Dioctahedral micas are composed of two tetrahedral sheets and one octahedral sheet to form TOT or 2:1 layers. These minerals are widespread and occur with structures differing by (1) the layer stacking mode (polytypes), (2) the location of vacancies among non-equivalent octahedral sites (polymorphs), and (3) the charge-compensating interlayer cation and isomorphic substitutions. The purpose of the

Highly weathered soils of the humid tropics generally provide a poor mineral reserve of potassium (K), but evidence has been found which indicates that even in such soils non-exchangeable forms of K can be made plant available and this warrants further investigation. The objective of this study was, therefore, to determine the extent to which K can be released from poorly available reserves over a

Enzymes adsorbed on clay minerals and soil colloids may exhibit lower activities compared to those of free enzymes. A particular toxic metal may affect the activity of the adsorbed enzyme less critically than that of the free form, however. This information is necessary for predicting catalytic performances of clay-immobilized enzymes in natural soils as well as in food, pharmaceutical, and chemical

Fire resistance performance is one of the most important requirements in geological storage conditions in order to improve the resistance of storage packages to high thermal constraints (in the case of a fire for example). With the need to develop new fire-resistant materials, the aim of the present study was to develop fire-resistant geopolymer binders based on Callovo-Oxfordian (COx) argillite. Two

Despite the numerous studies on geomaterials in Tunisia, quite a few clay varieties are not yet well defined. In fact no detailed geological, mineralogical, or geochemical characterizations of Tunisian palygorskite deposits have been carried out to date. The purpose of the present work was to study the continental Eocene clay deposit at the southern end of the Tunisian North axis, between Jebel Rheouis

Purification of raw bentonites and organo-bentonite preparations is sometimes required for industrial use. Zeta (electrokinetic) potential (ζ), contact angle (wettability/hydrophobicity), and surface free energy (SFE) are important surface characteristics and vary significantly according to the applied surfactant concentration when preparing organo-bentonite. Changes in these characteristics determine

Most investigations into clay-mineral stability and new mineral formation within engineered barrier system (EBS) materials for geologic repositories of nuclear waste have focused on temperatures <100°C. In response to the United States Department of Energy’s interest in disposing of waste packages with higher thermal loads, higher temperature (200–300°C) and pressure (~150 bar), long-term (6-week to

Infrared analyses of clay mineral samples are usually performed by transmission techniques. While transmission measurements are easy and inexpensive, the sample preparation plays a critical role in the quality of the data. Alternatively, attenuated total reflection (ATR) provides a powerful and often simpler analysis method. However, the ATR spectra reveal significant differences when compared to transmission

Structure control and quantitative evaluation of porous materials are essential for many industrial and consumer applications of clay minerals, and nanotubular halloysite (HNT) has been used extensively for such purposes; performance enhancements are still needed, however. The objective of the present study was to improve the gas-adsorption capacity of HNT by controlling the particle size and porosity

Swell-shrink clays are widely distributed in the Guangxi province of southern China in the form of expansive soils and lateritic clays. They have high particle dispersion, poor permeability, and significant swell-shrink properties. In recent decades, a series of problems closely related to the physical-mechanical properties of the swell-shrink clays have been encountered in various engineering projects

Understanding clay-mineral assemblages forming in saline lakes aids in reconstructing paleoenvironments on Earth and other terrestrial planets; this is because authigenic phyllosilicates are sensitive to the prevailing geochemical conditions present during formation. In most geochemical models, evaporative concentration favors sepiolite with increasing silica and Mg2+ concentrations without considering

Results from earlier laboratory and field experiments were interrogated for the possibilities of sequestration, or long-term accumulation, of carbon from excess greenhouse gases in the atmosphere. In the laboratory study, samples of three (top) soils dominated by kaolinite and illite (together), smectite, and allophane were examined for the adsorption and desorption of dissolved organic carbon (DOC)

