Materials Science › Biomaterials

Clay minerals and soil interactions

Works Count: 47064

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Description

This cluster of papers explores the wide-ranging applications of clay nanotubes, particularly halloysite and montmorillonite, in fields such as drug delivery, nanocomposites, biomedical applications, surface modification, encapsulation, release control, and tissue engineering.

Keywords

Clay Nanotubes; Halloysite; Montmorillonite; Drug Delivery; Nanocomposites; Biomedical Applications; Surface Modification; Encapsulation; Release Control; Tissue Engineering

Cation Exchange Capacity and Exchange Coefficients

2013-07-16

M. E. Sumner , W. P. Miller

The origin of cation exchange capacity (CEC) lies in the negative charges carried by soil particles, usually clay, organic matter and sesquioxides. An excellent parallel discussion of how the views … The origin of cation exchange capacity (CEC) lies in the negative charges carried by soil particles, usually clay, organic matter and sesquioxides. An excellent parallel discussion of how the views on soil acidity developed during this period is presented by G. W. Thomas. It is interesting to speculate what course CEC method development might have taken had the work been conducted in the humic tropical areas of Latin America, Mrica and Asia where the soils are generally highly acid. The criteria for methodology selection will be divided on a final use basis. Most measurements of exchange coefficients are made at 0.01 to 0.05 M ionic strength, largely in order to provide sufficient solution cations to effect the desired exchange with the solid phase. Arid region soils often contain carbonates and other soluble salts, resulting in complications with respect to the quantities of exchangeable cations extracted.

Handbook of clay science

2006-01-01

Faı̈za Bergaya , B. K. G. Theng , G. Lagaly

Crystal Structures of Clay Minerals and their X-Ray Identification

1980-01-01

G. W. Brindley , G. Brown

Abstract In the years 1930—1950 clay mineral identification involved mainly a combination of X-ray powder diffraction and chemical analysis with some assistance from other techniques, notably differential thermal analysis. In … Abstract In the years 1930—1950 clay mineral identification involved mainly a combination of X-ray powder diffraction and chemical analysis with some assistance from other techniques, notably differential thermal analysis. In the period 1950—1970 additional procedures have emerged including infrared analysis, electron optical methods and a variety of thermal methods. These procedures are now treated in other monographs sponsored by the Mineralogical Society and in many other publications. Despite the availability of other techniques, X-ray diffraction remains a basic tool for studying minerals and we hope that this monograph will continue to serve, as did the previous editions, both those concerned with the more academic aspects of clay mineralogy and also those, such as geologists, civil engineers and soil scientists, for whom identification and quantitative estimation of the minerals in natural clayey materials is a practical requirement.

Baseline Studies of the Clay Minerals Society Source Clays: Infrared Methods

2001-10-01

Jana Madejová , Peter Komadel

Functionalization of Halloysite Clay Nanotubes by Grafting with γ-Aminopropyltriethoxysilane

2008-09-12

Peng Yuan , Peter D. Southon , Zongwen Liu +4 more

Surface modification of natural halloysite clay nanotubes with γ-aminopropyltriethoxysilane (APTES) was investigated. Untreated and modified samples were characterized by nitrogen adsorption, X-ray diffraction, elemental analysis, thermogravimetry, transmission electron microscopy, atomic … Surface modification of natural halloysite clay nanotubes with γ-aminopropyltriethoxysilane (APTES) was investigated. Untreated and modified samples were characterized by nitrogen adsorption, X-ray diffraction, elemental analysis, thermogravimetry, transmission electron microscopy, atomic force microscopy, MAS nuclear magnetic resonance (29Si, 13C, 29Al), and Fourier transform infrared spectroscopy. The modification mechanism was found to include not only the direct grafting of APTES onto the hydroxyl groups of the internal walls, edges and external surfaces of the nanotubes but other processes in which oligomerized APTES condensed with the directly grafted APTES to form a cross-linked structure. The thermal and evacuation pretreatment conditions were found to play an important role in controlling the extent and mechanism of the modification. The extent of modification is also strongly affected by the morphological parameters of the original clay samples. This study demonstrates that the surface chemistry of halloysite nanotubes is readily modified, enabling applications in nanocomposites, enzyme immobilization and controlled release.

