Occurrence characteristics of free iron oxides in soil microstructure: evidence from XRD, SEM and EDS

Zhang, Xianwei; Kong, Lingwei; Cui, Xiao-Lei; Yin, Song

doi:10.1007/s10064-015-0781-2

Cited by 83 publications

(22 citation statements)

References 35 publications

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“…This can be put down to being a consequence of the changes in both soil constituent and structure. On the one hand, the addition of 10% nZVI is at a high percentage load with the forceful capacity of oxidation reaction to change the soil constituent (Gil-Diaz et al, 2014); the increased water holding capacity can be partially attributed to the generation of iron oxide-hydroxides such as ferrihydrite (Fe5HO8•4H2O), schwertmannite (Fe8O8(OH)6(SO)•nH2O), and goethite (α-FeOOH) (Velimirovic et al, 2018;Zhang et al, 2016). On the other, an increase in microbubbles enabled itself to readily adsorb moisture and humidity (Lawrence and Jiang, 2017).…”

Section: Undrained Shear Strengthmentioning

confidence: 99%

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

Zhou

Liu

et al. 2019

Science of The Total Environment

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This study demonstrates the feasibility of nanoscale Zero-Valent Iron (nZVI) for simultaneous stabilization of Pb and improvement of soil strength via batch experiments. The soil samples were prepared using slurry and pre-consolidation method at nZVI doses of 0.2%, 1%, 5%, and 10% (by dry weight). The physicochemical and geotechnical properties of Pb-contaminated soil treated by nZVI were analyzed. The results indicate that the contamination of Pb(II) resulted in a notable reduction in the undrained shear strength of soil from 16.85 kPa to 7.25 kPa. As expected, the Pb in exchangeable and carbonate-bound fractions decreased significantly with the increasing doses of nZVI. Meanwhile, the undrained shear strength of Pb-contaminated soil enhanced substantially as the increase of nZVI, from 25.83 kPa (0.2% nZVI treatment) to 69.33 kPa (10% nZVI treatment). An abundance of bubbles, generated from the oxidation of nZVI, was recorded. The mechanisms for simultaneous stabilization of Pb and soil improvement primarily include: 1) the precipitation and transformation of Pb-/Fe-hydrated oxides on the soil particles and their induced bounding effects; 2) the increased drainage capability of soil as the occupation of nZVI aggregates and bubbles in the macropores space and 3) the lower soil density derived from the increase in microbubbles retained in the soil. This study is provided to facilitate the application of nZVI in the redevelopment of contaminated soil.

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Section: Undrained Shear Strengthmentioning

confidence: 99%

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

Zhou

Liu

et al. 2019

Science of The Total Environment

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“…Ç elik et al [18] studied photomicrographs and textures of the Ayazini tuffs using SEM. Zhang et al [19] used XRD, SEM, and energy dispersive spectrometry to study alteration of physical and chemical properties, mineral composition, and microstructures caused by the removal of free iron oxides.…”

Section: Shock and Vibrationmentioning

confidence: 99%

Experimental Study on the Softening Characteristics of Sandstone and Mudstone in Relation to Moisture Content

Sun

et al. 2017

Shock and Vibration

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The kinetics of fluid-solid coupling during immersion is an important topic of investigation in rock engineering. Two rock types, sandstone and mudstone, are selected in this work to study the correlation between the softening characteristics of the rocks and moisture content. This is achieved through detailed studies using scanning electron microscopy, shear tests, and evaluation of rock index properties during exposure to different moisture contents. An underground roadway excavation is simulated by dynamic finite element modeling to analyze the effect of moisture content on the stability of the roadway. The results show that moisture content has a significant effect on shear properties reduction of both sandstone and mudstone, which must thus be considered in mining or excavation processes. Specifically, it is found that the number, area, and diameter of micropores, as well as surface porosity, increase with increasing moisture content. Additionally, stress concentration is negatively correlated with moisture content, while the influenced area and vertical displacement are positively correlated with moisture content. These findings may provide useful input for the design of underground roadways.

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“…This phenomenon was determined to be due to the relatively distinct decrease in the proportions of quartz and feldspar, while the proportion of clay minerals increased in every specimen since the clay particles were collected. Furthermore, in the case of iron oxides, an identifiable XRD pattern was recorded due to the concentration effect [60] that covered the upper part of the flaky plate, which was predominantly exposed because of the characteristics of the clay mineral particles arranged along the b-axis in the oriented specimens, as shown in Figure 6. However, in the case of the diffraction patterns of the bulk powder, the peaks of mica are difficult to analyze, as they are present in small amounts due to the higher diffraction intensity of quartz and feldspar.…”

Section: Clay Particle Xrd and Firing Parametersmentioning

confidence: 99%

X-ray Diffraction Analysis of Clay Particles in Ancient Baekje Black Pottery: Indicator of the Firing Parameters

et al. 2021

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An X-ray diffraction (XRD) analysis was conducted after separating clay particles from three shards, to analyze the production technique of black pottery excavated from a historical site of ancient Baekje in Seoul, South Korea. Through the analysis, clay minerals and iron oxides that were not recognized in the XRD patterns of the bulk powder samples were identified. A pottery type with a blackened portion from the surface to the margin and the core was estimated to have been produced in a reduction firing environment of less than 900 °C, by detecting illite and magnetite. As for the other blackened pottery, a brown soil color remained in the core, and the presence of illite and kaolin was confirmed. In addition, while magnetite was detected on the black surface and margin, hematite was detected in the core. These results confirm that this type of blackened pottery was produced through reduction firing at a temperature below 550 °C. In particular, the results indicate that there is a new category of pottery, produced by firing at lower temperatures in a reduction atmosphere, previously not reported by research on ancient Baekje black pottery, which could be discovered due to its specific clay particles.

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Occurrence characteristics of free iron oxides in soil microstructure: evidence from XRD, SEM and EDS

Cited by 83 publications

References 35 publications

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

Experimental Study on the Softening Characteristics of Sandstone and Mudstone in Relation to Moisture Content

X-ray Diffraction Analysis of Clay Particles in Ancient Baekje Black Pottery: Indicator of the Firing Parameters

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