Microstructural investigation of calcium montmorillonite

Matusewicz, Michał; Pirkkalainen, Kari; Liljeström, Ville; Suuronen, Jussi‐Petteri; Root, Andrew; Muurinen, Arto; Serimaa, Ritva; Olin, Markus

doi:10.1180/claymin.2013.048.2.08

Cited by 25 publications

(22 citation statements)

References 20 publications

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“…These materials thus also exhibit shrinkage heterogeneity in addition to swelling heterogeneity already observed by other authors (Ferrage et al, 2005;Devineau et al, 2006). The disappearance of the secondorder diffraction peak (002) at lower humidities can be attributed to interstratification, or the coexistence of different hydration states within the same stack, as previously observed for high dry density Camontmorillonite (Matusewicz et al, 2013). It should be noted that even though there was significant heterogeneity within the samples in terms of tactoid orientation and microscale porosity, the radially averaged SAXD curves only showed minor differences at different measurement points in the same sample.…”

Section: Qualitative Properties Of the Saxd Curvessupporting

confidence: 76%

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X-ray studies on the nano- and microscale anisotropy in compacted clays: Comparison of bentonite and purified calcium montmorillonite

Suuronen

Matusewicz

Olin

et al. 2014

Applied Clay Science

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Exceptional water retention properties make compacted clays and clayrocks attractive materials in waste management applications, e.g. as buffer materials and barrier formations for radionuclide release in geological disposal of spent nuclear fuel elements. Consisting of particles with a very high aspect ratio, clay materials exhibit significant structural anisotropy with potential implications on their performance. In this work, the micron-scale and nanometer-scale anisotropy in compacted calcium montmorillonite and MX-80 bentonite were investigated and quantified under varying humidity conditions; the utilized novel experimental method combines X-ray microtomography (XMT) and small-angle X-ray diffraction to near-simultaneously characterize both the micronscale 3D morphology and mineralogical properties such as clay platelet spacing in platelet stacks (tactoids) and tactoid orientation. Sedimentation during the purification process and lack of accessory minerals were found to induce much stronger orientation in purified Ca-montmorillonite as compared to the MX-80. In highly anisotropic samples, the orientation of microcracks visualized with XMT under low humidity conditions was found to correlate with the local orientation of clay tactoids measured with X-ray diffraction. The proposed experimental method can be applied to a wide range of similar materials, such as shales or samples from clayrock formations.

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Section: Qualitative Properties Of the Saxd Curvessupporting

confidence: 76%

“…An advantage over previous X-ray or neutron diffraction studies (e.g. Bihannic et al, 2001;Devineau et al, 2006;Holmboe et al, 2012;Matusewicz et al, 2013) is that the path of the diffracting X-ray beam within the volume imaged by XMT is known to within approximately 200 μm.…”

Section: Introductionmentioning

confidence: 99%

X-ray studies on the nano- and microscale anisotropy in compacted clays: Comparison of bentonite and purified calcium montmorillonite

Suuronen

Matusewicz

Olin

et al. 2014

Applied Clay Science

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“…Water-saturated structure and porosity of Ca-montmorillonite were studied using X-ray diffraction, small angle X-ray scattering, nuclear magnetic resonance, transmission electron microscopy, and ion exclusion. The obtained results indicate multiple porosity for the bentonite structure [45].…”