In the production of alumina (Al2O3) from clays by acid leaching, thermal activation by calcination is applied widely as a pre-treatment to improve the dissolution of aluminum. Previous studies have focused only on the thermal behavior of high-purity kaolinite and pyrophyllite, individually. However, thermal activation of complex clay ores containing several silicate minerals and their effect on aluminum

The problem to be solved is whether Al is a necessary component of Fe-Mg chlorites. Very unusual Al-depleted and Fe-enriched trioctahedral chlorites with the empirical formulae Na0.05Ca0.05(Fe2+3.01Mg2.01Ti0.14Fe3+0.04)Σ6.00[(Si3.53Fe3+0.41Al0.06)Σ4.00O10](OH)8·nH2O (Sample 1) and Na0.05Ca0.01(Fe2+3.26Mg1.97Fe3+0.75Mn0.01Ti0.01)Σ6.00[(Si3.16Fe3+0.75Al0.09)Σ4.00O10](OH)8 (Sample 2) have been discovered

This article was updated to fix formatting errors in Eqs. 1, 2 and 3 introduced in the production process.

Molecular dynamics (MD) simulations provide an accurate description of the mineral–fluid interface from the perspective of the atomistic level taking into account all atom interactions. This simulation approach is computationally expensive if applied to large molecular systems. Classical Fluid Density Functional Theory (f-DFT) delivers structural and thermodynamic information at comparatively small

The adsorptive behavior of clinoptilolite (Cpt) zeolite in its raw and nickel-exchanged form towards m-xylene/p-xylene/ethylbenzene unary, binary, and ternary mixtures was investigated. The motivation behind the research was to elucidate whether Cpt in its raw or ion-exchanged form could exhibit distinctive selective adsorption behavior. The natural Cpt (Si/Al atomic ratio = 4.59) was ion-exchanged

The purification of clay minerals prior to their use as catalysts can escalate processing costs so methods are needed whereby less purification is necessary. One such potential method is acid treatment of the unpurified clay minerals. The main objectives of the present study were to develop the optimal acid-treatment conditions and to determine how the acidic properties of the modified clay samples

The chemical composition of the source magma along with the physiochemical conditions of the depositional environment are the main controlling factors in determining the behavior and mobility of trace elements and rare earth elements (REEs) during the transformation of volcanic ash to bentonite. The purpose of the present study was to determine the distribution pattern and mobility of trace elements

The efficient separation of hexane isomers from the light naphtha fraction is a significant challenge in the petrochemical industry. 5A zeolite adsorbent is used commercially to sieve alkane isomers. In this study, 5A zeolites were synthesized using a low-cost natural clay mineral precursor, i.e. palygorskite (PAL), with the addition of crystallization directing agent (CDA). By varying the mass ratio

The rheological properties of sepiolite gels in relation to solution chemistry, fiber charge, and microstructure are poorly understood. The purpose of this study was to bring more clarity to this topic by quantifying the effects of solution pH, ionic strength, and adsorbed tetrasodium pyrophosphate (TSPP) additive on rheological properties. The electrical charge on sepiolite fibers was investigated

Quantification of mineral assemblages in near-surface Earth materials is a challenge because of the often abundant and highly variable crystalline and chemical nature of discrete clay minerals. Further adding to this challenge is the occurrence of mixed-layer clay minerals, which is complicated because of the numerous possible combinations of clay layer types, as defined by their relative proportions

The presence of pharmaceutical pollutants in the environment is one of the most pressing environmental problems. Adsorption from solution is an effective way to remove pharmaceuticals from liquid media, but the problem then is to separate the adsorbent from the liquids. The objective of the present study was to remove nitrofurazone from aqueous solutions using a bentonite/magnetite composite, prepared

A review of the models proffered to advance the notion of the metastability of illite shows that these models are not supported by the various data groups that have become available. Given that clay minerals are products of water–rock interactions, low-temperature hydrothermal experiments provide singular insights into their relative stabilities; such experiments with natural materials of contrasting