FTIR techniques in clay mineral studies

2003-01-01

Jana Madejová

Halloysite Clay Nanotubes for Controlled Release of Protective Agents

2008-05-01

Yuri Lvov , Dmitry G. Shchukin , Helmuth Möhwald +1 more

Halloysite aluminosilicate nanotubes with a 15 nm lumen, 50 nm external diameter, and length of 800 ± 300 nm have been developed as an entrapment system for loading, storage, and … Halloysite aluminosilicate nanotubes with a 15 nm lumen, 50 nm external diameter, and length of 800 ± 300 nm have been developed as an entrapment system for loading, storage, and controlled release of anticorrosion agents and biocides. Fundamental research to enable the control of release rates from hours to months is being undertaken. By variation of internal fluidic properties, the formation of nanoshells over the nanotubes and by creation of smart caps at the tube ends it is possible to develop further means of controlling the rate of release. Anticorrosive halloysite coatings are in development and a self-healing approach has been developed for repair mechanisms through response activation to external impacts. In this Perspective, applications of halloysite as nanometer-scale containers are discussed, including the use of halloysite tubes as drug releasing agents, as biomimetic reaction vessels, and as additives in biocide and protective coatings. Halloysite nanotubes are available in thousands of tons, and remain sophisticated and novel natural nanomaterials which can be used for the loading of agents for metal and plastic anticorrosion and biocide protection.

An Introduction to Clay Colloid Chemistry

1964-04-01

H. van Olphen

The Chemistry of Clay-Organic Reactions

1975-03-01

M. M. Mortland

A conceptual model of organo-mineral interactions in soils: self-assembly of organic molecular fragments into zonal structures on mineral surfaces

2007-06-14

Markus Kleber , Phillip Sollins , Rebecca Sutton

Environmental influences on the chemical composition of shales and clays

1971-01-01

K. H. Wedepohl

Stabilization of Soil Organic Matter: Association with Minerals or Chemical Recalcitrance?

2006-01-01

Robert Mikutta , Markus Kleber , Margaret Torn +1 more

Clay Diagenesis in Wilcox Sandstones of Southwest Texas: Implications of Smectite Diagenesis on Sandstone Cementation

1979-01-01

James R. Boles , Stephen G. Franks

ABSTRACT Sandstones and shales of the Wilcox Group (lower Eocene) in southwest Texas were examined by X-ray powder diffraction, electron microprobe, and petrographically to interpret their diagenetic history. Samples analyzed … ABSTRACT Sandstones and shales of the Wilcox Group (lower Eocene) in southwest Texas were examined by X-ray powder diffraction, electron microprobe, and petrographically to interpret their diagenetic history. Samples analyzed are from depths of 975 to 4650 m, representing a temperature range of 55°C to 210°C. No consistent trend of depositional environments is recognized with increasing depth, and mineralogic changes observed are interpreted as diagenetic. Major mineral distribution patterns are (1) disappearance of discrete smectite at temperatures >70°C, (2) gradation of mixed-layer illite/smectite to less expandable (more illitic) illite/smectite over the entire temperature range, (3) disappearance of kaolinite from 150-200°C accompanied by an increase in chlorite, and (4) replacement of calcite cement at about 117 120°C by ankerite. Calculations based on data of Hower and others (1976) indicate that the stability of smectite layers may be a function of composition. Smectites with high ratios of octahedral (Fe + Mg)/Al appear to resist conversion to illite until temperatures high enough to produce ordering are attained. A diagenetic model is proposed which involves the breakdown of detrital K-feldspar and of some smectite layers in illite/smectite to convert other smectite layers to illite. Silica and calcium released by the illitization of smectite is transferred from shales to sandstones to produce quartz overgrowths and calcite cements at temperatures as low as 60°C. Iron and magnesium released by the illitization reaction are transferred from shales to sandstones at temperatures >100°C and react with kaolinite to produce high-alumina chlorite and/or with calcite to produce ankerite.

Geothermal solute equilibria. Derivation of Na-K-Mg-Ca geoindicators

1988-12-01

Werner F. Giggenbach

MORPHOLOGICAL AND GENETIC SEQUENCES OF CARBONATE ACCUMULATION IN DESERT SOILS

1966-05-01

L. H. GILE , F. F. Peterson , Robert B. Grossman

Intercalated Clay Catalysts

1983-04-22

Thomas J. Pinnavaia

Recent advances in the intercalation of metal complex cations in smectite clay minerals are leading to the development of new classes of selective heterogeneous catalysts. The selectivity of both metal-catalyzed … Recent advances in the intercalation of metal complex cations in smectite clay minerals are leading to the development of new classes of selective heterogeneous catalysts. The selectivity of both metal-catalyzed and proton-catalyzed chemical conversions in clay intercalates can often be regulated by controlling surface chemical equilibria, interlamellar swelling, or reactant pair proximity in the interlayer regions. Also, the intercalation of polynuclear hydroxy metal cations and metal cluster cations in smectites affords new pillared clay catalysts with pore sizes that can be made larger than those of conventional zeolite catalysts.

