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Reactive oxygen species (ROS) releasing materials are increasingly used in nanomedicines due to their effectiveness against a broad spectrum of microbes. However, most ROS‐releasing materials rely on external stimuli such as photoirradiation, either through photodynamic or photocatalytic processes, which limits their practical applications. Herein, this work presents a novel nanoclay mediated self‐promoted ROS releasing material called oxygen vacancies‐rich ZnO/kaolinite (Ov‐rich ZnO/Kaol). Both experiments and density functional theory (DFT) calculations reveal that the introduction of kaolinite increases the content of Ov in ZnO, and the change in the electronic structure promotes the process of oxygen adsorption and activation, resulting in the generation of ·O2−through oxygen reduction without photoirradiation. Molecular dynamics simulations confirm that Ov enhances the interaction between the material and bacterial membrane, promoting the bacterial‐killing effect of ·O2−. More importantly, Ov‐rich ZnO/Kaol is successfully prepared on a pilot scale and used to manufacture antibacterial gauze, which showed at least 99% antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in the absence of light. The as‐prepared material also exhibited satisfactory biocompatibility and biosafety. This method can offer a more benign approach to address the limitations of traditional photoirradiation‐dependent photosensitizers for antimicrobial gauze. [ABSTRACT FROM AUTHOR]

Green nanotechnology comprises the use of natural sources such as plant extracts as both reducing and stabilizing agents thereby reducing the reliance on hazardous chemicals. Recent breakthroughs in nanotechnology involve the incorporation of various metals to create mono and bimetallic nanoparticles, catalyzing transformative shifts. However, concerns arise due to the environmental impact of traditional synthesis methods. An alternative approach focuses on biosynthesized metal nanoparticles using clay, specifically Bentonite, MMT (Montmorillonite) and Kaolinite as supportive materials, emphasizing the prevention of agglomeration with clay and the use of plant extracts. The integration of clay, especially Bentonite, MMT and Kaolinite enhances the stability and functionality. The review emphasizes mitigating environmental impact by reducing metal ions and explores the use of phytochemicals fro environmentally friendly nanoparticle synthesis. Incorporating clay minerals not only improves synthesis efficiency but also minimizes the ecological footprint. Future research is expected to focus on integrative approaches in plant nanotechnology, particularly in agriculture and broader plant science. The comprehensive review covers literature from 2015 to 2023, providing systematic and interpretative data, highlighting progress and potential in eco-friendly metal nanoparticles synthesis supported on clay minerals. [ABSTRACT FROM AUTHOR]

Kaolinite was subjected to advanced exfoliation processes to form separated nano-silicate sheets (EXK) with enhanced physicochemical properties as adsorbents. This involved the incorporation of different exfoliating agents, urea (U/EXK), KNO3 (N/EXK), and CTAB (C/EXK), highlighting their impacts on their textural and surficial properties as adsorbents for safranin dye. The applied characterization techniques confirmed the higher exfoliating degree of C/EXK, followed by N/EXK and U/EXK. This appeared significantly in the determined surface area (55.7 m2/g (C/EXK), 36.7 m2/g (U/EXK), and 47.1 m2/g (N/EXK)) and adsorption performances. The C/EXK structure displayed a better safranin uptake capacity (273.2 mg/g) than N/EXK (231 mg/g) and U/EXK (178.4 mg/g). Beside the remarkable differences in textural properties, the advanced mathematical modeling and the corresponding steric and energetic parameters illustrate the mentioned uptake properties. The interface of C/EXK is highly saturated by active uptake sites (Nm = 158.8 mg/g) as compared to N/EXK (109.3 mg/g) and U/EXK (93.4 mg/g), which is in agreement with the characterization findings and the expected higher exposure of siloxane groups. Each of these sites can be filled with four dye molecules using C/EXK and N/EXK, which implies the vertical orientation of these adsorbed ions and the effective operation of multi-molecular mechanisms. The energetic (ΔE < 40 kJ/mol) and thermodynamic investigations indicate the spontaneous, physical, and exothermic uptake of safranin molecules by EXK particulates. These mechanisms might involve dipole bonding (2–29 kJ/mol), electrostatic attraction (2–50 kJ/mol), van der Waals forces (4–10 kJ/mol), and hydrogen bonding (<30 kJ/mol). [ABSTRACT FROM AUTHOR]

Organic compounds pose significant environmental concerns, including groundwater contamination. Clays are commonly used as liners to prevent contaminant permeation into the groundwater tables, necessitating an understanding of clay's behavior in the presence of organic compounds. The presence of organic contaminants results in changes in the dielectric constant of pore fluid, which influences the interparticle energies and double layer thickness in the soil-pore fluid system. This study aims to elucidate the mechanisms of these changes by examining the response of smectite and kaolinite to variations in the dielectric constant. Experimental tests, including Atterberg limits, unconfined compression strength, water adsorption, sedimentation, pH, and XRD, were performed on clay samples at different concentrations of water-isopropyl alcohol mixtures. Results indicate that smectite exhibits higher Atterberg limits and water adsorption capacity compared to kaolinite. Smectite also shows more pronounced changes in response to decreasing dielectric constant. Conversely, changes in kaolinite's behavior were attributed to variations in pore fluid viscosity and dipole moment. These findings emphasize the importance of considering viscosity and dipole moment alongside dielectric constant in predicting kaolinite behavior. Overall, this study enhances the understanding of how variations in pore fluid dielectric constant affect the geotechnical and geo-environmental behavior of smectite and kaolinite. [ABSTRACT FROM AUTHOR]

Clay and clay-based minerals have attracted research attention because of their unique properties and a vast range of applications in industry. In order to assess the potential applications, four different processed local kaolin-based raw minerals were collected from the Aral Sea region of Uzbekistan, and the total mineralogical properties have been explored. The results reveal that the structural, vibrational and electronic properties of metakaolinites only slightly differ from those of kaoline. The presence of corundum, quartz and kaolinite structural phase in minerals was determined by XRD analysis. FTIR and Raman studies expose the primary peaks which are associated with the functional groups of Al–OH, Al–O and Si–O in higher-frequency stretching and lower-frequency bending modes. The elemental and chemical compositional (XRF and XPS) analysis demonstrates the presence of major elements (Al, Si, Na, Fe, Ti) in the raw mineral and other metal contaminations (Mg, Ca, S, Cr, Zr). The SEM analysis demonstrates the morphological nature of kaolin-based raw minerals that can be exploited for industrial purposes. [ABSTRACT FROM AUTHOR]

ABSTRACT In this work, we present a simple method for the pyrofabrication of a new kaolinite‐ silver oxide quantum dots nanocomposite (Kao‐Ag2O/QDs) that is used for the degradation of rhodamine B (RhB) and indigo carmine (IC) dyes. A homogenous combination of kaolinite and silver nitrate was sintered up to 350 °C to create the extremely effective photocatalyst (Kao‐Ag2O/QDs). Various analytical techniques were employed to characterize the Kao‐Ag2O/QDs photocatalyst such as XRD, FTIR, XPS, SEM–EDX, TEM, DTA/TGA, ZP, BET, and UV–Vis DRS. The degradation of RhB and IC dyes through the photocatalyst was carried out in aqueous solutions utilizing several pH dye solutions and sustainable solar energy in atmosphere conditions. The nanocomposite that was prepared had shown an enhanced specific surface area of 53.3005 m2/g, a pore size of 8.1197 nm, and a total pore volume of 0.216 cm3/g. It also displayed an optical band gap energy of 2.9 eV. The study creates that employing the ideal dose of 2000 and 1500 mg/L of the Kao‐Ag2O/QDs photocatalyst at neutral conditions (pH = 7) resulted a maximum degradation effectiveness of RhB and IC of 91.06 and 93.46% after 90 min, respectively. RhB and IC dyes degradation followed Langmuir first‐order kinetics with a rate constant of 0.0217 and 0.0216 min−1 at pH = 7, respectively. The photocatalytic degradation activity for RhB dye is based on hydroxyl radicals (˙OH) and superoxide radicals (˙O2−), while the mechanism of IC removal is based on superoxide radicals (˙O2−), as revealed by scavenger‐based radical trapping studies. A triple reusability study found that the Kao‐Ag2O photocatalyst is highly stable with degradation efficiencies of RhB and IC dyes from the initial 91.09 to 90.04, 88.54, and 86.27% and from the initial 93.46 to 92.8, 91.4 and 89.32%, respectively. The optimal situations for the parameters were identified by the Box–Behnken design (BBD), which was well matched with photocatalytic degradation tests. [ABSTRACT FROM AUTHOR]