In the soils of western Jilin Province in northeastern China, some significant gaps have been observed between the fraction of the soil existing as clay-size particles (<0.002 mm) and the amount attributable to crystalline clay minerals, and that the relative proportions of crystalline clay minerals to the total clay-size fraction (CP) apparently varies with latitude. The purpose of the present study

To identify the mechanisms for and to estimate the photochemical reaction efficiency of molecules in solid-state host materials is difficult. The objective of the present research was to measure the photogeneration efficiency of the methylviologen cation radical (MV+•) hosted in a semi-transparent hybrid film composed of MV2+ and saponite, a 2:1 clay mineral. MV+• is the one-electron reduced species

Intercalation of large organocations into 2:1 clay minerals may be hampered by two problems: on one hand, the solubility of organocations in water is limited and the resulting high selectivity for adsorption in the polar solvent may lead to non-equilibrium structures. On the other hand, the large expansion of the interlayer space will slow down kinetics of ion exchange considerably. The best workaround

When present at elevated levels in drinking water, arsenic is toxic, and magnesian clays are gaining recognition as a source of elevated arsenic in groundwater. In the crust and upper mantle of Earth, arsenic incorporation into clay minerals is influenced by geochemical conditions associated with hydrothermal fluids and metamorphic processes (e.g. serpentinization), meaning that As is a useful tracer

The construction of organic-inorganic hybrid ferroelectric materials with larger, high-polarity guest molecules intercalated in kaolinite (K) faces difficulties in terms of synthesis and uncertainty of structure-property relationships. The purpose of the present study was to optimize the synthesis method and to determine the mechanism of ferroelectric behavior of kaolinite intercalated with p-aminobenzamide

This article was updated to correct errors in the MATLAB code introduced during the production process.

This article was updated to correct changes to the text made during production. The phrase “Fe can be placed in one of three ways at j = 1 and 2” was updated.

Six-membered ring heterocyclic compounds are widely present in the Earth's surface environments as biological organic molecules composed of soil organic matter including plant and microbial residues, while little is known about their effect on the dissolution of silicate minerals including amorphous silica. To evaluate the effect of these biological molecules on amorphous silica dissolution, dissolution

Abstract The aim of the present study was to examine effects of black liquor-montmorillonite (BL-Mnt) complexes on the mechanical and thermal properties of epichlorohydrin rubber. Considering the stability effect of lignin and the barrier property of clay minerals, a significant enhancement of thermo-oxidative aging properties of ECO/BL-Mnt composites was expected. Poly (epichlorohydrin-co-ethylene

Abstract Chitosan (CTS) modified montmorillonite (Mnt) composites (CTS-Mnt), which have been widely reported for the adsorption of heavy-metal ions and biological dyes, have not been applied to the field of mycotoxin adsorption. The current study was focused on the preparation of CTS-Mnt by calcination as a mycotoxin adsorbent for the efficient removal of aflatoxin B1 (AFB1). The CTS-Mnt samples obtained

Abstract Waste brownfield-site soils contaminated with heavy metals such as Zn and Cr are of critical environmental concern because of the rapid urbanization and industrialization that is occurring in China. Thermal treatment can fix heavy metals in specific mineral structures, which might be a promising technology for remediation and reutilization of the metal-contaminated soils. The objective of

Abstract Diffraction effects from interstratified phyllosilicates have been studied extensively, and several computer programs such as NEWMOD© are available to facilitate interpretation of X-ray diffraction (XRD) profiles. However, accurate quantification of samples containing multiple interstratified phyllosilicate minerals is difficult due to the generally subjective nature of interpretations. More

Although multiple types of adsorption sites have long been observed in montmorillonite, a consistent explanation about the chemical structure of these adsorption sites has not yet been established. Identifying the cation interlayer adsorption sites based on the octahedral cation distribution on montmorillonite was investigated in this study by using a Density Functional Theory (DFT) simulation. A clay