Traditional and new applications for kaolin, smectite, and palygorskite: a general overview

2000-11-01

Haydn H. Murray

<b>X-ray Diffraction and the Identification and Analysis of Clay Minerals</b>, by D. M. Moore and R. C. Reynolds Jr., Oxford University Press, New York, 1989. 332 + xvi pp., soft cover, $24.95.

1990-08-01

Warren D. Huff

Cation site occupancy in chlorites and illites as a function of temperature

1988-12-01

‪Michel Cathelineau

Abstract The relationships between the composition and the crystallization temperature of chlorites and illites have been investigated in different geothermal fields and in particular the Los Azufres system in Mexico, … Abstract The relationships between the composition and the crystallization temperature of chlorites and illites have been investigated in different geothermal fields and in particular the Los Azufres system in Mexico, considered to be a natural analogue to experimental laboratories, as the main changes in physical and chemical conditions and mineralogy are related to progressively increasing temperature with depth. Temperature was estimated from combined geothermometric approaches, and especially from fluid inclusion studies on quartz coexisting with clays. The Al (IV) content in the tetrahedral site of chlorites, and the K content and total interlayer occupancy of illites increase with temperature. These chemical changes are mainly related to the marked decrease in the molar fraction of the Si (IV) -rich end-members (kaolinite for chlorites, and pyrophyllite for illites) which become negligible at ∼300°C. Other chemical changes, such as the variation in Fe and Mg contents, are partly influenced by temperature, but are strongly dependent on the geological environment, and consequently on the solution composition. The empirical relationships between chemical variables and temperature were calibrated from 150–300°C, but extrapolations at lower and higher temperatures seem possible for chlorites. Such geothermometers provide tools for estimating the crystallization temperature of the clays, and are important for the study of diagenetic, hydrothermal and low-T metamorphic processes.

Recent advance in research on halloysite nanotubes-polymer nanocomposite

2014-04-24

Mingxian Liu , Zhixin Jia , Demin Jia +1 more

Characterisation and evaluation of biochars for their application as a soil amendment

2010-01-01

Balwant Singh , Bhupinder Pal Singh , Annette Cowie

Biochar properties can be significantly influenced by feedstock source and pyrolysis conditions; this warrants detailed characterisation of biochars for their application to improve soil fertility and sequester carbon. We characterised … Biochar properties can be significantly influenced by feedstock source and pyrolysis conditions; this warrants detailed characterisation of biochars for their application to improve soil fertility and sequester carbon. We characterised 11 biochars, made from 5 feedstocks [Eucalyptus saligna wood (at 400°C and 550°C both with and without steam activation); E. saligna leaves (at 400°C and 550°C with activation); papermill sludge (at 550°C with activation); poultry litter and cow manure (each at 400°C without activation and at 550°C with activation)] using standard or modified soil chemical procedures. Biochar pH values varied from near neutral to highly alkaline. In general, wood biochars had higher total C, lower ash content, lower total N, P, K, S, Ca, Mg, Al, Na, and Cu contents, and lower potential cation exchange capacity (CEC) and exchangeable cations than the manure-based biochars, and the leaf biochars were generally in-between. Papermill sludge biochar had the highest total and exchangeable Ca, CaCO3 equivalence, total Cu, and potential CEC, and the lowest total and exchangeable K. Water-soluble salts were higher in the manure-based biochars, followed by leaf, papermill sludge, and wood biochars. Total As, Cd, Pb, and polycyclic aromatic hydrocarbons in the biochars were either very low or below detection limits. In general, increase in pyrolysis temperature increased the ash content, pH, and surface basicity and decreased surface acidity. The activation treatment had a little effect on most of the biochar properties. X-ray diffraction analysis showed the presence of whewellite in E. saligna biochars produced at 400°C, and the whewellite was converted to calcite in biochars formed at 550°C. Papermill sludge biochar contained the largest amount of calcite. Water-soluble salts and calcite interfered with surface charge measurements and should be removed before the surface charge measurements of biochar. The biochars used in the study ranged from C-rich to nutrient-rich to lime-rich soil amendment, and these properties could be optimised through feedstock formulation and pyrolysis temperature for tailored soil application.

