scholarly journals Effects of Hydraulic Gradient and Clay Type on Permeability of Clay Mineral Materials

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1064
Author(s):  
Masanori Kohno
Keyword(s):  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Clay Mineral ◽  
Specific Surface Area ◽  
Hydraulic Gradient ◽  
Consistency Index ◽  
Hydrogen Energy ◽  
The Difference ◽  
Mineral Type

Considering the relevance of clay mineral-bearing geomaterials in landslide/mass movement hazard assessment, various engineering projects for resource development, and stability evaluation of underground space utilization, it is important to understand the permeability of these clay mineral-based geomaterials. However, only a few quantitative data have been reported to date regarding the effects of the clay mineral type and hydraulic gradient on the permeability of clay mineral materials. This study was conducted to investigate the permeability of clay mineral materials based on the clay mineral type, under different hydraulic gradient conditions, through a constant-pressure permeability test. Comparative tests have revealed that the difference in the types of clay mineral influences the swelling pressure and hydraulic conductivity. In addition, it has been found that the difference in water pressure (hydraulic gradient) affects the hydraulic conductivity of clay mineral materials. The hydraulic conductivity has been found to be closely associated with the specific surface area of the clay mineral material. Furthermore, the hydraulic conductivity value measured is almost consistent with the value calculated theoretically using the Kozeny–Carman equation. Moreover, the hydraulic conductivity is also found to be closely associated with the hydrogen energy, calculated from the consistency index of clay. This result suggests that the hydraulic conductivity of clay mineral materials can be estimated based on the specific surface area and void ratio, or consistency index of clay.

Clays are not created equal – effects of clay mineral type on soil hydraulic and mechanical properties

2021 ◽  
Author(s):  
Peter Lehmann ◽  
Ben Leshchinsky ◽  
Surya Gupta ◽  
Ben Mirus ◽  
Samuel Bickel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Internal Friction ◽  
Specific Surface ◽  
Surface Area ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Specific Surface Area ◽  
Friction Angle ◽  
Tropical Soils ◽  
Mineral Type

<p>Clay minerals dominate the soil colloidal fraction and often carry the largest specific surface area – a property that controls various soil hydraulic and mechanical properties (SHMPs; e.g. water retention, permeability, and internal friction). Differences in microscale structure among clay mineral types in tropical and temperate regions affect the specific surface area and result in higher permeability and internal friction angle values for tropical soils with inactive kaolinite clay minerals. Presently, the soil clay size fraction used to parameterize SHMPs with pedotransfer functions (PTFs) ignores clay mineral type, leading to inconsistent parameter representation. In this study, we present new PTFs informed by clay minerals, enabling enhanced estimation of friction angle and saturated hydraulic conductivity. To capture higher conductivity and lower air entry values in tropical soils, we developed a hierarchical packing model and validated this new PTF approach using literature data from various tropical regions. We leveraged recent global maps of clay minerals to demonstrate that a strong climatic and spatial segregation of active and inactive clays enable spatially resolved consideration of clay mineral type in SHMP estimation. We applied these clay-informed PTFs to improve SHMP representation regionally with implications for a wide range of hydrological and geomechanical Earth surface processes.</p>

scholarly journals The referential grain size and effective porosity in the Kozeny–Carman model

2016 ◽  
Author(s):  
K. Urumović ◽  
K. Urumović Sr.
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Effective Porosity ◽  
Critical Conditions ◽  
Saturated Porous Media ◽  
New Developments ◽  
Mean Grain Size

Abstract. In this paper, the results of permeability and specific surface area analyses as functions of granulometric composition of various sediments (from silty clays to very well-graded gravels) are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters expressing an effect of the forces operating on fluid movement through the saturated porous media. This paper suggests procedures for calculating referential grain size and determining effective (flow) porosity, which result in parameters that reliably determine the specific surface area and permeability. These procedures ensure the successful application of the Kozeny–Carman model up to the limits of validity of Darcy’s law. The value of effective porosity in the referential mean grain size function was calibrated within the range of 1.5 μm to 6.0 mm. The reliability of the parameters applied in the KC model was confirmed by a very high correlation between the predicted and tested hydraulic conductivity values (R2=0.99 for sandy and gravelly materials; R2=0.70 for clayey-silty materials). The group representation of hydraulic conductivity (ranging from 10–12 m/s up to 10–2 m/s) presents a coefficient of correlation of R2=0.97 for a total of 175 samples of various deposits. These results present new developments in the research of the effective porosity, the permeability and the specific surface area distributions of porous materials. This is important because these three parameters are critical conditions for successful groundwater flow modeling and contaminant transport. Additionally, from a practical viewpoint, it is very important to identify these parameters swiftly and very accurately.