Compared with conventional lithium‐ion battery systems, anion‐intercalation in graphite cathodes opens avenues for the development of batteries with groundbreaking power density. This study explores the enhancement of dual‐ion batteries (DIBs) by gel polymer electrolyte (GPE) enhanced with surface‐charged nanoclays, focusing on overcoming traditional challenges such as electrolyte decomposition, anion‐solvent co‐intercalation, and interfacial instability at the graphite cathode. Three nanoclays including montmorillonite, kaolinite, and halloysite are compared by incorporating them into GPE and evaluating their effect on the electrochemical properties, ion conduction, and mechanical integrity of DIBs. Particular attention is paid to the halloysite because of its differential internal and external surface charges, which generate charge separation, facilitate optimal lithium‐ion transport, and mitigate undesirable anion‐solvent interactions. These results indicate that halloysite‐incorporated GPE (HS‐G) significantly improves DIB performance, as demonstrated by extended cycle life, robust capacity retention at fast charge/discharge rates of 20 C, and operational stability over a wide temperature range (0–60 °C). These improvements are attributed to the unique structural advantages of HS‐G, including effective charge separation, enhanced anion diffusion, and reduced solvent co‐intercalation, which provide an environmentally friendly and cost‐effective approach to advanced DIB applications. [ABSTRACT FROM AUTHOR]

The thermally activated clay minerals are well-known as perspective supplementary cementing materials (SCMs) able to reduce the Portland clinker consumption and thus also the related CO2 emissions. The best SCM performance among clay minerals is provided by thermally activated kaolin (metakaolin). Nevertheless, kaolinitic clays are not available everywhere, while varying mixed clays can be considered as globally affordable raw materials. The present work deals with the thermal activation of four illitic-kaolinitic clays with varied content of clay minerals, quartz and calcite, available locally in the Czech Republic. The attainment of activation was evaluated with the help of mechanical strength and the saturated lime test. There is no doubt that kaolin is the best clay for SCM production. However, the activation of mixed illitic-kaolinitic clays at 600 °C provided comparable and sufficient performance, despite that the crystal structure of illite was not completely decomposed. The non-clay minerals presence did not reduce the activity either; even the clay containing just about 50% of clay minerals (mostly illite) treated at 650 °C provided sufficient mechanical performance. As the drawback of activated illitic clays must be considered their higher sensitivity to the proper calcination temperature compared to metakaolin since illite (and other 2:1 clay minerals) does not form any metastable dehydroxylated phase. [ABSTRACT FROM AUTHOR]

Restoration of historical buildings requires an application of suitable and convenient materials which are compatible with historical legacy. On the other hand, the used materials have to show adequate durability and fulfil current tendencies of environmental-friendliness policy. Most historical buildings have their facades made of lime-based, or more precisely, blended-lime-based plasters. Metakaolin belongs to one of the most common representatives of pozzolanic admixtures used in this field. It is an artificial product, which arises by the calcination of kaolinitic clay or claystone at temperatures of about 550–900 °C. Like every other production process, a remarkable amount of waste rises also in the case of metakaolin. This study is aimed at the utilization of this waste, specifically the waste calcined shale (WCS). It is composed of not properly burned particles with varying compositions. Contrary to metakaolin, it contains a lower amount of amorphous phase and a higher amount of kaolinite and mullite. WCS was used in the production of lime-based plasters with a dosage of up to 50%. During the hardening, the carbonation process takes place in combination with the pozzolanic reactions. It gives rise to a higher amount of amorphous structures, about 15% in the case of pure lime contrary to up to 45% (in the highest dosage of WCS) and other crystal phases such as calcium-aluminate-carbonate hydrates. Obtained phase analyses are supported by the determination of SEM analysis and mechanical properties, which are also measured depending on time. [ABSTRACT FROM AUTHOR]

A systematic simulation study was performed to investigate the interlayer interactions in a 1:1 layered phyllosilicate clay, kaolinite. Atomistic simulations with classical realistic force fields (INTERFACE and ClayFF) were used to examine the influence of the individual non-bonded interactions on the interlayer binding in the kaolinite model system. By switching off selected pairwise interactions in the applied force fields (leaving the intralayer interactions intact), it was confirmed that the tetrahedral–octahedral-type pairwise interactions held the kaolinite plates together and that interlayer hydrogen bonding, modeled by Coulombic forces, played a dominant role in this. Furthermore, it was observed that the number of hydrogen bonds formed had a significant influence on the basal spacing, and thus there was a striking change in the layer–layer interaction strength when there were only two kaolinite plates in the system, rather than several plates, as in real kaolinite particles. Contrary to expectations, the dispersion forces of the studied force fields alone were found to be strong enough to hold the kaolinite plates together. [ABSTRACT FROM AUTHOR]

The current study investigates the effect of adding a low-cost biomaterial (sawdust biomass) to kaolinite clay on the properties of insulating refractory materials. Natural kaolinite clay from NW Tunisia has been selected for porous ceramic preparation due to its high alumina content (23.64%) with low impurities, especially iron and alkaline oxides. For this study, a set of cylindrical samples were prepared from mixtures of Tabarka clay with different proportions of sawdust (10, 15 and 20%). Those green specimens were pressed and sintered to 1350 °C for 2h. Experimental data showed that the increase in sawdust proportion increased the open porosity from 24 to 35%. SEM images showed higher important porosity with higher biomass addition. Similarly, bulk density and compressive strength decreased to 1.65 g/cm³ and 17 MPa, respectively. Mullite phase was also generated by the abundant alumina and silica in the raw feed. Several ceramic specimens were also manufactured under optimal conditions: sawdust (20%), pressure (10 kN), and sintering at 1200, 1250 and 1300 °C. The obtained ceramics showed higher porosity (57%), but lower bulk density (1.13 g/cm³). These are the required standards for silica-alumina insulating materials, confirming the possible valorization of kaolinite clay from Tunisia for refractory insulating ceramic. [ABSTRACT FROM AUTHOR]

This study uses coal ash obtained from the Tanjung Bin coal power plant consisting of a mixture of fly ash and bottom ash at different ratios. Such mixtures will be used with the minimum amount of Ordinary Portland Cement to stabilise marine clay. Compaction data corresponding to a mixture of coal ash and OPC mixed with marine clay soil provides 1535 and 1600 kg/ m 3 MDD and 18–22.2% OMC ranges, as additive percentages are increased. The unconfined compressive strength test indicated the highest increase at 50BA:50FA ratio with a value of 536 kPa at 15% of additive. The strength of the treated soil sample would also increase with increasing additive percentage and curing period. The XRD of untreated soil sample indicates composition intensity for minerals like quartz, mica, kaolinite, calcite, montmorillonite, and muscovite generally decreased with curing time; on the other hand, halloysite composition reduced. However, a new mineral is formed: calcium aluminium silicate hydroxide hydrate. Moreover, the FESEM results show that the treated marine clay surface particles looked denser with time. Structural voids were also reduced. In line with the XRD and FESEM test outcomes, the EDX results indicated that the formed cementitious products comprised calcium aluminate silicate hydrate. [ABSTRACT FROM AUTHOR]

Using a complex of analytical methods, clay minerals were studied in Pleistocene sediments from Hole ODP 1038B (120.50 m deep), drilled on the northwestern edge of the Central Hill (Escanaba Trough, Gorda Ridge) near the hydrothermal source with a temperature of 108°C, as well as in Pleistocene background terrigenous sediments from reference Hole ODP 1037B, drilled in the Escanaba Trough 5 km south of the Central Hill. The terrigenous clay mineral assemblage in sediments from Hole 1037B consists of the mixed-layer smectite-illites, smectite, chlorite, illite, and kaolinite. Sediments from Hole 1038B in the interval from the bottom surface to a depth of 5–7 m are composed of terrigenous clay minerals. In the rest of the sedimentary section, clay minerals are represented by the newly formed biotite, chlorite, and dioctahedral smectite. They were formed during the basaltic melt intrusion into the Escanaba Trough with the formation of a laccolith and the subsequent rapid cooling of its flank. The intrusion was accompanied by the ascent of high-temperature hydrothermal fluid in the central discharge channel, interacting with the adjacent sediments. As a result, the fine-dispersed biotite was formed in sediments at the high-temperature stage of this interaction due to the primary terrigenous clay minerals, K-feldspar, and amphiboles. The rapid cooling of the hydrothermal fluid to a temperature of presumably 270–330°C promoted the partial replacement of biotite by chlorite. The further rapid cooling of the hydrothermal fluid to 200°C and lower and its mixing with seawater seeping into sediments of the Central Hill fostered the formation of smectite. [ABSTRACT FROM AUTHOR]

