Montmorillonite chemical analysis

Malucelli, F. Terribile, F. Colombo, C. (1999) Mineralogy, micromorphology and chemical analysis of andosols on the Island of Sao Miguel (Azores). Geoderma88 73-98 Mamedov, A. Ostrander, J. Aliev, F. Kotov, N.A. (2000) Stratified assemblies of magnetite nanoparticles and montmorillonite prepared by layer-by-layer assembly. Langmuir 16 3941-3949... 

Kaolinite seldom occurs interstratified with 2 1 clay minerals although Sudo and Hayashi (1956) described a randomly interstratified kaolinite-montmorillonite in acid clay deposits in Japan. On the basis of the chemical analysis (Si02 = 41.94, A1203 = 30.12, Fe203 = 2.42, FeO = 0 21, MgO = 1.52, CaO = 0.32, Ti02 = 0.40, H20+ =... 

Bentonite is a native colloidal hydrated aluminum silicate consisting mainly of montmorillonite, Al203-4Si02-H20 it may also contain calcium, magnesium, and iron. The average chemical analysis is expressed as oxides, see Table I, in comparison with magnesium aluminum silicate. 

Assuming that goethite and kaolinite are finite solids, enter the chemical analysis into M1NTEQA2, except for the Fe and A1 concentrations. Compare computed ZFe(lII)(aq) and ZAl(aq) concentrations at saturation with goethite and kaolinite to the values in the table. How much Fe and A1 may be in suspension Next assume that the water is in equilibrium with goethite and montmorillonite (make them finite solids). Now what is the computed ZAl(aq) concentration ... 

Another explanation was the following. The organomontmorillonite used was a natural montmorillonite that contained iron. Chemical analysis of the clay confirmed the presence of a low amount of iron. It was recalled that iron and, in more general terms, metals are likely to induce the photochemical degradation of polymers. Iron at low concentration had a prooxidant effect that was due to the metal ion of iron that can initiate the oxidation of the polymer by the well-known redox reactions with hydroperoxides [93]. It was concluded that the transition metal ions, such as Fe, displayed a strong catalytic effect by redox catalysis of hydroperoxide decomposition, which was probably the most usual mechanism of filler accelerating effect on polymer oxidation. A characteristic of such catalytic effect was that it did not influence the steady-state oxidation rate, but it shortened the induction time. 

Procedures leading to preparation of vanadium-doped alumina- and/or titania-pillared montmorillonites are described and physicochemical characterization (chemical analysis, XRD, BET, ESR) of the products is provided. Results show that introduction of vanadium into the pillared montmorillonites leads to a rigid association of the dopant with pillars, irrespective of the method of preparation. The mode of vanadyl attachment in alumina-pillared samples does not depend on the mode of preparation, while in titania-pillared montmorillonite it does. Certain degree of delocalization of the unpaired electron into ligands and increased in-plane 7t-covalent bonding is observed for vanadyl ions present in the co-pillared (V-Ti)-PILC samples which also show particularly high activity in catalytic ammoxidation of m-xylene to nitrile product, as monitored by IR. A hypothesis is advanced that this effect is due to the unique character of vanadyl species present in these catalysts. 

A. Vazquez, M. Ldpez, G. Kortaberria, L. Martm, and I. Mondragon, Modification of montmorillonite with cationic surfactants Thermal and chemical analysis including CFG determination. Applied Clay Science, 41 (2008), 24—36. 

The reporting of mica in soil clays depends somewhat on the method of detection. Jackson and Mackenzie [1964] state that some soil clays, which show no indication of mica based on X-ray diffraction, may contain from 5 to 20 % or more of micas based on chemical analysis and on the basis of 10% K2O in mica. According to Schuffelen and van der Marel [1955], soils high in allophane fix very considerable quantitities of potassium. Thus, potassium does not necessarily reside altogether in micas and feldspars in soils. Some of it may be in amorphous material. However, some of the potassium may be in micalike zones of particles, which are largely montmorillonite or vermiculite and have weathered from micas. Such zones may be too small to be detected by X-ray diffraction (Knibbe and Thomas [1972]). 