Effects of Carbonation on the Specific Surface BET of Cement Mortar Measured by Two Different Methods: Nitrogen Adsorption and Water Adsorption

2014 ◽  
Vol 931-932 ◽  
pp. 421-425 ◽  
Author(s):  
Son Tung Pham ◽  
William Prince
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Adsorption ◽  
Cement Mortar ◽  
Nitrogen Adsorption ◽  
Accelerated Carbonation ◽  
Molecular Sizes ◽  
The Difference ◽  
Adsorption Desorption

The objective of this work was to examine the microstructural changes caused by the carbonation of normal mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO2concentration. The evolutions of the pore size distribution and the specific surface area during carbonation were calculated from the adsorption - desorption isotherms of water vapour and nitrogen. Conflicts observed in the results showed that the porous domains explored by these two methods are not the same due to the difference in molecular sizes of nitrogen and water. These two techniques therefore help to complementarily evaluate the effects of carbonation. The study also helped to explain why results in the literature diverge greatly on the influence of carbonation on specific surface area.

scholarly journals Comparison of the Biological and Chemical Synthesis of Schwertmannite at a Consistent Fe2+ Oxidation Efficiency and the Effect of Extracellular Polymeric Substances of Acidithiobacillus ferrooxidans on Biomineralization

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1739 ◽  
Author(s):  
Yongwei Song ◽  
Yelin Liu ◽  
Heru Wang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acidithiobacillus Ferrooxidans ◽  
Extracellular Polymeric Substances ◽  
Shell Shape ◽  
X Ray ◽  
Removal Capacity ◽  
The Difference ◽  
Oxidation Efficiency

Schwertmannite is an environmental mineral material that can promote the natural passivation of heavy metal elements, thereby reducing environmental pollution from toxic elements. However, the fundamental reason for the difference between the chemically (H2O2-FeSO4) and biologically (Acidithiobacillus ferrooxidans-FeSO4) synthesized schwertmannite is still unclear. In this study, X-ray diffraction, scanning electron microscopy, the Brunauer–Emmett–Teller method, and X-ray fluorescence spectrometry were used to compare the structure, specific surface area, and elemental composition of schwertmannite synthesized by biological and chemical methods. The removal capacity of As(III) by the two kinds of schwertmannite and the effects of extracellular polymeric substances (EPS) on biogenetic schwertmannite were also investigated. At a consistent Fe2+ oxidation efficiency, the chemical method synthesized more schwertmannite than the biological method over a 60-h period. The biosynthesized schwertmannite had a “chestnut shell” shape, with a larger particle size and specific surface than the chemically synthesized schwertmannite, which was relatively smooth. The saturated adsorption capacities of the biologically and chemically synthesized schwertmannite were 117.0 and 87.0 mg·g−1, respectively. After exfoliation of the EPS from A. ferrooxidans, the biosynthesized schwertmannite displayed a “wool ball” shape, with rough particle surfaces, many microporous structures, and a larger specific surface area. The schwertmannite yield also increased by about 45% compared with that before exfoliation, suggesting that the secretion of EPS by A. ferrooxidans can inhibit the formation of schwertmannite.

scholarly journals Porosity model and pore evolution of transitional shales: an example from the Southern North China Basin

2020 ◽  
Vol 17 (6) ◽  
pp. 1512-1526
Author(s):  
Xiao-Guang Yang ◽  
Shao-Bin Guo
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Specific Surface Area ◽  
Mineral Content ◽  
High Specific Surface Area ◽  
High Porosity ◽  
Mechanical Compaction ◽  
Pore Evolution