DITHIONITE- AND OXALATE-EXTRACTABLE Fe AND Al AS AIDS IN DIFFERENTIATING VARIOUS CLASSES OF SOILS

1966-02-01

J. A. McKeague , John H. Day

Iron and aluminum were determined in acid ammonium oxalate extracts and in dithionite–citrate–bicarbonate extracts of a wide range of Canadian soils, several oxide and silicate minerals, and some amorphous preparations … Iron and aluminum were determined in acid ammonium oxalate extracts and in dithionite–citrate–bicarbonate extracts of a wide range of Canadian soils, several oxide and silicate minerals, and some amorphous preparations of iron or aluminum and silica. The oxalate extraction dissolved much of the iron and aluminum from the amorphous materials but very little from crystalline oxides, whereas the dithionite extraction dissolved a large proportion of the crystalline iron oxides as well as much of the amorphous materials. Oxalate-extractable iron and aluminum gave a useful indication of Bf horizon development in many soils, even if the parent materials were high in iron oxides. In one class of Gleysolic soils, however, the Bfg horizons were high in dithionite-extractable iron and low in oxalate-extractable iron. An accumulation of goethite was found in the Bfg horizon of some of these soils. In some other Gleysolic soils iron was depleted in the A horizon but there was no horizon of iron accumulation. Extraction of soils with oxalate as well as with dithionite is useful in differentiating certain classes of soils and in identifying horizons of accumulation of secondary sesquioxides.

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Mineral surfaces and soil organic matter

2003-05-19

Klaus Kaiser , Georg Guggenberger

Summary The organic carbon content of soil is positively related to the specific surface area (SSA), but large amounts of organic matter in soil result in reduced SSA as determined … Summary The organic carbon content of soil is positively related to the specific surface area (SSA), but large amounts of organic matter in soil result in reduced SSA as determined by applying the Brunauer–Emmett–Teller (BET) equation to the adsorption of N 2 . To elucidate some of the controlling mechanisms of this relation, we determined the SSA and the enthalpy of N 2 adsorption of separates with a density > 1.6 g cm −3 from 196 mineral horizons of forest soils before and after removal of organic matter with NaOCl. Likewise, we investigated these characteristics before and after sorption of increasing amounts of organic matter to four mineral soil samples, oxides (amorphous Al(OH) 3 , gibbsite, ferrihydrite, goethite, haematite), and phyllosilicates (kaolinite, illite). Sorption of organic matter reduced the SSA, depending on the amount sorbed and the type of mineral. The reduction in SSA decreased at larger organic matter loadings. The SSA of the mineral soils was positively related to the content of Fe oxyhydroxides and negatively related to the content of organic C. The strong reduction in SSA at small loadings was due primarily to the decrease in the micropores to which N 2 was accessible. This suggests preferential sorption of organic matter at reactive sites in or at the mouths of micropores during the initial sorption and attachment to less reactive sites at increasing loadings. The exponential decrease of the heat of gas adsorption with the surface loading points also to a filling or clogging of micropores at early stages of organic matter accumulation. Desorption induced a small recovery of the total SSA but not of the micropore surface area. Destruction of organic matter increased the SSA of all soil samples. The SSA of the uncovered mineral matrix related strongly to the amounts of Fe oxyhydroxides and the clay. Normalized to C removed, the increase in SSA was small in topsoils and illuvial horizons of Podzols rich in C and large for the subsoils containing little C. This suggests that micropores preferentially associate with organic matter, especially at small loadings. The coverage of the surface of the soil mineral matrix as calculated from the SSA before and after destruction of organic matter was correlated only with depth, and the relation appeared to be linear. We conclude that mineralogy is the primary control of the relation between surface area and sorption of organic matter within same soil compartments (i.e. horizons). But at the scale of complete profiles, the surface accumulation and stabilization of organic matter is additionally determined by its input.

Pyrolysis temperature induced changes in characteristics and chemical composition of biochar produced from conocarpus wastes

2013-01-08

Mohammad I. Al‐Wabel , Abdulrasoul Al-Omran , Ahmed H. El-Naggar +2 more

The effect of time on the weathering of silicate minerals: why do weathering rates differ in the laboratory and field?

2003-12-01

Art F. White , Susan L. Brantley

Oxidation of black carbon by biotic and abiotic processes

2006-08-25

Chih‐Hsin Cheng , Johannes Lehmann , Janice E. Thies +2 more

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Halloysite clay minerals — a review

2005-12-01

Emmanuel Joussein , Sabine Petit , G. Jock Churchman +3 more

Abstract Halloysite clay minerals are ubiquitous in soils and weathered rocks where they occur in a variety of particle shapes and hydration states. Diversity also characterizes their chemical composition, cation … Abstract Halloysite clay minerals are ubiquitous in soils and weathered rocks where they occur in a variety of particle shapes and hydration states. Diversity also characterizes their chemical composition, cation exchange capacity and potassium selectivity. This review summarizes the extensive but scattered literature on halloysite, from its natural occurrence, through its crystal structure, chemical and morphological diversity, to its reactivity toward organic compounds, ions and salts, involving the various methods of differentiating halloysite from kaolinite. No unique test seems to be ideal to distinguish these 1:1 clay minerals, especially in soils. The occurrence of 2:1 phyllosilicate contaminants appears, so far, to provide the best explanation for the high charge and potassium selectivity of halloysite. Yet, hydration properties of the mineral probably play a major role in ion sorption. Clear trends seem to relate particle morphology and structural Fe. However, future work is required to understand the possible mechanisms linking chemical, morphological, hydration and charge properties of halloysite.