The injection of CO2 into deep, unmineable coal seams is an effective strategy for reducing greenhouse gas emissions. At depths greater than 800 m, the carbon dioxide transitions to the supercritical state (Sc-CO2). This study investigated the complex interactions between Sc-CO2 and coal, which substantially affected the pore structure, mineralogy, and permeability of the coal. We used low-pressure nitrogen gas adsorption (LP-N2GA) to assess the impact of Sc-CO2 on the pore characteristics of the coal. X-ray diffraction (XRD) was also used to determine the causal factors. We performed comparative triaxial permeability tests before and after Sc-CO2 exposure to evaluate the changes in permeability for various coal types. Our findings suggested that Sc-CO2 exposure markedly increased the complexity of the coal pore structure, which in turn affects coal-rock permeability. Specifically, a 10-day exposure period resulted in considerable increases of 43.5% and 50.9% in the pore volume and the specific surface area, respectively, along with a slight increase of 0.01 nm in the average pore diameter. Furthermore, there were notable decreases in the contents of minerals such as kaolinite, calcite, and pyrite, with decreases of 1.5%, 2.8%, and 2.2%, respectively, whereas the quartz content increased by 3%, indicating that significant mineral dissolution influenced the pore structure. A significant positive correlation was observed between the loss of coal mass and the increase in permeability. The effects of Sc-CO2 were most pronounced in coals with low permeabilities, particularly during the initial phase of saturation. Subsequent saturation cycles and prolonged exposure resulted in a reduced rate for permeability enhancement, which eventually reached a plateau. This study underscores the critical role of Sc-CO2 in long-term geological CO2 storage and improved efficiency for coalbed methane production. [ABSTRACT FROM AUTHOR]

This study describes the nondestructive testing and evaluation of different clay–lime composites by real-time impedance spectroscopy (IS) monitoring of lime hydration and cementation mechanisms. The experimental investigations were carried out on two different clays, white clay (with predominantly kaolinite mineralogy) and brown clay (with predominantly montmorillonite mineralogy), to determine the influence of clay mineralogy on the fate of lime stabilization processes in different soils. Additionally, the effects of key influencing parameters such as lime content, curing period, and curing temperature were assessed. The time-dependent electrical impedance behavior of different clay–lime systems was determined in terms of bulk resistance and interfacial capacitance, obtained by equivalent circuit modeling of the impedance spectra. The variations in the electrical impedance properties showed a strong correlation with unconfined compressive strength (UCS) of different clay–lime composites. Further, the microstructural improvement of various clay–lime composites was determined with the aid of scanning electron microscopy, mercury intrusion porosimetry, and thermogravimetric analysis to get an auxiliary interpretation of the electrical impedance spectroscopy (EIS) results. The time-dependent variations of the soil impedance evidently manifested the continuous chemical and morphological evolution of the different clay–lime systems during the curing process at different thermal conditions by the formation and deposition of cementitious calcium-silicate-hydrates (C-S-H) and calcium-aluminate-silicate-hydrates (C-A-S-H) compounds. Overall, the nondestructive impedance spectroscopy technique has been proven effective in describing the microstructural changes and related mechanical improvement of lime-treated soils. Although the use of this technique seems to be inefficient for a field quality control assessment, the analysis of the electrical parameters calculated from the impedance spectra measured gives a comprehensive idea of the evolution in the chemically stabilized soil material. [ABSTRACT FROM AUTHOR]

This paper gives an overview of various factors that influences the performance of Limestone Calcined Clay Cement (LC3) concrete. Among the various research related to ternary cements, this paper discusses the influential factors, based on the strength and durability aspects. The factors such as the type and purity of kaolinite, limestone, gradation of the limestone, concentration of gypsum, calcined clay, limestone ratio, clinker content, water-to-binder ratio, method and effect of calcination, grinding criteria, optimum temperature of calcination, calcined clay content, method of curing and other factors are interpreted. Even low-grade materials with minimum purity have also been found to achieve the desired properties. Therefore depending upon the knowledge of the importance of every parameter, the best quality concrete could be developed with the available source and facilities. With the available quality and quantity of material, sustainable ternary cement could be obtained. By optimizing the various factors that influence the behavior of LC3 concretes, more economical and durable concrete can be produced. [ABSTRACT FROM AUTHOR]

This study investigated the physicochemical effects of kaolinite (CK) and montmorillonite (CM) calcined clays on the sulfate balance, early hydration, and artificial pore solution of limestone calcined clay cement (LC3). The effects of fineness, clay dissolution, and ion-adsorption capacity were evaluated by isothermal calorimetry, compressive strength, ICP-OES, and zeta potential within 72 h, respectively. Increasing the fineness of both calcined clays did not significantly affect the sulfate depletion kinetics or the compressive strength and the adsorption of Ca2+ ions onto the calcined clay's surface is not the main factor responsible for differences in sulfate demand. The higher dissolution of ions Al in CK provided an intensified and accelerated formation of ettringite that competes for the available sulfate. We demonstrate that the chemical effects have a significant impact on the sulfate balance of LC3, revealing the lesser impact of alternative clays like montmorillonite compared to metakaolin (MK) which can minimize the problem of accelerated sulfate depletion of LC3 mixes with MK. [ABSTRACT FROM AUTHOR]

Limestone calcined clay cement (LC3) is emerging as an alternative to Portland cement, offering economic advantages, reduced CO2 emissions, and mechanical properties on par with Portland cement. Central to the effective utilization of LC3 is understanding how the fineness of its components affects its performance. The current study investigates limestone calcined clay cement mixtures composed of kaolinite, illite, and montmorillonite calcined clays and limestone at two levels of fineness. Strengths of mortar cubes were tested at 1, 3, 7, and 28 d and statistical analysis was performed with a 95% confidence level. Additionally, LC3 pastes were analyzed using x-ray diffraction, mercury intrusion porosimetry, scanning electron microscopy, and isothermal calorimetry. The fineness of the calcined clay along with the fineness of limestone is found to be statistically significant for 28-d strength in LC3 mortars made with kaolinitic and montmorillonite calcined clays. All hydrated blends had a hemicarboaluminate phase, whose intensity was related to the fineness of the calcined clay, and the monocarboaluminate phase formation was found to be dependent on both the fineness and type of calcined clay. Porosimetry revealed that LC3 pastes with illite clay have larger threshold pore diameters than those with kaolinite clay. LC3 pastes containing kaolinite have denser microstructures due to C–S–H and hemicarboaluminate formation. Pastes produced with coarse calcined clay and coarse limestone led to a broader, weaker heat development peak and lower normalized cumulative heat. LC3 with kaolinitic clay has the highest normalized cumulative heat, while that with montmorillonite calcined clay has the lowest. [ABSTRACT FROM AUTHOR]

Argillaceous rocks constituting clay fractions are potential host rock candidates for isolation of radioactive waste in underground repositories. The present study aims at characterization of two argillaceous rocks (shales) from different geological settings (surface and subsurface localities) and investigation of their cesium (Cs) sorption behaviour. The shales were characterized using various analytical techniques to evaluate the textural attributes, mineralogical constituents and surface properties. The major mineralogical constituent of the surface and subsurface shale was quartz (62%) and kaolinite (56%), respectively. The abundance of smectite and illite in both the shales was comparable. Fluorescence and UV-Vis spectra confirmed the presence of polyaromatic hydrocarbons (PAHs) in the subsurface shale. The subsurface shale demonstrated higher Cs retention (17 mg g−1) than the surface shale (12 mg g−1) due to higher kaolinite content. Surface analysis of the shale samples revealed involvement of ion exchange mechanism in Cs uptake. The agreement of experimental results with Freundlich sorption isotherm suggests the heterogenous nature of the shales with multiple sorption sites. The correlation of geochemistry (especially the kaolinite content) for both the shales with Cs sorption is clearly highlighted in the present studies. The present investigation implies the applicability of the studied shales for waste management applications. [ABSTRACT FROM AUTHOR]