AbstractThe evolution of shale reservoirs is mainly related to two functions: mechanical compaction controlled by ground stress and chemical compaction controlled by thermal effect. Thermal simulation experiments were conducted to simulate the chemical compaction of marine-continental transitional shale, and X-ray diffraction (XRD), CO2 adsorption, N2 adsorption and high-pressure mercury injection (MIP) were then used to characterize shale diagenesis and porosity. Moreover, simulations of mechanical compaction adhering to mathematical models were performed, and a shale compaction model was proposed considering clay content and kaolinite proportions. The advantage of this model is that the change in shale compressibility, which is caused by the transformation of clay minerals during thermal evolution, may be considered. The combination of the thermal simulation and compaction model may depict the interactions between chemical and mechanical compaction. Such interactions may then express the pore evolution of shale in actual conditions of formation. Accordingly, the obtained results demonstrated that shales having low kaolinite possess higher porosity at the same burial depth and clay mineral content, proving that other clay minerals such as illite–smectite mixed layers (I/S) and illite are conducive to the development of pores. Shales possessing a high clay mineral content have a higher porosity in shallow layers (< 3500 m) and a lower porosity in deep layers (> 3500 m). Both the amount and location of the increase in porosity differ at different geothermal gradients. High geothermal gradients favor the preservation of high porosity in shale at an appropriate Ro. The pore evolution of the marine-continental transitional shale is divided into five stages. Stage 2 possesses an Ro of 1.0%–1.6% and has high porosity along with a high specific surface area. Stage 3 has an Ro of 1.6%–2.0% and contains a higher porosity with a low specific surface area. Finally, Stage 4 has an Ro of 2.0%–2.9% with a low porosity and high specific surface area.

scholarly journals The Study of Specific Surface Area from Carbonat Rock Using Micro Computed Tomography (µ-CT)

2017 ◽  
Vol 1 ◽  
pp. 111-113
Author(s):  
Mahendra Risky Habibi ◽  
Thaqibul Fikri Niyartama
Keyword(s):  
Computed Tomography ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Calculation Result ◽  
Carbonate Rocks ◽  
Programming Algorithm ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
The Difference

Carbonate rocks have been scanned and reconstructed in order to get the value of specific surface area. We get it from the reservoir at a depth of 1000 metres in South Sumatra. Skyscan Micro-CT 1173 is used for throwing and thresholding images using Global Otshu to characterize rocks. Our calculation result shows that the value of specific surface area of carbonate rocks show results 100 to 10-2 using the programming Algorithm Fuzzy C-Mean. The difference in values far enough that it can be assumed that the carbonate rocks have a heterogeneous surface area. In addition, histogram model shows the similarity of the sample. The macro sample has the same characteristics as the micro sample.

scholarly journals Measuring the specific surface area of wet snow using 1310 nm reflectance

2014 ◽  
Vol 8 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
J.-C. Gallet ◽  
F. Domine ◽  
M. Dumont
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Volume Ratio ◽  
Liquid Water Content ◽  
Optical Methods ◽  
Integrating Sphere ◽  
Wet Snow ◽  
The Difference

Abstract. The specific surface area (SSA) of snow can be used as an objective measurement of grain size and is therefore a central variable to describe snow physical properties such as albedo. Snow SSA can now be easily measured in the field using optical methods based on infrared reflectance. However, existing optical methods have only been validated for dry snow. Here we test the possibility to use the DUFISSS instrument, based on the measurement of the 1310 nm reflectance of snow with an integrating sphere, to measure the SSA of wet snow. We perform cold room experiments where we measure the SSA of a wet snow sample, freeze it and measure it again, to quantify the difference in reflectance between frozen and wet snow. We study snow samples in the SSA range 12–37 m2 kg−1 and in the mass liquid water content (LWC) range 5–32%. We conclude that the SSA of wet snow can be obtained from the measurement of its 1310 nm reflectance using three simple steps. In most cases, the SSA thus obtained is less than 10 {%} different from the value that would have been obtained if the sample had been considered dry, so that the three simple steps constitute a minor correction. We also run two optical models to interpret the results, but no model reproduces correctly the water–ice distribution in wet snow, so that their predictions of wet snow reflectance are imperfect. The correction on the determination of wet snow SSA using the DUFISSS instrument gives an overall uncertainty better than 11%, even if the LWC is unknown. If SSA is expressed as a surface to volume ratio (e.g., in mm−1), the uncertainty is then 13% because of additional uncertainties in the determination of the volume of ice and water when the LWC is unknown.

scholarly journals The effective porosity and grain size relations in permeability functions

2014 ◽  
Vol 11 (6) ◽  
pp. 6675-6714 ◽  
Author(s):  
K. Urumović ◽  
K. Urumović
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Effective Porosity ◽  
Point Of View ◽  
Critical Conditions ◽  
Hydrogeological Parameters ◽  
Groundwater Flow Modelling