Atlas of infrared spectroscopy of clay minerals and their admixtures

1977-03-01

H. W. van der Marel , Hans Beutelspacher

Applied Clay Mineralogy

1962-11-01

Ralph E. Grim

(1962). Applied Clay Mineralogy. Geologiska Foreningen i Stockholm Forhandlingar: Vol. 84, No. 4, pp. 533-533. (1962). Applied Clay Mineralogy. Geologiska Foreningen i Stockholm Forhandlingar: Vol. 84, No. 4, pp. 533-533.

Halloysite Clay Nanotubes for Loading and Sustained Release of Functional Compounds

2015-10-06

Yuri Lvov , Wencai Wang , Liqun Zhang +1 more

Halloysite is an alumosilicate tubular clay with a diameter of 50 nm, an inner lumen of 15 nm and a length of 600–900 nm. It is a natural biocompatible nanomaterial … Halloysite is an alumosilicate tubular clay with a diameter of 50 nm, an inner lumen of 15 nm and a length of 600–900 nm. It is a natural biocompatible nanomaterial available in thousands of tons at low price, which makes it a good candidate for nanoarchitectural composites. The inner lumen of halloysite may be adjusted by etching to 20–30% of the tube volume and loading with functional agents (antioxidants, anticorrosion agents, flame‐retardant agents, drugs, or proteins) allowing for formulations with sustained release tuned by the tube end‐stoppers for hours and days. Clogging the tube ends in polymeric composites allows further extension of the release time. Thus, antioxidant‐loaded halloysite doped into rubber enhances anti‐aging properties for at least 12 months. The addition of 3–5 wt% of halloysite increases the strength of polymeric materials, and the possibility of the tube's orientation promises a gradient of properties. Halloysite nanotubes are a promising mesoporous media for catalytic nanoparticles that may be seeded on the tube surface or synthesized exclusively in the lumens, providing enhanced catalytic properties, especially at high temperatures. In vitro and in vivo studies on biological cells and worms indicate the safety of halloysite, and tests for efficient adsorption of mycotoxins in animals' stomachs are also carried out.

The swelling of montmorillonite

1954-01-01

K. Norrish

K. Norrish, Discuss. Faraday Soc., 1954, 18, 120 DOI: 10.1039/DF9541800120 K. Norrish, Discuss. Faraday Soc., 1954, 18, 120 DOI: 10.1039/DF9541800120

Experimental determination of the fluid-absent melting relations in the pelitic system

1988-03-01

D. Vielzeuf , John Holloway

X-Ray Diffraction and the Identification and Analysis of Clay Minerals.

1999-01-01

Robert C. Graham

Cation Exchange Capacity

1982-02-01

J. D. Rhoades

Cation exchange capacity (CEC), usually expressed in milliequivalents per 100 g of soil, is a measure of the quantity of readily exchangeable cations neutralizing negative charge in the soil. Ideally … Cation exchange capacity (CEC), usually expressed in milliequivalents per 100 g of soil, is a measure of the quantity of readily exchangeable cations neutralizing negative charge in the soil. Ideally the method to use is one that measures the soil's capacity to adsorb cations from an aqueous solution of the same pH, ionic strength, dielectric constant, and composition as that encountered in the field, since CEC varies with these parameters. It is seldom practical to determine the CEC of each soil sample with reagents appropriate to its specific field solution conditions, since the latter information is not easily obtained and each CEC determination would require unique reagents. Either two or three steps are commonly used in the conventional methods of determining the CEC of soils, and potential errors exist in each step. The three steps are saturation of cation exchange sites with a specific cation, removal of excess saturating solution, and replacement of saturating cation.