The use of cementitious materials to improve clay is a common technique in engineering. However, the effectiveness of these materials, particularly desulfurized gypsum, on clays with different mineral compositions remains unclear, resulting in a lack of theoretical basis for their application in engineering. This study investigated the synergistic effects of clinker–metakaolin–desulfurized gypsum on clays with various mineral compositions through a series of macroscopic and microscopic laboratory tests. The results revealed that the stress–strain relationships of all clay samples exhibited softening characteristics. The softening was most pronounced in kaolinite samples, followed by illite and bentonite samples. For single-phase clays, the unconfined compressive strength followed the order of kaolinite > illite > bentonite. For multiphase clays, the order was illite + kaolinite > bentonite + illite + kaolinite > bentonite + kaolinite > bentonite + illite. The strength enhancement in the improved soils was primarily due to kaolinite and illite. As the content of desulfurized gypsum increased, the ettringite crystals in the improved soils transformed from cluster-like to framework-like structures. When the gypsum content exceeded 10%, the macroscopic performance of the improved soils decreased. These findings provide valuable insights for related engineering applications. [ABSTRACT FROM AUTHOR]

One of the major environmental problems in hot and arid locations is the production of dust. This study presents green slurries based on nanoclay—and blast furnace slag for stabilizing desert sands. The slurries introduced contain bentonite and kaolinite mineral nanoclays, along with blast furnace slag powder. Unconfined compressive strength, moisture content, and wind tunnel tests were conducted to evaluate the performance of the compounds in stabilizing sand and increasing its water-holding capacity. The mass percentages of bentonite nanoclay and blast furnace slag in the stabilizer slurry were optimized at 1–3% and 1–5%, respectively. The optimized mass percentages of kaolinite nanoclay and blast furnace slag slurry were 1–1% and 3–1%. The study found that soil stabilized with slurries increased compressive strength by three times compared to unstabilized soil. Additionally, the addition of stabilizers improved soil moisture retention by 50%. Sand surfaces stabilized with nanoclays and slag demonstrated excellent resistance to wind erosion, even at wind speeds of up to 100 km/h. Furthermore, there was no wind erosion observed at 60 °C. The suggested slurry compounds have shown a strong ability to enhance the mechanical properties of soil, increase soil water retention, and reduce wind erosion of sandy soil. [ABSTRACT FROM AUTHOR]

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We use the crystallinity of hydrated silica, represented by the 1.4 μm absorption position in orbiter spectroscopic data, as a proxy for the longevity of water–rock interaction in the Syrtis Major region. Geological maps and crater size–frequency distribution analyses are employed to contextualize mineral detections and estimate surface ages. Hydrated silica is detected within two distinct geological units: a younger "volcanic terrain" (vt) unit (∼2.4 Ga) and an older "highland terrain" (ht) unit (3.5–3.7 Ga). Hydrated silica in the vt unit typically has a band position <1.41 μm, consistent with amorphous opal‐A, suggesting these younger terrains have experienced limited interaction with water. In contrast, hydrated silica in the older highlands typically has a band position >1.41 μm, indicating opal‐CT, suggesting that these deposits have had more time to interact with water, while also producing accessory minerals such as kaolinite and Fe/Mg phyllosilicates. Plain Language Summary: This study explores the interactions between water and rocks in a region on Mars known as Syrtis Major by investigating a mineral‐like substance called hydrated silica. The structure of hydrated silica helps us estimate the extent of water interaction and its effects on the rocks. We used satellite data to locate this mineral across Syrtis Major and infer its crystal structure. Furthermore, we developed detailed geological maps and estimated surface ages to understand the geological context. We found that hydrated silica is located in two different types of areas: (a) a younger volcanic region; and (b) an older highland region. In the younger volcanic areas, it appears that less crystalline hydrated silica formed by interaction with small amounts of water, possibly during later volcanic activity. In the older highlands, more crystalline hydrated silica likely interacted with water for a longer duration or in larger amounts. This information aligns with the idea that the older highlands experienced more extensive or long‐lasting interactions with water compared to the younger volcanic regions. It provides insights into different wet periods in Mars' past, aiding our understanding of the planet's geological history and the role water played in shaping its surface. Key Points: We analyzed the crystallinity of hydrated silica in Syrtis Major to infer the extent and longevity of water–rock interactionAmorphous silica is found in young volcanic terrains within Nili and Meroe Paterae and more crystalline silica in the older highlandsOlder highland regions likely underwent a longer interaction with water compared to younger volcanic terrains [ABSTRACT FROM AUTHOR]

Several borehole cores intersecting faults related to coseismic slip display high‐temperature features, including thermal decomposition of fault gouge. We present evidence that these features may be related to fluid drainage of the slip zone during seismic slip. We sheared water‐saturated kaolinite powders under both fluid drained and undrained conditions, expected for seismic slip at shallow crustal depths. Our results show typical dynamic weakening behavior regardless of conditions. Under fluid drained condition, restrengthening accompanied by the thermal decomposition of kaolinite occurs. In addition, thermal decomposition of kaolinite tends to be initiated at high normal stresses (>5 MPa) with short displacement (<5 m). We propose that thermal pressurization acts as a weakening mechanism but ceases because of fluid drainage, triggering kaolinite thermal decomposition. This finding explains seismic‐slip‐related clay anomalies at depth rather than at the surface, as observed in the borehole after the 1999 Mw 7.6 Chi‐Chi earthquake, Taiwan. Plain Language Summary: Seismic faulting at depth can drive thermochemical reactions within the slip zone, given the high slip velocity and large displacement. Several slip‐zone samples from deep drilling projects following catastrophic earthquakes have exhibited high‐temperature geological characteristics, which were not present in fault zone outcrops hosting surface ruptures. We sheared kaolinite (as an analogue of fault zone materials) under both fluid drained and undrained conditions, simulating conditions expected during seismic slip at borehole depths. Our results show that, regardless of the applied conditions, the materials tend to weaken dramatically during shearing. However, when fluids are allowed to drain from the slip zone, there is a subsequent strengthening accompanied by the thermal decomposition of kaolinite. We suggest that thermal pressurization operates as the weakening mechanism but is ceased due to fluid drainage, resulting in the thermal decomposition of kaolinite gouges. In addition, the thermal decomposition of kaolinite tends to be triggered at large normal stresses. Because kaolinite is a common component in both fault zones and subduction zones at shallow depths, our findings have potential implications for reported thermally driven reactions within slip zones as a potential seismic indicator at shallow crustal depths. Key Points: Thermal pressurization operates as the dynamic weakening mechanism during experimental seismic slip regardless of the ambient conditionsThermal pressurization ceases because of fluid drainage and is followed by kaolinite thermal decompositionThermal decomposition of kaolinite tends to be initiated at large normal stresses in the seismic slip range [ABSTRACT FROM AUTHOR]

This research investigates the mechanical activation of kaolin as a supplementary cementitious material at the laboratory scale, aiming to optimize milling parameters using the response surface methodology. The study evaluated the effects of rotation speed and milling time on the amorphous phase content, the reduction in crystalline kaolinite, and impurity incorporation into the activated clay through the Rietveld method. The results demonstrated that adjusting milling parameters effectively enhanced clay activation, which is crucial for its use in low-carbon cements. High rotation speeds (300/350 rpm) and prolonged grinding times (90/120 min) in a planetary ball mill increased the pozzolanic activity by boosting the formation of amorphous phases from kaolinite and illite and reducing the particle size. However, the results evidenced that intermediate milling parameters are sufficient for reaching substantial degrees of amorphization and pozzolanic activity, avoiding the need for intensive grinding. Exceedingly aggressive milling introduced impurities like ZrO2 from the milling equipment wear, underscoring the need for a balanced approach to optimizing reactivity while minimizing impurities, energy consumption, and equipment wear. Achieving this balance is essential for efficient mechanical activation, ensuring the prepared clay's suitability as supplementary cementitious materials without excessive costs or compromised equipment integrity. [ABSTRACT FROM AUTHOR]

