Understanding the performance of a pilot vermiculite exfoliation system through process mineralogy

Udoudo, Ofonime; Folorunso, Olaosebikan; Dodds, Chris; Kingman, S.W.; Ure, Alex

doi:10.1016/j.mineng.2015.03.023

Cited by 21 publications

(9 citation statements)

References 29 publications

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“…The raw material exhibits three intense reflections at 6.13°, 7.00° and 7.43° and a weak peak at 8.73°, corresponding to the interplanar distances of 1.44, 1.26, 1.19 and 1.01 nm, respectively. They had previously been assigned to different water-layer hydration states (WLHS): 2-WLHS for 1.44 nm, 2/1-WLHS for 1.26 nm, 1-WLHS for 1.19 nm and 1/0-WLHS for 1.01 nm (Suzuki et al , 1987; Udoudo et al , 2015). Therefore, the crude sample may be interpreted as showing the coexistence of highly hydrated states, while the 1000°C sample is dominated by the less hydrated 1/0-WLHS.…”

Section: Resultsmentioning

confidence: 99%

Thermally expanded vermiculite as a risk-free and general-purpose sorbent for hazardous chemical spillages

2019

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Expanded vermiculite with excellent thermal and chemical stability was investigated as a reliable sorbent for hazardous liquid spillages, including those leading to fire and explosion risks. Many expanded samples were prepared by rapid heating using both different temperatures and dissimilar vermiculite dimensions. Their capabilities for hazard clean-up were correlated with the structural characteristics of expanded vermiculite with slit-shaped porosity. When using optimized vermiculite, the moderate sorption capacities of 1.5–3.0 g g−1 were obtained for various hazardous chemicals, including hydrophilic/hydrophobic organic chemicals and strongly acidic/basic solutions. The sorption capacities depended more strongly on physical properties, such as the pore volume of the sorbent and the density of the absorbed liquid, rather than the vermiculite's chemical composition. The void space interconnected by interparticle/intraparticle pores worked as imbibing pathways due to their capillarity, resulting in the rapid, spontaneous sorption of hazardous chemicals. The hazardous chemicals may be removed from a testing vessel via sorption with an efficiency of >94 wt.% for 10 min. These results demonstrate that the expanded vermiculite may be a potential candidate as a reliable general-purpose sorbent for hazardous materials clean-up under harsh conditions.

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Section: Resultsmentioning

confidence: 99%

Thermally expanded vermiculite as a risk-free and general-purpose sorbent for hazardous chemical spillages

2019

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“…Due to the presence of relatively weak non-covalent inter-layer interactions vermiculite can be expanded and ultimately exfoliated into one-to few-layer thick sheets. 32,33 Noteworthy, the degree of exfoliation depends on the composition of the starting material, particle size, nature of interlayer cations, water content, as well as the type of solvent and temperature employed during the exfoliation. The most well-known method of expanding vermiculite crystals relies on rapid heating of the mineral at high temperature (≈1000°C) during short period of time (few minutes).…”

Section: Introductionmentioning

confidence: 99%

Thermal insulation with 2D materials: liquid phase exfoliated vermiculite functional nanosheets

et al. 2018

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“…The XRD patterns corresponding to each condition are shown in Figure 2. The XRD pattern for the nowater condition ((1) in Figure 2) shows that Verm-Cs had hydrobiotite and vermiculite structures [19]. In previous studies, vermiculitized biotite fully loaded with Cs showed two kinds of layers, that is, a Cs layer (10.7 Å, 2θ = 1.08°, dehydrated Cs + is adsorbed in the layer) and a K layer (K layer, 10.1 Å, 2θ = 1.15°) [4,10].…”

Section: Structure Of Verm-cs Under Subcritical Water Conditionsmentioning

confidence: 99%

Mechanistic study on the removal of Cs from contaminated soil by rapid ion exchange in subcritical water

Fukuda

Takahashi

Hara

et al. 2020

Journal of Nuclear Science and Technology

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As a result of the Fukushima nuclear power plant accident in March 2011, massive amounts of soil were contaminated with radioactive Cs. To remediate the contaminated soil, we are developing a desorption technique for removing Cs from soil using subcritical water. In the contaminated soil, the radioactive Cs is stably trapped in the interlayers of the clay minerals, making the use of traditional desorption approaches ineffective. However, we found that rapid ion exchange of Cs with multivalent cations in subcritical water is an effective desorption technique. To understand the mechanism and structural aspects of this process, in situ observations of the soil layer in subcritical water were carried out by high-energy X-ray diffraction together with pair distribution function analysis, and extended X-ray absorption fine structure analysis at SPring-8. Simulated contaminated soil (vermiculite) loaded with non-radioactive Cs + was packed into a column equipped with observation ports and MgCl 2 solution was passed through the column at a fixed flow rate under various conditions. Both the desorption experiments and structural studies indicated that conformational changes of the layer containing Cs + under subcritical water conditions promoted intercalation of the hydrated Mg and trapped Cs + , which facilitated a rapid ion-exchange reaction of Mg 2+ and Cs + .

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Understanding the performance of a pilot vermiculite exfoliation system through process mineralogy

Cited by 21 publications

References 29 publications

Thermally expanded vermiculite as a risk-free and general-purpose sorbent for hazardous chemical spillages

Thermally expanded vermiculite as a risk-free and general-purpose sorbent for hazardous chemical spillages

Thermal insulation with 2D materials: liquid phase exfoliated vermiculite functional nanosheets

Mechanistic study on the removal of Cs from contaminated soil by rapid ion exchange in subcritical water

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