Abstract. Hydrogeological parameters of coherent and incoherent deposits are deeply dependent of their granulometric characteristics. These relations were shaped in formulas and defaultly used for calculation of hydraulic conductivity, and are valid only for uniform incoherent materials, mostly sands. In this paper, the results of analyses of permeability and specific surface area as a function of granulometric composition of various sediments – from siltey clays to very well graded gravels are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters which express an effect of forces operating fluid movement through the saturated porous media. Suggested procedures for calculating referential grain size and determining effective (flow) porosity result with parameters that reliably determine specific surface area and permeability. These procedures ensure successful appliance of Kozeny–Carman model up to the limits of validity of Darcy's law. The value of an effective porosity in function of referential mean grain size has been calibrated within range from 1.5 μm to 6.0 mm. Reliability of these parameters application in KC model was confirmed by very high correlation between predicted and tested hydraulic conductivity – R2 = 0.99 for sandy and gravelly materials and R2 = 0.70 for clayey-siltey materials. Group representation of hydraulic conductivity (ranged from 10-12 m s-1 up to 10-2 m s-1) presents coefficient of correlation R2 = 0.97, for total sum of 175 samples of various deposits. These results present the new road to researches of porous material's effective porosity, permeability and specific surface area distribution, since these three parameters are critical conditions for successful groundwater flow modelling and contaminant transport. From the practical point of view, it is very important to be able to identify these parameters swiftly, cheaply and very accurately.

Influence of processing on surface morphology and specific surface area for the nickel foam made by electrodeposition

2018 ◽  
Vol 14 (4) ◽  
pp. 735-743 ◽  
Author(s):  
B. Chen ◽  
Peisheng Liu ◽  
J.H. Chen
Keyword(s):  
Surface Morphology ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Design Methodology ◽  
Nickel Foam ◽  
Polymer Foam ◽  
Content Type ◽  
The Difference ◽  
Surface Morphologies

Purpose With the nickel foam made by the technique of electrodeposition on polymer foam, the purpose of this paper is to investigate the influence of several deferent processes on the surface morphology and the specific surface area of this porous product. Design/methodology/approach The surface morphologies of the nickel foam were examined by SEM. The specific surface area of the porous product was measured by gas (N2) permeability method and also calculated by the reported formula. Findings The nickel foam from sintering in NH3 decomposition atmosphere at 850°C will achieve the same specific surface area as that at 980°C, whether this porous structure after electrodeposition comes through direct sintering in NH3 decomposition atmosphere, or through burning in air at 600°C for 4 min beforehand then the same reductive sintering. Originality/value There have been some studies on the preparation and application of nickel foam, but few works focus on the processing influence on the specific surface of this porous product. The present work provides the investigations on the difference of the product made under different producing conditions, and the influence of several deferent processes on the specific surface area of the product.

Effects of clay type on soil hydraulic and mechanical properties - a global perspective

2020 ◽  
Author(s):  
Peter Lehmann ◽  
Ben Leshchinsky ◽  
Ben Mirus ◽  
Ning Lu ◽  
Surya Gupta ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Clay Fraction ◽  
Friction Angle ◽  
Soil Hydraulic ◽  
The Tropics ◽  
Clay Type

&lt;p&gt;Clay fraction affects soil hydraulic and mechanical properties and dominates specific surface area. Clay fraction is used for soil classification and in pedotransfer functions (PTFs) to estimate soil hydraulic functions from simpler soil properties (texture). Remarkably, despite large variations in composition and properties of clay minerals, PTFs use this attribute in undifferentiated manner, applied similarly to soils in the tropics dominated by Kaolinite and temperate soils with Montmorillonite. The large specific surface area of Montmorillonite compared to Kaolinite reduces both the soil hydraulic conductivity and the residual friction angle. We develop PTFs informed by clay-type via soil specific surface area effects on saturated hydraulic conductivity and residual friction angle. For friction angle, PTFs were fitted to experimental data using information on clay content and clay type. For hydraulic conductivity, analytical models based on surface area and particle size were adapted to capture conductivity data from different climatic regions. Global distributions of clay types are used to map soil specific surface area and related hydro-mechanical properties to improve land-surface models (especially in the tropics) and refine natural hazard risk assessment (landslides and debris flows).&lt;/p&gt;

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