A review on the adsorption of heavy metals by clay minerals, with special focus on the past decade

2016-09-12

Mohammad Kashif Uddin

Minerals in Soil Environments

1990-08-01

J. B. Dixon , S. B. Weed , R. L. PARPITT

Microaggregates in soils

2017-08-11

Kai Uwe Totsche , Wulf Amelung , Martin H. Gerzabek +7 more

Abstract All soils harbor microaggregates, i.e ., compound soil structures smaller than 250 µm. These microaggregates are composed of diverse mineral, organic and biotic materials that are bound together during … Abstract All soils harbor microaggregates, i.e ., compound soil structures smaller than 250 µm. These microaggregates are composed of diverse mineral, organic and biotic materials that are bound together during pedogenesis by various physical, chemical and biological processes. Consequently, microaggregates can withstand strong mechanical and physicochemical stresses and survive slaking in water, allowing them to persist in soils for several decades. Together with the physiochemical heterogeneity of their surfaces, the three‐dimensional structure of microaggregates provides a large variety of ecological niches that contribute to the vast biological diversity found in soils. As reported for larger aggregate units, microaggregates are composed of smaller building units that become more complex with increasing size. In this context, organo‐mineral associations can be considered structural units of soil aggregates and as nanoparticulate fractions of the microaggregates themselves. The mineral phases considered to be the most important as microaggregate forming materials are the clay minerals and Fe‐ and Al‐(hydr)oxides. Within microaggregates, minerals are bound together primarily by physicochemical and chemical interactions involving cementing and gluing agents. The former comprise, among others, carbonates and the short‐range ordered phases of Fe, Mn, and Al. The latter comprise organic materials of diverse origin and probably involve macromolecules and macromolecular mixtures. Work on microaggregate structure and development has largely focused on organic matter stability and turnover. However, little is known concerning the role microaggregates play in the fate of elements like Si, Fe, Al, P, and S. More recently, the role of microaggregates in the formation of microhabitats and the biogeography and diversity of microbial communities has been investigated. Little is known regarding how microaggregates and their properties change in time, which strongly limits our understanding of micro‐scale soil structure dynamics. Similarly, only limited information is available on the mechanical stability of microaggregates, while essentially nothing is known about the flow and transport of fluids and solutes within the micro‐ and nanoporous microaggregate systems. Any quantitative approaches being developed for the modeling of formation, structure and properties of microaggregates are, therefore, in their infancy. We respond to the growing awareness of the importance of microaggregates for the structure, properties and functions of soils by reviewing what is currently known about the formation, composition and turnover of microaggregates. We aim to provide a better understanding of their role in soil function, and to present the major unknowns in current microaggregate research. We propose a harmonized concept for aggregates in soils that explicitly considers the structure and build‐up of microaggregates and the role of organo‐mineral associations. We call for experiments, studies and modeling endeavors that will link information on aggregate forming materials with their functional properties across a range of scales in order to better understand microaggregate formation and turnover. Finally, we hope to inspire a novel cohort of soil scientists that they might focus their research on improving our understanding of the role of microaggregates within the system of aggregates and so help to develop a unified and quantitative concept of aggregation processes in soils.

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Crystal structures of clay minerals and their X-ray identification

1981-01-01

James Russell

X-ray Diffraction and the Identification and Analysis of Clay Minerals

1999-01-01

Stephen Hillier

Properties and applications of halloysite nanotubes: recent research advances and future prospects

2015-05-25

Peng Yuan , Daoyong Tan , Faïza Annabi-Bergaya

An Introduction to Clay Colloid Chemistry

1978-07-01

H. van Olphen , Pa Ho Hsu

Mineral–Organic Associations: Formation, Properties, and Relevance in Soil Environments

2014-12-17

Markus Kleber , Karin Eusterhues , Marco Keiluweit +3 more

Anion Adsorption by Soils and Soil Materials

1979-01-01

Rhys Parfitt

Physicochemical Analysis of Composites Based on Yellow Clay, Hydroxyapatite, and Clitoria ternatea L. Obtained via Mechanochemical Method

2025-06-25

Klaudia Kowalska , Ewa Skwarek | Materials

The present study describes the mechanochemical synthesis and physicochemical characterization of a novel composite material composed of yellow clay, hydroxyapatite, and Clitoria ternatea L. The synthesis was carried out using … The present study describes the mechanochemical synthesis and physicochemical characterization of a novel composite material composed of yellow clay, hydroxyapatite, and Clitoria ternatea L. The synthesis was carried out using a solvent-free, energy-efficient mechanochemical method. The composite was analyzed for its toxicity, particle size distribution, release of bioactive compounds, surface morphology, structural features, and electrokinetic properties. UV-VIS spectrophotometry revealed that the release of bioactive substances was approximately 1.5 to 3 times higher in the composite compared to control samples. Particle size analysis indicated a wide distribution ranging from 350 to 1300 nm. Nitrogen adsorption–desorption (ASAP) confirmed the porous nature of the material, while SEM and FTIR analyses verified the successful incorporation of all components. Electrokinetic studies showed zeta potential values ranging from +15 mV to –32 mV, indicating varying colloidal stability. The proposed composite demonstrates promising potential as a carrier of biologically active substances for pharmaceutical and cosmetic applications.