Abstract This work presents Atomistic Topology Operations in MATLAB (atom), an open source library of modular MATLAB routines which comprise a general and flexible framework for manipulation of atomistic systems. The purpose of the atom library is simply to facilitate common operations performed for construction, manipulation, or structural analysis. Due to the data structure used, atoms and molecules

The growing use of nano titanium dioxide (TiO2) in consumer and agricultural products has accelerated its introduction into terrestrial environments, where its impact has not been documented extensively. TiO2 toxicity arises primarily from its ability to photochemically generate reactive oxygen species (ROS), including hydrogen peroxide (H2O2). While common ligands in soil porewaters can either hinder

Vermiculite is a mineral with many potential uses in various industrial areas, such as in insulation, horticulture, and environmental applications. The regolith of the Sokli carbonatite intrusion in northern Finland consists of weathered micas which reportedly contain vermiculite. The aim of the present study was to characterize the weathered mica in order to determine if the weathered regolith contains

Lubricants are an essential component in high-performance mechanical equipment, but traditional lubricants are becoming inadequate for meeting the increasing demands for anti-friction and anti-wear properties and they discharge harmful chemicals to the environment. The purpose of the present study was to explore the use of sepiolite as a novel oil additive to extend the performance of lubricants. Sepiolite

The widespread Balıkesir bentonite deposits within the Miocene volcano-sedimentary units in western Anatolia have economic potential; they are important raw materials for the paper and bleaching industries in Turkey. No detailed geological, mineralogical, geochemical, or genesis characterizations of these bentonite deposits have been carried out to date. The present study was undertaken to close this

Photo-assisted selective catalytic reduction (photo-SCR) has been considered as a promising strategy for NOx removal in recent decades. The purpose of the present work was to test the effectiveness of La1–xPrxCoO3, supported on the surface of natural palygorskite (Pal) by a facile sol-gel method, as a photo-SCR for the removal of NOx from wastewaters. The structure, acidity, and the redox property

Photocatalytic degradation of polluted water by means of minerals, such as clays and oxides, which have surfaces that exhibit catalytic properties, has been suggested to be a useful new strategy to promote both organic and inorganic pollutant degradation. Nevertheless, much still remains to be studied about the capability of mixed metal oxides derived from lanthanum-containing layered double hydroxides

To apply hydrotalcites more effectively to the problem of dye wastewater, the effects of divalent metal ions on the structure and stability of hydrotalcites, especially on their photocatalytic activity, were compared. In the present study, M/Cr hydrotalcites (M3Cr-CO3-LDHs) (in which M = Mg, Co, Ni, Cu, Zn), where the M/Cr molar ratio was 3, were prepared by the co-precipitation method. The structures

Adsorption of uranyl (UO22+) ions to mineral surfaces is a potentially effective method for removing this hazardous metal from water, but other toxic trace metal ions (Xn+: Rb+, Sr2+, Cr3+, Mn2+, Ni2+, Zn2+, Cd2+) in uraniferous wastewaters compete with UO22+ for adsorption sites and thus may diminish the capacity of adsorbents to sequester UO22+. A better understanding of competitive adsorption among

Hydrophobicity, high viscosity, and dispersion are important properties for organo-montmorillonites, and all organo-montmorillonite configurations have yet to be fully characterized with respect to this property. High-viscosity montmorillonite (Mnt) is useful in gels and as an adsorber. The current study focused on modifying Mnt using organic cations and anions of various chain lengths in batch experiments

The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties

The electron spin resonance (ESR) spectra and the natural and gamma-induced thermoluminescence (TL) glow curves of a series of variably cation-exchanged Fe-Ca-clays prepared from SWy-1 montmorillonite were examined. The ESR signal (g = 2) intensity associated with the surface Fe was found to increase linearly with surface Fe content up to a nominal concentration of 50% exchangeable Fe. At > 50% exchangeable