Limestone calcined clay cement (LC3) presents a promising alternative material due to its reduced CO2 emissions and superior mechanical properties compared to traditional Portland cement (PC). This study investigates the synergistic effect of calcined coal-series kaolinite (CCK) and limestone (LS) on the hydration behavior of cement, specifically focusing on varying mass ratios. The combination of CCK and LS promotes the formation of strätlingite and carboaluminates, which enhances early-age strength development. Additionally, the inclusion of CCK facilitates the formation of carboaluminates during later stages of hydration. After 56 days of hydration, the content of carboaluminates is over 10%wt. This stimulation of secondary hydration products significantly refines the evolution of pore structure, with the harmful large pores gradually transformed into harmless medium pores and gel pores, leading to marked improvements in compressive strength from 7 to 28 days. Replacing 45% PC with CCK and LS at mass ratio of 7 to 2, the compressive strength of blends reaches 47.2 MPa at 28 days. Overall, the synergistic interaction between CCK and LS presents unique opportunities to minimize the CO2 footprint of the cement industry without compromising early and long-term performance. [ABSTRACT FROM AUTHOR]

Large clastic dykes (the Harutori‐Taro and Harutori‐Jiro dykes) and smaller dykes are exposed in the underground Kushiro Coal Mine (KCM), Japan. This study examines these dykes as a case study to investigate the geological conditions and fluid flow history that lead to the development of large clastic dykes in basins. The composition of the dykes indicates the Beppo and/or Harutori formations as their parent unit. Crystallite size distribution (CSD) analysis reveals Ostwald ripening of the kaolinite in the kaolinitised feldspar from the dykes, suggesting stagnant conditions in the parent unit before the dyke was formed. In contrast, smectite CSDs and the high carbonate content of the dykes suggest that large volumes of fluid flowed through the dykes along the established hydraulic gradient, which was triggered by the breaking of the upper seal. The isotopic and chemical compositions of the calcite and aragonite in the dykes, with moderate siderite and rhodochrosite content, indicate the fluid was a warm (>30°C) mixture of freshwater and saltwater, which was transferred from deeper levels of the parent unit towards the crest of an anticline. Immediately after sand injection, the semi‐closed system of the parent unit near the root of the large dyke was transformed into a major flow channel for overpressurised fluids. Subsequently, a large volume of fluid flowed along the vertical conduit (or dyke) over a long period of time (>1 Myr), which removed fluid from a widespread area (i.e., several hundred square kilometres) of the basin. The results show that thin parent units, poor lateral continuity of the upper seal, and spatially heterogeneous overpressurisation do not preclude the formation of large dykes. [ABSTRACT FROM AUTHOR]

The adsorption behavior of NH4+ and Mg2+ at kaolinite surfaces was investigated by using molecular dynamics (MD) simulations, considering the factors such as ion concentration, NH4+/Mg2+ mixing ratio, and layer charge of kaolinite. The results showed that the increase in ion concentration did not affect the adsorption modes of NH4+ and Mg2+ ions but promote the increase in the adsorption capacity. The total adsorption capacities of Mg2+ and NH4+ were 3.25 × 10−6 and 2.85 × 10−6 μmol·mm−2 at the ion concentration of 1.5 mol·L−1, respectively. When NH4+ and Mg2+ were co‐adsorbed, they could inhibit the adsorption of each other at the surface of kaolinite, except that the inner‐sphere (IS) adsorption of NH4+ at aluminum hydroxyl (Al–OH) surface could be enhanced by the presence of Mg2+. Both NH4+ and Mg2+ tended to adsorb at the siloxane (Si–O) surface of kaolinite rather than Al–OH surface. When layer charge occurred in kaolinite, a small number of Mg2+ began to adsorb in the IS complexes at 1.7 and 2.3 Å above the Al and O atoms of the lattice‐substituted tetrahedra of the Si–O surface, and at 1.7 Å above the hexahedra of the Al–OH surface. However, most of NH4+ were adsorbed in IS complexes at 1.7 Å above the center of the oxygen six‐membered ring of the Si–O surface and above the hexahedron of the Al–OH surface. The adsorption capacity of Mg2+ changed little with the increase of layer charge density, while the IS and total adsorption capacity of NH4+ increased significantly. [ABSTRACT FROM AUTHOR]

The adsorption of trihalomethanes (THMs) from drinking water was investigated in the current study through comparison studies of kaolinite and ZnO@kaolinite nanocomposites. The clay structural network’s successful immobilization on the zincite hexagonal structure of ZnO nanoparticles’ lattice layers was verified by the SEM/EDX analysis. Under the optimum conditions, the maximum removal of THMs was achieved by kaolinite and ZnO@kaolinite nanocomposites after 60 min. The adsorption performance of the ZnO@kaolinite nanocomposites was greater than that of kaolinite because the former had a larger surface area than the latter. The Freundlich isotherm model best matched the adsorption experimental data, which also reveals the existence of multilayer adsorption on a diverse surface with the greatest correlation (R² ¼ 0.956 and 0.954, respectively) for both nanoadsorbents using the pseudo-first-order (PFO), pseudo-second-order (PSO), mixed 1, 2-order (MFSO), and intraparticle diffusion (IPD) models. The mechanism by which THMs in drinking water adsorb onto nanoadsorbents was examined. This revealed that both intraparticle and film diffusion were involved in the adsorption process. Kaolinite and ZnO@kaolinite nanocomposites can be used in water treatment to remove THMs due to their great recyclable and reusable properties, even after six cycles. [ABSTRACT FROM AUTHOR]

Nanoclay, a processed clay, is utilized in numerous high-performance cement nanocomposites. This clay consists of minerals such as kaolinite, illite, chlorite, and smectite, which are the primary components of raw clay materials formed in the presence of water. In addition to silica, alumina, and water, it also contains various concentrations of inorganic ions like Mg2+, Na+, and Ca2+. These are categorized as hydrous phyllosilicates and can be located either in interlayer spaces or on the planetary surface. Clay minerals are distinguished by their two-dimensional sheets and tetrahedral (SiO4) and octahedral (Al2O3) crystal structures. Different clay minerals are classified based on the presence of tetrahedral and octahedral layers in their structure. These include kaolinite, which has a 1:1 ratio of tetrahedral to octahedral layers, the smectite group of clay minerals and chlorite with a 2:1 ratio. Clay minerals are unique due to their small size, distinct crystal structure, and properties such as high cation exchange capacity, adsorption capacity, specific surface area, and swelling behavior. These characteristics are discussed in this review. The use of nanoclays as nanocarriers for fertilizers boasts a diverse array of materials available in both anionic and cationic variations. Layered double hydroxides (LDH) possess a distinctive capacity for exchanging anions, making them suitable for facilitating the transport of borate, phosphate, and nitrate ions. Liquid nanoclays are used extensively in agriculture, specifically as fertilizers, insecticides, herbicides, and nutrients. These novel nanomaterials have numerous benefits, including improved nutrient use, controlled nutrient release, targeted nutrient delivery, and increased agricultural productivity. Arid regions face distinct challenges like limited water availability, poor soil quality, and reduced productivity. The addition of liquid nanoclay to sandy soil offers a range of benefits that contribute to improved soil quality and environmental sustainability. Liquid nanoclay is being proposed for water management in arid regions, which will necessitate a detailed examination of soil, water availability, and hydrological conditions. Small-scale trial initiatives, engagement with local governments, and regular monitoring are required to fully comprehend its benefits and drawbacks. These developments would increase the practicality and effectiveness of using liquid nanoclay in desert agriculture. [ABSTRACT FROM AUTHOR]

