Bentonite Powder XRD Quantitative Analysis Using Rietveld Refinement: Revisiting and Updating Bulk Semiquantitative Mineralogical Compositions

Cuevas, Jaime; Cabrera, Miguel Ángel Torregrosa; Fernández, Carlos Y.; Mota-Heredia, Carlos; Fernández, Raúl; Torres, Elena; Turrero, M. J.; Ruiz, A.

doi:10.3390/min12060772

Cited by 11 publications

(4 citation statements)

References 39 publications

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“…In this study, FEBEX bentonite from Cortijo de Archidona, Serrata de Níjar, Almería, Spain [54,55], considered the standard buffer material for radioactive waste storage in Spain [56], was pre-treated to produce Mg-bentonite. Natural bentonite contains 85 ± 10 wt.% montmorillonite [57], and accessory minerals, such as quartz, cristobalite, calcite and feldspars. It also contains traces of Fe minerals such as magnetite and goethite.…”

Section: Methodsmentioning

confidence: 99%

Geochemical Evolution of Mg-Bentonite Affected by the Contact of Carbon Steel and a Hydrothermal Gradient

Mota-Heredia,

Cuevas,

Fernández

2024

Applied Sciences

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Carbon steel and bentonite are materials selected as engineered barriers for high-level radioactive waste confinement. Their long-term interaction must be evaluated to confirm the barrier’s stability. Three laboratory experiments of the carbon steel—Mg-bentonite interaction were conducted for 1, 6, and 22 months under a hydrothermal gradient. Changes in bentonite’s water content, specific surface area, and cation exchange capacity were measured. Mineralogy was studied by X-ray diffraction and scanning electron microscopy. The redistribution of aqueous species and the redox state of iron were determined across the bentonite columns. Results indicated water saturation after 22 months. The specific surface area of bentonite was reduced near contact with the steel, while the cation exchange capacity mostly decreased at 3–6 mm from the steel interface. The corrosion rate decreased with time and bentonite enriched in Fe in the first 1.5 mm from the steel contact. The formation of new Fe-bearing minerals, such as di-tri ferri-sudoite, magnetite, hematite, maghemite, lepidocrocite, siderite and ankerite was observed. Aqueous species redistributed in the porewater of bentonite with decreasing concentrations of Fe and Cl as a function of time and increasing concentrations of Na, Ca and SO4 after 22 months. This occurs under conditions where the bentonite is saturated with Mg, which conditioned the formation and nature of iron clay minerals with time.

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Section: Methodsmentioning

confidence: 99%

Geochemical Evolution of Mg-Bentonite Affected by the Contact of Carbon Steel and a Hydrothermal Gradient

Mota-Heredia,

Cuevas,

Fernández

2024

Applied Sciences

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“…It is considered as a total approach to mineralogical quantification. In addition, χ 2 < 5 was considered as acceptable refinement statistics based on the complexity of soil samples examined in this study and based on previous similar work of clay material XRD analysis (36).…”

Section: Xrd Quantificationmentioning

confidence: 99%

Rapid detection of soil carbonates by means of NIR spectroscopy, deep learning methods and phase quantification by powder X-ray diffraction

Chiniadis,

Tamvakis

2024

Journal of the Association of Greek Chemists

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In this study we propose a novel rapid and efficient way to predict carbonates content in soil by means of Fourier Transform Near-Infrared (FT-NIR) reflectance spectroscopy and by use of deep learning methods. In addition to using traditional machine learning algorithms, we exploited multiple deep learning methods, such as: 1) a Multi-Layered Perceptron Regressor (MLP) and 2) a Convolutional Neural Network (CNN) in an attempt to compare their performance with other classical machine learning algorithms, which up until now were considered the field’s standards, such as Partial Least Squares Regression (PLSR), Cubist and SupportVectorMachines (SVM) on the combined dataset of two NIR spectral libraries: Kellogg Soil Survey Laboratory (KSSL) of the United States Department of Agriculture (USDA), a dataset of soil samples reflectance spectra collected nationwide, and Land Use and Coverage Area Frame Survey (LUCAS) TopSoil-2015 (European Soil Library) which contains soil sample absorbance spectra from all over the European Union, and use them to predict carbonate content on never-before-seen soil samples. In this study, absorbances in the NIR spectral region (1150-2500 nm) were utilized in two different ways: a) as one-dimensional data and b) as two-dimensional spectrograms which, to our knowledge, is a completely novel approach that has rarely been researched. Quantification of carbonates by means of X-ray-Diffraction is in good agreement with the volumetric method and the MLP prediction. Our work contributes to rapid carbonates content prediction in soil samples in cases where: 1) no volumetric method is available and 2) only NIR spectra absorbance data are available.