Section: Geological Repository For Spent Nuclear Fuelmentioning

confidence: 69%

Montmorillonite: An Introduction to Properties and Utilization

Uddin¹

2018

Current Topics in the Utilization of Clay in Industrial and Medical Applications

117

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Clay mineral is an important material available in nature. With an increasing understanding of clay structure, montmorillonite is realized viable for an enhanced performance in a variety of materials and products in the areas of catalysis, food additive, antibacterial function, polymer, sorbent, etc. Significant development in the use and application of montmorillonite is seen in recent time. This chapter provides an overview of montmorillonite, structure, and properties and particularly discusses its recent utilization in important materials. Montmorillonite is introduced in terms of its natural sources, chemical structure, physical and chemical properties, and functional utilization. The important physical and chemical properties are summarized as particle and layered structure, molecular structure and cation exchange effect, barrier property, and water sorption. This is followed by the important functional utilizations of montmorillonite based on the effects of its chemical structure. The important functional utilization of montmorillonite includes food additive for health and stamina, for antibacterial activity against tooth and gum decay, as sorbent for nonionic, anionic, and cationic dyes, and the use as catalyst in organic synthesis. The environment concerns, to date, do not indicate the adversity for particles used as additive. Studies will be useful which are clearly based on any montmorillonite structure to describe environmental effects.A common characteristic of clay mineral is a fine-grained natural structure in a sheet-like geometry. The sheet-structured hydrous silicates are generally called phyllosilicates [3]. The natural clay particle is smaller than 0.004 mm in diameter that may range from 0.002 to 0.001 mm for quartz, mica, feldspar, iron, and aluminum oxides [4]. Colloidal clay particles are finer and found in layered silicates (<0.001 mm in diameter).Clay minerals may be grouped in four types, shown in Table 1. The group members vary mainly in the layered structure. These include the kaolinite group, the smectite group (montmorillonite group), the illite group, and the chlorite group [5].The kaolinite group has three members including kaolinite, dickite, and nacrite; the formula for kaolinite group is Al 2 Si 2 O 5 (OH) 4 .The illite group is represented by mineral illite, the only common clay type. The general formula for illite is (K, H)Al 2 (Si, Al) 4 O 10 (OH) 2 ⋅ XH 2 O. It is an important rock-forming mineral and main component of shales. The structure of this group is similar to the montmorillonite group with silicate layers sandwiching an aluminum oxide/hydroxide layer in the same stacking sequence.The chlorite group is relatively large. This group is not necessarily considered as part of clays; therefore, it is placed as a separate group in phyllosilicate. The members in chlorite group are mesite, chamosite, cookeite, and daphnite with varying formulas and structures. There is no general formula.The variety of clay minerals is based on the arrangement of tetrahedral and octahedral s...

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“…Transmission Electron Microscopy (TEM) is a high-resolution imaging technique that allows observation of the montmorillonite lamellae structure in compacted unsaturated and saturated bentonites over a wide range of magnifications (Matusewicz et al 2013). TEM provides an observation of various microstructural features, such as nm-sized pores and the arrangement of dense tactoids of montmorillonite layers.…”

Section: Direct Methodsmentioning

confidence: 99%

“…Initially, results obtained through NMR measurements were analysed (Muurinen et al 2013;Matusewicz et al 2013;Ohkubo et al 2016). The intrinsic, state and fabric parameters of bentonites tested through this method are reported in Table 7 and Table 8, respectively.…”

Section: R a F Tmentioning

confidence: 99%

Second ISSMGE R. Kerry Rowe Lecture: On the intrinsic, state, and fabric parameters of active clays for contaminant control

Manassero

2020

Can. Geotech. J.

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The osmotic, hydraulic and self-healing efficiency of bentonite-based barriers for the containment of subsoil pollutants is governed not only by the intrinsic chemicophysical parameters of the bentonite, i.e., the solid phase density, ρsk; the total specific surface, S; the surface density of the electric charge, σ; and the Stern layer thickness, dStern, and fraction, fStern, but also by the chemicomechanical fabric parameters that quantify the structure or texture of the solid skeleton, such as the micro, em, and nano, en, void ratios; the average number of platelets or lamellae per tactoid, Nl,AV; and the solid skeleton effective electric charge concentration, [Formula: see text]. In turn, the fabric parameters are controlled by state parameters, such as the total void ratio, e; and the salt concentration of the equilibrium solution, cs. A theoretical framework has been developed to describe the relationships between the aforementioned intrinsic, state, and fabric parameters for a bentonite barrier and its performance parameters: the hydraulic conductivity, k; the effective diffusion coefficient, [Formula: see text]; the chemico-osmotic efficiency coefficient, ω; and the osmotic swelling pressure, usw. The proposed theoretical hydrochemicomechanical model has been validated through comparison with a large amount of experimental results.

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Microstructural investigation of calcium montmorillonite

Cited by 25 publications

References 20 publications

X-ray studies on the nano- and microscale anisotropy in compacted clays: Comparison of bentonite and purified calcium montmorillonite

X-ray studies on the nano- and microscale anisotropy in compacted clays: Comparison of bentonite and purified calcium montmorillonite

Montmorillonite: An Introduction to Properties and Utilization

Second ISSMGE R. Kerry Rowe Lecture: On the intrinsic, state, and fabric parameters of active clays for contaminant control

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