Comprehending water molecules adsorption mechanism on clays is crucial to hydraulic fracturing technology application in clay-rich shale formation. In this research, the adsorption of water vapor on non-swelling of kaolinite (Kaol), swelling clay of montmorillonite (Mt), and their three different mixtures (75:25/Mt:Kaol, 50:50/Mt:Kaol and 25:75/Mt:Kaol) was studied. The effect of mixing ratio of Mt and Kaol on the adsorption process of water vapor was discussed. The obtained findings display that the swelling clay of Mt possesses the greater water vapor adsorption ability than the non-swelling clay of Kaol. Enhancing the mass ratio of Mt in the mixture can obviously improve the uptake for water vapor. For Mt, primary adsorption exhibits a more apparent effect on the adsorption of water vapor adsorption. For Kaol, the effect of secondary adsorption on water vapor adsorption is more significant. With increasing mass ratio of Kaol in the mixture, the difference between secondary adsorption and primary adsorption gradually decreases. The affinity of water vapor adsorption on Mt is the biggest, followed by 75:25/Mt:Kaol, 50:50/Mt:Kaol, 25:75/Mt:Kaol, and Kaol, in sequence. Mt has the highest surface potential, and surface potential for Kaol is the lowest. There is a positive relationship between surface potential and the mass ratio of Mt in the mixture. As the pressure increases, Gibbs free energy change quickly enhances and then decreases. The reduction of adsorption spontaneity on Kaol under high pressure is more manifest. Water vapor adsorption spontaneity on clay mixture is improved by enlarging mass ratio of Mt in the mixture. [ABSTRACT FROM AUTHOR]

The surface of calcined kaolinite particles underwent chemical modification using Vinyltriethoxysilane (VTMS) and 3-mercaptopropionic acid (3-MPA). The grafting ratio of VTMS on the calcined kaolinite surface was adjusted by varying its quantity. FT-IR analysis revealed the initial grafting of VTMS onto the kaolinite surface, resulting in the formation of a C=C reactive site on the surface. Subsequently, an olefin click reaction with 3-MPA occurred, leading to the effective grafting of 3-MPA onto the kaolinite surface and the formation of an efficient coating. Thermal analysis indicated that the optimal grafting level was achieved at a modifier content V:K ratio of 0.5. The estimated grafting ratio of the modifier on the kaolinite surface was approximately 40% when V:K was 0.5. Water contact angle and dispersion experiments demonstrated that the surface properties of kaolinite were effectively controlled by this modification approach. At V:K = 0.3, the modified kaolinite particles exhibited good dispersion in both polar and non-polar solvents. In polar solvents, the average particle size of modified kaolinite was below 1100 nm, while in non-polar solvents, it did not exceed 5000 nm. Considering all aspects, a V:K ratio of 0.3 is recommended. Further investigation into the impact of adding 3-MPA on the surface properties of modified kaolinite particles based on V:K = 0.3 revealed that the hydrophilicity of the modified particles could be enhanced. However, it is advised to keep the maximum M:V ratio (3-MPA to kaolinite) at 1.0. [ABSTRACT FROM AUTHOR]

Internal erosion by suffusion within a sand–clay mixture may occur as detachment of clay particles, which is induced by a decrease in ionic concentration (IC) along with application of a high hydraulic gradient. Through designed laboratory soil-column experiments, this study investigates the impact of the IC gradient (stepwise or gradual decrease), clay mineralogy, sand particle size and hydraulic gradient on the suffusion of a sand–clay mixture. The observed breakthrough concentration of clay particles revealed the substantial suffusion of a sand–clay mixture caused by a stepwise decrease in the IC for kaolinite and illite, while similar filtrated quantities of bentonite were observed for stepwise and gradual decreases in IC. In addition, the small-grained sand showed a relatively high susceptibility to suffusion by a stepwise decrease in IC, most likely because of the low reattachment of detached clay particles. The mass of filtrated clay particles evaluated from the area of the observed breakthrough curves in this study provides a clear insight into the need to incorporate the IC gradient when assessing the susceptibility to the suffusion of clay-containing soils. [ABSTRACT FROM AUTHOR]

A powder compact with anion‐uptake ability was prepared prior to the proceeding of the solid‐state reaction involving layered double hydroxide (LDH) and kaolinite during calcination. LDH features anion‐exchangeable capability, and kaolinite is used as a raw potty material because of the sintering property. In the present study, the solid‐state reaction of LDH with kaolinite did not proceed at 750°C, resulting in the formation of a mixture of layered double oxide (LDO) and metakaolinite. Unlike LDO, which typically undergoes anion‐uptake accompanied by LDH reconstruction, metakaolinite does not revert to kaolinite without the use of hydrothermal conditions. In addition, the powder compact composed of LDO crumbled, whereas the one containing a mixture of LDO and metakaolinite remained intact. When the powder compact of LDO and metakaolinite mixture was immersed in a methyl orange (MO) aqueous solution, an LDH–MO intercalation compound was generated within the compact. By contrast, no such compound was generated when LDO powder was immersed in an MO aqueous solution. These results indicated that the successful preparation of a powder compact with distinct anion‐uptake ability was different from powder, owing to that the solid‐state reaction of LDO with metakaolinite did not proceed at 750°C. [ABSTRACT FROM AUTHOR]

Soil improvement via cement-based stabilizers is often necessary to improve the workability and strength of problematic soils. However, understanding the underlying mechanisms of the stabilization process merits further study, particularly concerning changes in the microscale structure that affect macroscale behavior. Mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) are often paired to characterize the microstructure and pore networks and can be used to quantitatively describe pore structure and surface complexity. Fractal geometry (e.g., fractal dimension and lacunarity) has been shown to provide a quantitative description of structural complexity in nature. Therefore, these fractal geometry fundamentals (fractal dimension and lacunarity) were implemented in the analysis of SEM micrographs and MIP results of a single-mineral kaolinitic soil (SA-1 kaolinite) stabilized with a portland cement stabilizer (portland cement Type I/II) to better understand the evolution of the soil microstructure with curing time. Particle size distributions (PSD) were developed based on image analysis of SEM micrographs collected at curing times of 1, 7, 14, 28, and 90 days. The surface fractal dimension obtained via analysis of MIP results was used to describe changes occurring in the pore network with curing time. The formation of cementitious products was inferred from changes in the PSD as gels first formed and then fused with clay surfaces. Box-counting fractal dimensions and lacunarity showed evidence of particle restructuring with cementation. The transition pore size between intraaggregate and interaggregate pores, obtained via fractal analysis of MIP data, decreased with curing time, indicating the formation of hydration products with stabilization. Using fractal geometry to help analyze the microstructural properties of stabilized clays may lead to better insight into their engineering scale behavior. Practical Applications: Problematic soils pose an expensive problem to engineers and are often treated with cement-based stabilizers to improve strength and decrease compressibility or the potential to deform or collapse. However, the underlying mechanism causing problematic behavior, such as low strength or shrinking and swelling, is not well understood and techniques to characterize these soils at the microscopic level are needed to better prevent the damage posed to infrastructure. The current standard of practice utilizes only qualitative measurements of the soil structure and cannot be used in models attempting to predict clay behavior. Therefore, concepts from fractal geometry were used in this study to provide a quantitative, measured value of the soil and pore surface which can be used in future models. Analysis of images at the microscale provided a quantitative measurement of the change in soil structure as stabilization reactions occurred. Moreover, the geometric parameters obtained showed strong correlations with strength values, indicating the utility of the technique for predicting engineering behavior. The results of this study show promise for adapting the box-counting procedure to other, more complex soils. Additionally, because there was a good correlation between the fractal parameters and strength, the results should be correlated with other soil parameters. [ABSTRACT FROM AUTHOR]

This paper presents the results of a selective flocculation/magnetic separation study performed with a sample of iron ore slime from the desliming stage of the industrial flotation circuit of a mine in the southern region in the Quadrilátero Ferrífero-Brazil that was discarded in a tailings dam. Zeta potential measurements of pure minerals previously identified in the sample (goethite = 52.4%, hematite = 26.2%, quartz = 12.3%, kaolinite = 8.2%, and others = 0. 9%) were evaluated to assess the influence of the reagents used (sodium hexametaphosphate – SHMP (dispersant)) and flocculants (corn starch, nonionic polyacrylamide – P2500 and cationic polyacrylamide – P806)) on their surface properties and consequently on the stability of suspensions of the slime and of the pure minerals individually, aiming to establish conditions for selective separation between Fe-bearing minerals (goethite and hematite) and gangue minerals (quartz and kaolinite) in the subsequent magnetic separation step. At pH 10 and a 25 mg/L dosage of SHMP, a higher Fe recovery was verified with starch (2000 g/t) in relation to nonionic and cationic polyacrylamides, and similar Fe contents in all dosages tested of the flocculants. [ABSTRACT FROM AUTHOR]