Correlative X-ray imaging to reveal the dissolution of nanoparticles and nutrient transport in plant foliar fertilization

2025-06-24

Chengpeng Wu , E. Kristensen , Francesco Minutello +3 more | Frontiers in Plant Science

The integration of nanotechnology in agriculture allows for more precise nutrient delivery through nanoparticles (NPs), particularly via foliar application. To mature this technology for enhancing fertilizer efficiency, it is essential … The integration of nanotechnology in agriculture allows for more precise nutrient delivery through nanoparticles (NPs), particularly via foliar application. To mature this technology for enhancing fertilizer efficiency, it is essential to shed new light on the transport and dissolution of NPs in plants. Available analytical methods struggle to address this challenge in a direct manner. We introduce correlative X-ray imaging as a novel analytical tool capable of tracking NP pathways, dissolution and hence nutrient release in plants. By utilizing three complementary X-ray techniques, we offer a unique insight into the plant processes associated with foliar fertilization. We demonstrate that small-angle X-ray scattering enables the characterization of NP size and concentration, while X-ray fluorescence imaging, maps the distribution of elements within the sample. Finally, micro-computed tomography integrates these findings into a complete three-dimensional digital representation of the plant’s microstructure, revealing regions of apparent densification associated with NP accumulation. Using freeze-dried barley plants infiltrated with nano-hydroxyapatite (nHAP), we observed rapid dissolution of NPs, and we are able to associate time and space attributes to the translocation process of nutrients up to three days following foliar application of NPs. With the first pilot study of applying correlative X-ray imaging to live plants, we sought to indicate the potential of this new analytical approach for future nano-enabled agricultural research.

Microscopic interaction mechanism between Fe-doped kaolinite and quartz: DFT calculations and experiments

2025-06-24

Huanhuan Shang , Jun Chen , Fanfei Min +3 more | Fuel

Predicting Potential Soil Nitrogen Mineralization Using Pyrolysis-coupled FTIR

2025-06-23

Sevendeep Kaur Chahal , B. L. , Adam Gillespie | Journal of soil science and plant nutrition

Analysis of the Digestion Dynamics and Dietary Risk Assessment of Fluridone in Cotton Fields via QuEChERS Coupled with HPLC

2025-06-23

Sen Wang , Ruitong Yang , Yuxuan Li +7 more | Toxics

Fluridone is a pyrrolidone soil-sealing herbicide that has been widely used in cotton fields in Xinjiang in recent years. The purpose of this study was to establish a method for … Fluridone is a pyrrolidone soil-sealing herbicide that has been widely used in cotton fields in Xinjiang in recent years. The purpose of this study was to establish a method for determining fluridone residues in cotton fields and to perform residue digestion tests, final residue analysis, and dietary risk assessment. Samples were extracted with acetonitrile, purified with primary secondary amine (PSA) and multi-walled carbon nanotubes (MWCNTs), and analyzed by high-performance liquid chromatography (HPLC). The results showed that in a certain concentration range, the concentration and peak area of fluridone showed a good linear relationship (R2 > 0.99), with limit of detection (LOD) and limit of quantification (LOQ) values of 0.00090–0.00108 mg·kg−1 and 0.0030–0.0033 mg·kg−1, respectively. The relative standard deviation (RSD) values of fluridone were 0.46% to 4.57% at the spiked level of 0.1, 0.5, and 1.0 mg·kg−1, respectively. The average daily recovery rate of fluridone was 85.08% to 95.07%. The residual levels of fluridone in cottonseed oil were below the safety threshold, indicating no significant dietary risk to consumers.

Enhancing cure characteristics, mechanical properties and swelling resistance of chloroprene rubber/natural rubber composites with halloysite nanotubes

2025-06-22

Kanniyappan Parthasarathy , S. Baskar , S. Vishvanathperumal | Journal of Rubber Research

Comparative Adsorption of Ibuprofen and Ciprofloxacin from Aqueous Solution Using Natural Bentonite Clay: Experimental and DFT Study

2025-06-21

Kelechi E Onwuka , Ahamefula A. Ahuchaogu , Okechukwu Atasie +4 more | Acta Technica Jaurinensis