Frank-Kamenetsky et al [1965] have given the name tosudite to a regular interstratification of dioctahedral chlorite and montmorillonite. The material has a basal spacing of 28.5 A in its natural state, increases to 32.0 A on glycerol solvation, and decreases to 23.6 A on heating. The authors describe the chlorite as dioctahedral in both sheets, but could not obtain a pure sample for chemical analysis. The fi (060) value of 1.497 A supports the view of two dioctahedral sheets, but further confirmation is desirable. 

The similar chlorite-montmorillonite interstratification has been identified by Di Paola [1968] from the upper cretaceous in Argentina and by Morelli [1967] in Italy (X-ray, D.T.A., chemical analysis and cation exchange data). 

In each of the different parageneses outlined here, the instability of a mineral can be denoted by its replacement with one or usually several minerals. The rocks in these facies are typified by multi-phase assemblages which can be placed in the K-Na-Al-Si system. This is typical of systems where the major chemical components are inert and where their masses determine the phases formed. The assumptions made in the analysis up to this point have been that all phases are stable under the variation of intensive variables of the system. This means that at constant P-T the minerals are stable over the range of pH s encountered in the various environments. This is probably true for most sedimentary basins, deep-sea deposits and buried sedimentary sequences. The assemblage albite-potassium feldspar-mixed layered-illite montmorillonite and albite-mixed layered illite montmorillonite-kaolinite represent the end of zeolite facies as found in carbonates and sedimentary rocks (Bates and Strahl,... 

It is important to note two things in this analysis first, the reactions which govern silicate phase equilibria occur in a system closed to large-scale chemical migration. This corresponds to a pore-water sediment system of local equilibrium. Second, the most striking mineralogical change—the crystallization of feldspar—is, in fact, the result of the instability of another phase, montmorillonite. The use of... 

The results of the quantitative analysis of montmorillonite samples obtained with different Ca-montmorillonite/lead ion ratio and pH are shown in Table 2.14 for the surfaces with even lead distribution. The chemical composition of lead enrichments is shown in Table 2.15. 

The characterization of the physical and chemical changes that occur in montmorillonite/PDMS nanocomposite elastomers as they are thermally aged is reported. Broadband Dielectric Spectroscopy (BDS) was used to track changes in the physical interaction between the polymer and clay associated with increases in non-oxidative thermal stability (as determined by TGA). The evolution of volatile siloxane species from the elastomers was characterized with Thermal Volatilization Analysis (TVA). Results suggest that the improved thermal stability and the increases in polymer/clay association are a result of significant re-structuring of the polymer network. 

With fresh activated-clay catalyst, endothermic peaks are observed at temperatures of about 300, 1200, and 1600°F. These three peaks are attributed to loss of physically adsorbed water, loss of chemically bound (hydroxyl) water, and collapse of the montmorillonite structure, respectively. The hydroxyl water originally present amounts to 3 or 4%. The magnitude of the peak at 1200°F. decreases if the sample is heated above 800°F. prior to thermal analysis, and disappears completely if the sample is calcined at 1100°F. The thermal-analysis curve for the dehydrated catalyst is flat up to the point at which the montmorillonite structure begins to disappear. If the catalyst has not been heated above 1450°F., it becomes rehydrated upon exposure to moisture and a new endothermic peak appears in the curve between 800 and 1000°F. The size of the new peak increases as that of the original hydroxyl-water peak decreases it corresponds to 1.5 to 2.0% sorbed water with catalyst that has been rehydrated after calcination at 1100°F. The rehydration capacity of the catalyst decreases as the catalyst becomes partially deactivated with use. 

Chemical characterization of fines implies the elemental and mineral compositional analysis of migratory fines in porous media. Khilar and Fogler (1998) presented the range in chemical composition of migratory clays primarily of kaolinite, illite, montmorillonite, and chlorite particles in Table 5.6. We observe from this table that silica, Si02, and alumina are the major minerals. 

The evolved gas of the first step around 300 °C of the montmorillonite complex was identified as n-hexylamine by GC-analysis (Fig. 3), which indicates the simple desintercalation of amines. According to the TG-analysis of the first step, approximately 25% of the total weight decrease was measured, and this indicates that the layer charge originating from the octahedral substitution might be 0.18 per unit cell composition. On the basis of this result, along with that of the layer charge estimation by the n-alkylammonium method, the chemical equation of the first step can be formulated as follows ... 

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