control

134

222

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Section: Experimental Methods and Materialssupporting

confidence: 93%

Section: Experimental Methods and Materialsmentioning

confidence: 99%

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

Schaef

Ilton

Qafoku

et al. 2012

International Journal of Greenhouse Gas Control

134

222

View full text Add to dashboard Cite

“…Naturally occurring low iron MM (STX-1), obtained from the Clay Mineral Repository (Columbia, MO), that is well characterized, − was used as a starting material. The as received clay, which has virtually all the layer charge emanating from the octahedral sites, has the published structural formula (Ca 0.27 Na 0.04 K 0.01 )(Al 2.41 Fe 3+ 0.09 Mn tr Mg 0.71 Ti 0.03 ) 2 Si 8 O 20 (OH) 4 .…”

Section: Methodsmentioning

confidence: 99%

CO₂ Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements

Rother

Ilton

Wallacher

et al. 2012

Environ. Sci. Technol.

126

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Geologic storage of CO(2) requires that the caprock sealing the storage rock is highly impermeable to CO(2). Swelling clays, which are important components of caprocks, may interact with CO(2) leading to volume change and potentially impacting the seal quality. The interactions of supercritical (sc) CO(2) with Na saturated montmorillonite clay containing a subsingle layer of water in the interlayer region have been studied by sorption and neutron diffraction techniques. The excess sorption isotherms show maxima at bulk CO(2) densities of ≈ 0.15 g/cm(3), followed by an approximately linear decrease of excess sorption to zero and negative values with increasing CO(2) bulk density. Neutron diffraction experiments on the same clay sample measured interlayer spacing and composition. The results show that limited amounts of CO(2) are sorbed into the interlayer region, leading to depression of the interlayer peak intensity and an increase of the d(001) spacing by ca. 0.5 Å. The density of CO(2) in the clay pores is relatively stable over a wide range of CO(2) pressures at a given temperature, indicating the formation of a clay-CO(2) phase. At the excess sorption maximum, increasing CO(2) sorption with decreasing temperature is observed while the high-pressure sorption properties exhibit weak temperature dependence.

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“…This is a mass effect: while 100-150 mg are used in each run of TGA, only 6-8 mg are enough for a DTA run. These differences have been explained by Schilling (1990) and are associated with diffusional effects depending upon the amount and compactness of the sample. This effect does not invalidate the qualitative results of TGA, although the temperatures from the DTA are the most exact.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

Condensation of Olefins on Clays. Gas-Solid Systems. Part I: Gravimetric Methods

Choren

Moronta

Varela

et al. 1997

Clays and clay miner.

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Abstract--The adsorption-condensation of olefins was studied on 7 adsorbents: 2 commercial clays, a natural clay and its protonated form, ~-alumina and porous and nonporous silicas. These adsorbents were characterized by X-ray diffraction (XRD), chemical analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and determination of specific surface area measurement by the BET method. The experiments were carried out gravimetrically, in gas-or vapor-solid systems, at 25 ~ and on adsorbents dried at 120 ~ Adsorption-condensation of olefins are fast processes, diffusion controlled. Alumina and silicas adsorb olefins and paraffins only reversibly, but are unable to condense olefins. The water polarized by the countercations is the source of BrCnsted acid sites. When the gas phase is evacuated or swept with inert gas, the condensation terminates. On clays, paraffins are reversibly adsorbed but no condensation was observed.

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Effects of Sample Size and Packing in the Thermogravimetric Analysis of Calcium Montmorillonite STx-1

Cited by 16 publications

References 3 publications

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

CO₂ Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements

Condensation of Olefins on Clays. Gas-Solid Systems. Part I: Gravimetric Methods

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Effects of Sample Size and Packing in the Thermogravimetric Analysis of Calcium Montmorillonite STx-1

Cited by 16 publications

References 3 publications

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

In situ XRD study of Ca2+ saturated montmorillonite (STX-1) exposed to anhydrous and wet supercritical carbon dioxide

CO2 Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements

Condensation of Olefins on Clays. Gas-Solid Systems. Part I: Gravimetric Methods

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Product

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CO₂ Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements