Gray-black kaolinitic claystones of industrial value are abundant in Upper Carboniferous–Lower Permian coal-bearing strata of the Datong Coalfield of northern China. The main types are tonsteins and cryptocrystalline kaolinitic claystones, distinguished by the thinness and greater crystallinity of kaolinite in the former and by the presence of detrital illite and authigenic pyrite in the latter. In

Halloysite nanotubes (HNTs) have attracted much attention as delivery carriers for various drugs, but the loading of one such drug, quercetin, on HNTs has been investigated only rarely and usually involved cyclic vacuum pumping. The main objective of the present study was to develop a novel carrier system based on HNTs for quercetin delivery without a vacuum process and to investigate the effect of

Bentonite is used as a catalyst in the removal of olefins from aromatic compounds and the present study was designed to investigate how its performance might be improved by various treatments. Bentonite from Semnan mine, Iran, was used in the study following initial characterization. In order to investigate the effect of acid and thermal treatments on the removal of olefins from aromatic compounds

X-ray powder diffraction (XRPD) is found consistently to be the most accurate analytical technique for quantitative analysis of clay-bearing mixtures based on results from round-robin competitions such as the Reynolds Cup (RC). A range of computationally intensive approaches can be used to quantify phase concentrations from XRPD data, of which the ‘full-pattern summation of prior measured standards’

Hydrothermal alteration led to development of the Yarıkçı clay deposit within the Mesozoic chlorite-, muscovite-, chlorite-muscovite-schist, and garnet-graphite phyllite units along NW–SE- and N–S-trending faults in Mihalıççık in western central Anatolia. The geological, mineralogical, and geochemical characteristics and genesis of this economically important clay deposit have not been examined in

Knowledge of clay mineralogy is essential for understanding the source areas and weathering environments of fluvial sediments, particularly in large reservoirs facing serious problems with sediment deposition, such as the Three Gorges Reservoir (TGR) in east-central China. The purpose of the present study was to identify the sediment provenances and weathering regimes contributing to the sediment load

Palygorskite-rich mudstone interbedded with gypsum occurs in the Neogene Baiyanghe Formation in the Yangtaiwatan basin, northwest China, but the genesis of palygorskite in the mudstone is unclear. The objective of the present study was to clarify the manner by which the palygorskite evolved by analyzing the mineralogical and geochemical characteristics of the mudstone. The mineralogical composition

In the absence of the necessary valley topography, karst depressions are sometimes used to construct conventional impoundments in order to contain tailings. Leakage is a primary concern for such impoundments. The purpose of the current study was to determine the characteristics and barrier performance of laterite mantling karst depressions, using, as an example, the Wujiwatang (WJWT) tailings impoundment

Injured bone tissues can be healed with bone grafts, but this procedure may cause intense pain to the patient. A slow and localized delivery of nonsteroidal anti-inflammatory drugs (NSAIDs) could help to reduce the pain without affecting bone regeneration. The objective of the present study was to use [Mg-Al]-layered double hydroxide (LDH) as a matrix for controlled release of sodium naproxen (NAP)

The stability, dispersion, and rheological properties of clay suspensions are important in the process of drilling. Organic clays were obtained traditionally by cation exchange, which is thermally unstable due to weak electrostatic interaction between the cationic surfactant and clay minerals. The purpose of the present study was to yield a stable and well dispersed organic bentonite (OBent) as a rheological

The present study provides an example of the accurate identification of polytypes of trioctahedral 1:1 layered silicates from single-crystal X-ray diffraction data collected with the aid of a four-circle diffractometer equipped with an area detector. Single crystals of the mineral cronstedtite from the Nagybörzsöny gold ore deposit, northern Hungary, were studied. The chemical composition of some crystals