Globodera pallida, an obligate sedentary endoparasite, is a major economic pest that causes substantial potato yield losses. This research aimed to study the effects of gene silencing of three FMRFamide-like peptides (FLPs) genes to reduce G. pallida infestation on potato plants by using kaolinite nanoclay as a carrier to deliver dsRNAs via drenching. A dsRNA dosage of 2.0 mg/ml silenced flp-32c by 89.5%, flp-32p by 94.6%, and flp-2 by 94.3%. J2s incubated for 5 and 10 h showed no phenotypic changes. However, J2s of G. pallida efficiently uptake dsRNA of all targeted genes after 15 h of incubation. On the other hand, J2s that had been kept for 24 h had a rigid and straight appearance. Under fluorescence microscopy, all dsRNA-treated nematodes showed fluorescein isothiocyanate (FITC) signals in the mouth, nervous system, and digestive system. The untreated population of J2s did not show any FITC signals and was mobile as usual. The drenching of potato cultivar Kufri Jyoti with the dsRNA-kaolinite formulations induced deformation and premature death of J2s, compared with untreated J2s that entered J3 or J4 stages. This study validates that the nanocarrier-delivered RNAi system could be employed effectively to manage G. pallida infestations. [ABSTRACT FROM AUTHOR]

Surfactant injection is a well-established method of chemical EOR processes. Surfactant adsorption into clay layers can prevent their proper performance and thus reduce the oil recovery factor. On the other hand, this adsorption property of clay materials can be used to prevent surface and underground water pollution and reduce soil pollution. In this experimental study, the effect of surfactant concentration, electrolyte type (NaCl and MgCl2), and the solution salinity on fluid adsorption into the interlayer space of different clay types (bentonite and kaolinite) was investigated. XRF analysis was conducted on two relevant clay samples, and immersion and Washburn tests were performed on the desired samples with the Sigma 700 setup. Then, according to the clay type, the most optimal conditions were introduced for the surfactant solution used in the two areas of EOR and environmental processes related to reducing soil pollution. In the EOR processes, the optimal condition for the lowest adsorption amount is C (with 1 CMC concentration and salinity of 100,000 ppm for NaCl salt). This fluid works better in kaolinite formations. In the environmental field related to the reduction of soil pollution, if the pollutants we are looking for are R and S (with alkyl benzene sulfonic acid as the dominant agent), bentonite has a better performance than kaolinite in terms of adsorption and subsequently pollution control. If the polluting fluid contains MgCl2 ions in the exact salinity values, the adsorption amount and soil pollution control will be higher for both adsorbent clays than if our fluid has NaCl salinity. The study's findings have a wide range of applications in surfactant flooding designs, surfactant adsorption optimization, and can be generalized to other detergent types. [ABSTRACT FROM AUTHOR]

To investigate how hydrodynamic cavitation (HC) affects the adsorption of sodium oleate (NaOl) on diaspore and kaolinite surfaces, a comparative study on NaOl adsorption was conducted under different conditions. The flotation and separation of the minerals were also examined with and without HC pretreatment of NaOl. The results show that short-term HC pretreatment of NaOl solutions did not induce a measurable change in the chemical structure of NaOl, but produced micro-nanobubbles (MNBs) and resulted in decreases in the surface tension and viscosity of liquids. When MNBs interacted with minerals, their anchor on solids could affect the contact angles, zeta potentials, and surface NaOl adsorption toward minerals. At low NaOl concentrations, the presence of MNBs reduced the NaOl adsorption capacity and particles' zeta potential while increasing the minerals' contact angle. At higher NaOl concentrations, the presence of MNBs promoted NaOl adsorption, further increased the minerals' contact angle, and further decreases the particles' zeta potential. Additionally, the flotation and separation of minerals can be enhanced at low NaOl concentrations, largely due to the enhanced bubble mineralization through the selective surface-anchoring of MNBs on diaspore. However, the separation efficiency might deteriorate at high NaOl concentrations, though the presence of MNBs amplified the divergences in minerals' surface wettability and zeta potentials. [ABSTRACT FROM AUTHOR]

Flocculation sedimentation state observation could be used to facilitate interaction visualization in laboratories and establish theories for industrial manufacture. Herein, kaolinite was obtained from different sources and labeled as K1 and K2. Those characteristic characterizations indicated that silica sand was difficult to remove from refined commercial kaolinite with different sources. Some biosafe and removable surfactants have been used to evaluate the flocculation sedimentation state of kaolinite-surfactant slurry for a long time, indicating those surfactants could accelerate the settling velocities within a certain range, which could be attributed to sufficient surfactant-kaolinite interactions, but decelerate the settling velocities with the excess surfactant addition, which could be attributed to the surfactant-water colloidal characteristic. Then, the flocculation sedimentation mechanism was illustrated in detail based on the kaolinite-surfactants interaction, indicating that the excellent flocculation sedimentation state was beneficial to silica removal with sedimentation method, but the difficult flocculation sedimentation state was beneficial to size classification with differential centrifugation. [ABSTRACT FROM AUTHOR]

The origin of life is associated with the existing environmental factors of the Precambrian Era of the Earth. The minerals rich in sodium silicates, in aluminum and in other chemical elements, such as kaolinite, were among the factors present at that time. Kaolinite is an abundant mineral on our planet, which indicates that it possibly had an essential role in the origin of the first blocks that constructed life on Earth. Evidence of this is the cherts, which are rocks with a high concentration of silica that retain the vestiges of the most ancient life on our planet. There are also inorganic structures called biomorphs that are like the cherts of the Precambrian, which take on a morphology and crystalline structure depending on the chemical molecules that make up the reaction mixture. To evaluate the interaction of kaolinite with DNA, the objective of this work is to synthesize biomorphs in the presence of kaolinite and genomic DNA that comes from a prokaryote and a eukaryote microorganism. Our results show that the difference between the prokaryote DNA and the eukaryote DNA favors the morphology and the crystalline phase of the calcium silica–carbonate biomorphs, while in the case of the barium silica–carbonate biomorphs, the environmental factors participate directly in the morphology but not in the crystalline phase. Results show that when a mineral such as kaolinite is present in genomic DNA, it is precisely the DNA that controls both the morphology and the crystalline phase as well as the chemical composition of the structure. This fact is relevant as it shows that, independently of the morphology or the of size of the organism, it is the genomic DNA that controls all the chemical elements toward the most stable structure, therefore allowing the perpetuation, conservation and maintenance of life on our planet (since the origin of the genomic DNA in the Precambrian Era to the present day). [ABSTRACT FROM AUTHOR]

Altered minerals introduced by water-rock reactions during geothermal energy recovery may play a role in the frictional properties of fault gouges, perhaps inducing earthquakes. Based on the geological conditions of potential geothermal reservoirs in northeastern Shenzhen, this paper considers the critical pore pressure (about 50 MPa) and critical effective normal stress (about 20 MPa), which may lead to reactivation of the Henggang-Luohu fault zone due to fluid injection into a potential geothermal reservoir at a buried depth of about 2.5 km with the temperature of 150 °C. Under such hydrothermal conditions (50 MPa fluid pressure and 150 °C), thermodynamic calculations suggest that the reaction of Yanshanian granular granite and water, at equilibrium, can produce silica, kaolinite, and chlorite at a mass ratio of 16:7:2. Here we report 19 direct shear experiments performed on simulated fault gouges consisting of the binary mixture of silica + granite, kaolinite + granite, and chlorite + granite, and the multivariate mixture of silica + kaolinite + chlorite + granite, to investigate the effects of altered minerals on frictional properties of simulated granite fault gouges. Velocity stepping experiments were conducted on the wet samples with 10% water content at an initial normal stress of 20 MPa under drained conditions at room temperature. On this basis and together with acoustic emission observation and microstructural analysis, we discussed the likely mechanism responsible for the observed behavior. The results show that, for the presence of a single altered mineral, silica has little effect on the friction coefficient, though it contributes to velocity weakening and even stick-slip events. Whereas, clay minerals can significantly decrease the friction coefficient, though they have a contribution to velocity strengthening. For the presence of a mixture of silica + kaolinite + chlorite, clay minerals play a dominant role in controlling frictional properties of the simulated fault gouges: altered minerals can also significantly decrease the friction coefficient and contribute to velocity strengthening. Development of R1 shear planes was observed using microstructural analysis for the simulated granite fault gouges consisting of 0% or 33% of the altered minerals, while the R1 shear plane cannot be observed anymore in the sample consisting of 67% of the altered minerals. The number of acoustic emission events decreases significantly when the content of the altered minerals is 33%~67%. This may indicate a transition in the deformation mechanism from brittle to semi-plastic. Our study suggests that if geothermal energy recovery is carried out in northeastern Shenzhen, the fluid injection pressure should be controlled to avoid the slip of the fault. [ABSTRACT FROM AUTHOR]