Dehydration-induced luminescence (DIL), the emission of light from a clay paste upon dehydration, was characterized experimentally for a colloidal kaolinite. The relationship between total photon count of the emitted light and film thickness is linear up to a thickness of 30 micrometers. The photon emission was obtained over a critical range of water contents (25-60%) of the oven-dry clay, and the

Adsorption isotherms and UV-visible and Mossbauer spectroscopic data point to specific interactions between flavomononucleotide (FMN) and Fe(3+)-smectite. The maximum amount of FMN adsorption was 0.3 mmole/g of Fe(3+)-smectite giving a 1:1 molar proportion of Fe3+ and FMN. The results suggest a Fe(3+)-FMN complex residing at the smectite surface. Other homoionic smectites (Cu2+, Zn2+, and Ca2+) exhibited

Several new, room-temperature luminescent phenomena, resulting from the interaction of kaolin and various amino compounds, have been observed. The emission of light from kaolin pastes (treated with quinoline, pyridine, hydrazine, monoethanolamine, n-butylamine, and piperidine) was shown to decay monotonically over a period of hours to days. More light was released by a given amino compound after it

Microporous structure in zeolite leads to diffusion limitation, which causes coke formation and is harmful to catalytic reactions. Hierarchical zeolite containing primary microporosity and secondary porosity at the meso- and macroscales has received much attention due to its enhanced mass transport. Hierarchical Y zeolites were obtained by treating NH4-Y zeolite with high-temperature calcining and

Adsorption desulfurization is a potential new method for deep desulfurization of fuel oil. The development of adsorbents with high adsorption capacity and selectivity is the core of deep adsorption desulfurization. The adsorption behavior of thiophene in MCM-41 mesoporous materials modified by various metal ions was studied in order to understand the adsorption desulfurization process of molecular

The adsorption of bovine serum albumin (BSA) protein is important for protein research but remains a great challenge. Here, the hydrothermal method and calcination in a hydrogen-argon mixed atmosphere were used to obtain ordered mono-crystalline magnetic Fe3O4 nanorings with controllable size and uniform structure, which were applied to the adsorption of BSA protein. The results showed that the magnetic

Large kaolin deposits developed by weathering on Precambrian granitic rocks have been discovered in the Caluquembe area, Huíla province, Angola. To determine accuracy of analysis and to evaluate the kaolinite grade, a full-profile Rietveld refinement by X-ray Powder Diffraction (XRPD) and Thermal Gravimetric Analysis (TGA) was used. Caluquembe kaolin is composed mainly of kaolinite (44–93 wt.%), quartz

Although fluorescence detection is a sensitive method in the field of pollutant analysis, its application is restricted due to the fluorescence shown by organic material being quenched after aggregation and to low photo-thermal stability. To address these issues, a novel mineral/dye composite material was prepared by intercalating a fluorescence molecule, Rhodamine (R6G), into the interlayer space

In order to provide a theoretical foundation for the utilization of tailings as supplementary cementitious materials, the pozzolanic activity of muscovite—a typical mineral phase in tailings—before and after mechanical activation was investigated. In this study, significant pozzolanic activity of muscovite was obtained as a result of the structural and morphological changes that were induced by mechanical

The increasing demands for oil and gas and associated difficult drilling operations require oil-based drilling fluids that possess excellent rheological properties and thermal stability. The objective of the present work was to investigate the rheological properties and thermal stability of organo-montmorillonite (OMnt) modified with various surfactants and under various loading levels in oil-based

Np and Pu are two important actinides of concern for the safe long-term disposal of nuclear waste. Both actinides are, in addition, constituents of global nuclear fallout. Investigation of their environmental behavior requires ultra-sensitive analytical methods, but current methods for a concurrent determination in clay minerals are lacking. In the present study, a Pu isotope was investigated for use