Titanium dioxide (TiO2, rutile) nanoparticles, inorganic ultraviolet absorbers, are used extensively in sunscreen cosmetics as an inorganic ultraviolet (UV) absorber to prevent skin damage; because of their nanotoxicity, use in combination with a support, such as montmorillonite (Mnt), rather than alone, is suggested. Mnt-supported TiO2 composites (Mnt-TiO2) for sunscreens are most suitable when the

The dispersive behavior dynamics of clay determine soil characteristics such as permeability and aggregate stability, and, consequently, crop productivity. Soil dispersion is heavily influenced by the ionicity of clay–cation bonds and has been shown to be related to the net negative charge and pH of the system. Little work has been done, however, which considers these factors together, especially for

Loess is a collapsible soil; when it collapses, it can cause significant damage to structures built on it. Improvement in the stability and strength performance of loess is necessary to meet engineering needs. In the present study, the effects on the physical-chemical and rheological characteristics of Ghardaïa loess of adding bentonite and lime (southern Algeria) were examined. Rheological characterization

Geopolymers have the potential to function as an environmentally friendly substitute for ordinary Portland cement, with up to 80% less CO2 emission during production. The effect is best utilized for geopolymers prepared with amorphous silica instead of waterglass (Na2xSiyO2y+x) to adjust the Si:Al ratio. The reactivity of the precursors with the alkaline activator affects the final mineralogical properties

Several procedures for hydrothermal synthesis of saponite can be found in the literature. They differ in terms of the preparation conditions of the precursor and of the synthesis temperature. The objective of the present study was to investigate how these two parameters influence the structure of the final synthesis product. The precursor was prepared from Mg(NO3)2, Al(NO3)3, and Na4SiO4 in three different

The harm caused by mine tailings has become increasingly problematic in recent years, so efforts are needed to dispose of or reutilize them in environmentally friendly ways. The objective of the present study was to find out if the hydration properties of muscovite contained in mine tailings are suitable for it to be used as a pozzolan in cement, after undergoing mechanical activation. Aqueous suspensions

Because they are so widespread, the use of saponites is significant in many industries. The modification of saponite-rich clay minerals is known to improve their existing characteristics and may provide new functional properties. The objective of the present paper was to characterize the effects of adding nanosized graphene-like molybdenum (Mo) and tungsten (W) sulfides on the textural and surface

Conventional superplasticizers based on polycarboxylate ether (PCE) show an intolerance to clay minerals due to intercalation of their polyethylene glycol (PEG) side chains into the interlayers of the clay mineral. An intolerance to very basic media is also known. This makes PCE an unsuitable choice as a superplasticizer for geopolymers. Bio-based superplasticizers derived from starch showed comparable

Ion-exchange modeling is one of the most widely used methods to predict ion adsorption data on clay minerals. The model parameters (e.g. number of adsorption sites and the cation adsorption capacity of each site) are optimized normally by curve fitting experimental data, which does not definitively identify the local environment of the adsorption sites. A new approach for constructing an ion-exchange

A lustrous appearance and interference-based colors make pearlescent pigments attractive for use in applications such as automotive paints, plastics, consumer electronics, and cosmetics. A combination of interference and absorption in the visible light spectrum improves significantly the hiding power as well as the color strength of pearlescent pigments while potentially extending their color range

Alkaline solutions have significant effects on the mineral composition and on the microstructure of bentonite; in relevant geoenvironmental engineering applications, therefore, the properties of bentonite buffer materials must be taken into consideration in the presence of alkaline solutions. The objective of the present study was to determine the effect of alkaline conditions on the swelling of bentonite

The conversion of CO2 into carbon feedstock via CO2 hydrogenation to methane requires a stable catalyst for reaction at high temperatures. Zeolite NaY (abbreviated hereafter as NaY) synthesized from naturally occurring kaolin provides a stable support for Ni nanoparticles. Kaolin can be further dealuminated using sulfuric acid to reduce the Si/Al ratio, but the presence of the remaining sulfur is detrimental