Coal is a mixture of organic macerals and minerals. The presence of minerals can lead to differences in the macromolecular structure of coal, resulting in significant heterogeneity in its mechanical properties, which in turn affects the overall coalbed methane production, fracturing and transformation effects, and the large-scale application of mature technologies within the block. Taking typical anthracite and kaolinite minerals from the Qinshui Basin as the research object, the influence of kaolinite and its content on the mechanical properties of anthracite is quantitatively studied through molecular dynamics methods. The molecular structure and pore characteristics of anthracite under different mineral contents are analyzed, and its microscopic mechanism is revealed from the perspective of energy and ordering. The results indicate that: ① There are both van der Waals forces and hydrogen bonding forces during the binding process between coal organic matter and kaolinite, and the intensity of hydrogen bonding is higher than that of van der Waals forces. The probability, interaction strength, and orderliness of kaolinite molecules appearing around coal organic matter increase with the increase of mineral content. ② The porosity of anthracite decreases linearly with the increase of kaolinite content, with φ=−0.229 3a+9.629 5, while the bulk modulus, elastic modulus, and shear modulus of anthracite all increase linearly with the increase of kaolinite content. The Poisson’s ratio decreases exponentially with the increase of kaolinite content. ③ The degree of mechanical heterogeneity of anthracite increases overall with the increase of kaolinite content. The variability of bulk modulus, elastic modulus, and shear modulus under different kaolinite contents can be divided into five parts: very low, low, medium, high, and very high. The coefficient of variation of Poisson's ratio is all less than 0.1, indicating very low variability. ④ As the content of kaolinite increases, the interaction energy between coal organic matter and kaolinite shows a linear increase (Einteraction=4.558 5a+443.929). Compared with pure organic matter, when the content of kaolinite reaches 20%, the bond energy and van der Waals energy of anthracite increase by 63.86% and 48.06%, respectively. ⑤ The internal reason why kaolinite enhances the mechanical properties of coal is that it occupies a certain pore space after entering the coal organic matter and interacts with the aromatic carbon skeleton and different functional groups of the coal organic matter. The higher the content of kaolinite, the greater the degree of filling the pores of the coal macromolecular structure and the energy of the coal macromolecular structure, resulting in a decrease in the porosity of the coal macromolecular structure, an increase in orderliness, and an increase in mechanical strength and resistance to deformation.

To investigate how hydrodynamic cavitation (HC) affects the adsorption of sodium oleate (NaOl) on diaspore and kaolinite surfaces, a comparative study on NaOl adsorption was conducted under different conditions. The flotation and separation of the minerals were also examined with and without HC pretreatment of NaOl. The results show that short-term HC pretreatment of NaOl solutions did not induce a measurable change in the chemical structure of NaOl, but produced micro-nanobubbles (MNBs) and resulted in decreases in the surface tension and viscosity of liquids. When MNBs interacted with minerals, their anchor on solids could affect the contact angles, zeta potentials, and surface NaOl adsorption toward minerals. At low NaOl concentrations, the presence of MNBs reduced the NaOl adsorption capacity and particles’ zeta potential while increasing the minerals’ contact angle. At higher NaOl concentrations, the presence of MNBs promoted NaOl adsorption, further increased the minerals’ contact angle, and further decreases the particles’ zeta potential. Additionally, the flotation and separation of minerals can be enhanced at low NaOl concentrations, largely due to the enhanced bubble mineralization through the selective surface-anchoring of MNBs on diaspore. However, the separation efficiency might deteriorate at high NaOl concentrations, though the presence of MNBs amplified the divergences in minerals’ surface wettability and zeta potentials.

Surfactant injection is a well-established method of chemical EOR processes. Surfactant adsorption into clay layers can prevent their proper performance and thus reduce the oil recovery factor. On the other hand, this adsorption property of clay materials can be used to prevent surface and underground water pollution and reduce soil pollution. In this experimental study, the effect of surfactant concentration, electrolyte type (NaCl and MgCl2), and the solution salinity on fluid adsorption into the interlayer space of different clay types (bentonite and kaolinite) was investigated. XRF analysis was conducted on two relevant clay samples, and immersion and Washburn tests were performed on the desired samples with the Sigma 700 setup. Then, according to the clay type, the most optimal conditions were introduced for the surfactant solution used in the two areas of EOR and environmental processes related to reducing soil pollution. In the EOR processes, the optimal condition for the lowest adsorption amount is C (with 1 CMC concentration and salinity of 100,000 ppm for NaCl salt). This fluid works better in kaolinite formations. In the environmental field related to the reduction of soil pollution, if the pollutants we are looking for are R and S (with alkyl benzene sulfonic acid as the dominant agent), bentonite has a better performance than kaolinite in terms of adsorption and subsequently pollution control. If the polluting fluid contains MgCl2 ions in the exact salinity values, the adsorption amount and soil pollution control will be higher for both adsorbent clays than if our fluid has NaCl salinity. The study's findings have a wide range of applications in surfactant flooding designs, surfactant adsorption optimization, and can be generalized to other detergent types.

• Rice straw-derived dissolved organic matter (DOM) included four main components. • The presence of goethite significantly promotes the straw decomposition process. • OM's adsorption capacity for Cd increased with the straw decomposition time. • The presence of minerals promoted the OM's adsorption capacity and affinity of Cd. • Surface precipitation and complexation dominant Cd adsorption by OM. Organic matter (OM) derived from the decomposition of crop residues plays a key role as a sorbent for cadmium (Cd) immobilization. Few studies have explored the straw decomposition processes with the presence of minerals, and the effect of newly generated organo-mineral complexes on heavy metal adsorption. In this study, we investigated the variations in structure and composition during the rice straw decomposition with or without minerals (goethite and kaolinite), as well as the adsorption behavior and mechanisms by which straw decomposition affects Cd immobilization. The degree of humification of extracted straw organic matter was assessed using excitation-emission matrix (EEM) fluorescence and Ultraviolet-visible spectroscopy (UV-vis), while employing FTIR spectroscopy and XPS to characterize the adsorption mechanisms. The spectra analysis revealed the enrichment of highly aromatic and hydrophobic components, indicating that the degree of straw decomposition and humification were further intensified during incubation. Additionally, the existence of goethite (SG) accelerated the humification of OM. Sorption experiments revealed that the straw humification increased Cd adsorption capacity. Notably, SG exhibited significantly higher adsorption performance compared to the organic matter without minerals (RS) and the existence of kaolinite (SK). Further analysis using FT-IR spectroscopy and XPS verified that the primary mechanisms involved in Cd immobilization were complexion with —OH and —COOH, as well as the formation of Cd-π binds with aromatic C=C on the surface of solid OMs. These findings will facilitate understanding the interactions of the rice straw decomposing with soil minerals and its remediation effect on Cd-contaminated farmland. [Display omitted] [ABSTRACT FROM AUTHOR]

A new approach is proposed to assess the degree of defect density of kaolinite minerals using their IR spectra in the OH-stretching vibration region. Three linear equations were obtained that relate the ratios of spectroscopic parameters to each other: + 1.247; + 2.8696; , where: FWHM(νi) is a full width at half maximum and A(νi) is the integral intensity of Lorentzian absorption bands at ν1 ~ 3697 cm–1, ν2 ~ 3670 cm–1, ν3 ~ 3652 cm–1 and ν4 ~ 3620 cm–1, respectively. These equations made it possible to establish criteria for decomposing the IR spectra into individual bands (νi) and determining the optimal values for the FWHM(νi) and A(νi) parameters used for calculating the contents of high-ordered kaolinite (HOK) and low-ordered kaolinite (LOK) phases in natural samples with an accuracy of ~5%. [ABSTRACT FROM AUTHOR]