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“…An examination of these works revealed that 3 papers (10%) utilized experimental methodology, 6 papers (21%) discussed the reported results and compared them with their findings, and 20 papers (69%) cited 1 or more of Dr. Santos’s papers in the introduction section of their papers to explain a concept (Table S1 in the Supporting Information). More details and discussion about these relevant studies ,,− are available in the Supporting Information file alongside other analyses on citation usage, publication sources, country, institutional collaboration analyses, and paper classification according to scientific disciplines and the United Nations Sustainable Development Goals. A scientometric analysis is a powerful tool for researchers to gauge the impact of their work and to connect with the broader scientific community beyond what other networking activities, such as conferences and webinars, allow.…”

Section: Scientometric Analysismentioning

confidence: 99%

Multiscale Process Intensification of Waste Valorization Reactions

Santos,

Zhang,

Bakhshoodeh

2023

Acc. Chem. Res.

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Conspectus The central theme of this Account is the development of intensified and sustainable chemical processes for the sequestration of CO2 in synergism with the utilization of wastes of industrial, urban, and agricultural origins. A challenge when working with solid waste–fluid reactions is that mass transfer limitations across solid–liquid, solid–gas, and gas–liquid interfaces and unfavorable thermodynamics lead to slow reaction rates, incomplete reaction conversions, high energy expenditure and processing costs, and inadequate product properties. The traditional macroscale approaches to overcoming slurry reaction limitations can be effective; however, they come at a cost to the environment. In the treatment or valorization of low-grade and waste resources, such conventional approaches are often unfeasible on an industrial scale. Sustainable solutions are thus needed. In the last six years, we have been exploring and developing approaches to overcoming reaction rate limitations of slurry reactions of environmental relevance by concurrently applying process intensification strategies and multiscale engineering approaches. The scientific approach has relied on laboratory-scale experiments to test and refine the devised multiscale process intensification strategies, with thermodynamic and computational modeling work supporting the experimental work and with advanced characterization techniques being used to elucidate reaction and transport mechanisms and aid the development of nanoscale reaction models and micro- and macroscale process models. The research streams, associated with the four key references, discussed next are (a) brine carbonation; (b) mineral carbonation and enhanced weathering; (c) process intensification and integration; and (d) characterization techniques. Within the four research streams, a number of mineral carbonation processes have been investigated and can be classified as (i) ambient weathering and carbonation; (ii) gas-(wet) solid accelerated carbonation; (iii) aqueous accelerated carbonation; (iv) supercritical accelerated carbonation; and (v) CO2 mineralization from brine. In some cases, the research was aimed at producing valuable products with reduced environmental risk or a reduced carbon footprint, such as an organomineral fertilizer and zeolites. In other cases, the aim was to assess the reactivity of minerals to match the right feedstock with the right carbonation process, in view of maximizing net carbon sequestration. There were also cases where the carbonation process was reimagined by the use of innovative reaction conditions, reactors, and reagents. The experience with accelerated weathering and carbonation in engineered processes has been translated into the field of enhanced rock weathering (ERW) in agriculture, where the multidisciplinary approach used has served to advance ERW science and technology in ways that have had a resounding effect on recent commercial deployment. The completed research serves to encourage the adoption of process intensification technologies ...

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Bentonite Powder XRD Quantitative Analysis Using Rietveld Refinement: Revisiting and Updating Bulk Semiquantitative Mineralogical Compositions

Cited by 11 publications

References 39 publications

Geochemical Evolution of Mg-Bentonite Affected by the Contact of Carbon Steel and a Hydrothermal Gradient

Geochemical Evolution of Mg-Bentonite Affected by the Contact of Carbon Steel and a Hydrothermal Gradient

Rapid detection of soil carbonates by means of NIR spectroscopy, deep learning methods and phase quantification by powder X-ray diffraction

Multiscale Process Intensification of Waste Valorization Reactions

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