Çayırbağı magnesite is one of numerous magnesite deposits occurring throughout Turkey. In this deposit, sepiolite and newly found stevensite occur locally as two daughter minerals formed from magnesite. The sepiolite and stevensite show distinctive compositions and modes of formation compared to those described in the literature. The objective of the current study was to characterize these minerals

The formation conditions and stability fields of Fe-serpentines are still poorly understood in both terrestrial (natural or anthropic) and extraterrestrial environments. Knowledge of the effects of physical-chemical parameters on compositional and structural features of Fe-serpentines is lacking, and only a few thermodynamic parameters of these minerals are available in the literature. To fill these

Soil–alkali interaction leads to abnormal soil behavior due to significant changes in mineralogy and morphology. The effect of alkali on the swelling behavior of natural clays has been explored in recent years, but the swelling behavior of alkali-transformed clay minerals is still unclear. The objective of the current study was to investigate the effect of alkali concentration on swelling characteristics

K-Ar isotopic dating has been applied to alkali-rich nanometer-sized illite separates of bentonites since the late 1990s. In the present study, K-Ar and Rb-Sr isotopic analyses were based on mineralogical determinations and morphological observations of similarly nm-sized separates (<0.02, 0.02–0.05, and 0.05–0.1 μm) depleted in alkalis and recovered from Santonian (85.8–83.5 Ma) bentonites of the

Bisphenol A (BPA), an endocrine disrupting compound, is of concern because of its wide presence throughout the environment and its harmful effects. The present study aimed to prepare an eco-friendly, low-cost, and efficient adsorbent for removal of BPA from wastewater. A natural Tunisian clay was used as a raw material. First, the clay was purified and then modified with hexadecyltrimethylammonium

The present study considered the problem of halloysite nanoscroll synthesis by energy modeling of the formation of chrysotile and halloysite particles. The main aim of the study was to reveal an energy preference between scrolled and platy morphologies of the particles. Both hydrosilicates possess the ability to scroll spontaneously but relatively facile hydrothermal synthesis of the nanoscrolls is

The removal of pesticide contaminants from water is a key priority in environmental remediation, and requires intensive effort; this necessitates modification of the properties of pillared clays (PILCs) such as porosity, pore-volume, surface area, and synthesis methods. The purpose of the present study was to test the ability of Al-pillared bentonite (Al-PILB), using [Al13O4(OH)24(H2O)12]7+ and [A

Kaolins and clays are important raw materials for production of supplementary cementitious materials and geopolymer precursors through thermal activation by calcination beyond dehydroxylation (DHX). Both types of clay contain different polytypes and disordered structures of kaolinite but little is known about the impact of the layer stacking of dioctahedral 1:1 layer silicates on optimum thermal activation

The negative effects of dye-contaminated wastewater on humans and the environment are well known, so the wastewater must be treated carefully before discharge into the environment. To overcome those impacts, the search for environmentally friendly and low-cost materials is essential, especially in developing countries The objective of the present study was to determine the feasibility of using bauxite

Hydrocalumite (HC) is a type of synthetic layered double hydroxide (LDH) that has many important industrial uses and is commonly synthesized by a co-precipitation method in a water:ethanol (2:3) mixture; however, atmospheric carbon dioxide interferes with the synthesis by decreasing the solubility of other gases in the reaction medium. The aim of the present study was to vary the temperature and aging

Because long-term leachate migration through a hydraulic barrier is inevitable, compacted clay and cementitious liners are commonly used as ‘active-passive’ liners to attenuate percolated leachate. The scarcity of suitable clay and because of the CO2 emitted during the production of Portland cement as well as drying shrinkage, flow rate due to consolidation, limited attenuation capacity, and chemical

Heavy metals in the environment are a problem due to their toxicity and bioaccumulation. Adsorptive removal of heavy metals by clay minerals has garnered increasing attention due to the abundance, low cost, and exceptional physicochemical properties of the clays. The purpose of the present study was to investigate the utilization of two Turkish sepiolite samples, nodular sepiolite (NS) and industrial

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