This Study examines the adsorption characteristics of ibuprofen (IBP) and ciprofloxacin (CIP) onto bentonite (BT) in aqueous medium. To investigate surface properties, SEM, FTIR and XRD techniques were used to … This Study examines the adsorption characteristics of ibuprofen (IBP) and ciprofloxacin (CIP) onto bentonite (BT) in aqueous medium. To investigate surface properties, SEM, FTIR and XRD techniques were used to characterize the bentonite applied as adsorbent. The results confirmed the properties of typical bentonite clay as acceptable. Batch adsorption studies were conducted under different adsorption experimental conditions. The outcome indicated that pH, initial IBP/CIP concentration, adsorbent dosage, contact time and temperature greatly influenced IBP/CIP removal by BT in aqueous medium. Adsorption equilibrium was attained after 240 minutes of contact time for both IBP and CIP. The pseudo first order, pseudo second order, and intraparticle diffusion kinetic models were utilized to describe the kinetic data, while the Langmuir, Freundlich, and Temkin isotherm models were fitted to the equilibrium data. Results obtained from kinetic and isotherm studies showed that both the kinetic and equilibrium data were efficiently described by the pseudo second order kinetic model and Freundlich isotherm model for both pharmaceuticals respectively, as evidenced by correlation coefficients (R²) exceeding 0.98 and lower chi-square (χ²) values observed. Thermodynamic analysis indicated that the removal of IBP/CIP from aqueous solution by BT is spontaneous, endothermic, and characterized by increased disorder. Analysis from Density functional theory (DFT) was incorporated into experimental findings in other to gain clarity on distinctive characteristics of IBP/CIP adsorption. Greater chemical molecular reactivity, lower water solubility, decreased steric hindrance effects, as well as greater hydrophobicity, were factors mostly responsible for the improved ibuprofen and ciprofloxacin adsorption by bentonite.

Diffuziya shchelochnogo metalla v ferritnykh sistemakh

2025-06-21

Aleksandra Dvoreckaya , Л. Г. Аниканова , Tat'yana Sudzilovskaya +1 more | From Chemistry Towards Technology Step-By-Step

Vyyasnen mekhanizm tverdofaznogo vzaimodeistviya monoferrita kaliya s gematitom. Opredelena rol' oksida zheleza kak matritsy dlya sozdaniya dal'neishei struktury katalizatora. V protsesse ehksperimenta gotovilis' tabletirovannye obraztsy monoferrita kaliya i gematita. Tabletki … Vyyasnen mekhanizm tverdofaznogo vzaimodeistviya monoferrita kaliya s gematitom. Opredelena rol' oksida zheleza kak matritsy dlya sozdaniya dal'neishei struktury katalizatora. V protsesse ehksperimenta gotovilis' tabletirovannye obraztsy monoferrita kaliya i gematita. Tabletki pomeshchalis' v spetsial'nyi zazhim i podvergalis' termoobrabotke. Metodom iskusstvennoi metki byl issledovan mekhanizm tverdofaznogo vzaimodeistviya v sisteme KFeO2-Fe2O3. Dlya otsenki sootnosheniya produktov tverdofaznogo vzaimodeistviya monoferrita kaliya s gematitom ispol'zovali parametry q, rasschityvaemye po dannym rentgenografii. Predstavlena stolbchataya diagramma parametrov q[β"(0111)], q[β(017)] i q[Fe2O3(110)] v zavisimosti ot glubiny proniknoveniya kaliya v ob"em gematita. Analiz struktur gematita i poliferritov kaliya pozvolyaet predpolozhit', chto iony shchelochnogo metalla diffundiruyut v reshetku gematita. V obrazovavshemsya poliferrite dvizhenie kationov prodolzhaetsya mezhdu blokami sostava {Fe11O17}. Iony K+ zanimayut pravil'nye pozitsii v reshetke obrazovavshegosya poliferrita. Blizhe k granitse soprikosnoveniya tabletok raspolagaetsya sloi, bogatyi β″-poliferritom kaliya. Po mere udaleniya ot granitsy kontakta tabletok obrazuyutsya poliferrity shchelochnogo metalla so strukturami β"-glinozema i β-glinozema. Po mere udaleniya ot granitsy soprikosnoveniya tabletok soderzhanie β″-poliferrita umen'shaetsya s vozrastanie doli β- fazy. Obrazuyushchiesya poliferrity po svoei suti yavlyayutsya tverdymi ehlektrolitami, sposobnymi obespechivat' transport ionov shchelochnogo metall po opredelennym kanalam v strukture poliferrita. Privedena zavisimost' faktora f(β″), opisyvayushchego sootnoshenie β- i β″-faz v produktakh ferritoobrazovaniya, ot stepeni prevrashcheniya monoferrita kaliya v poliferrity pri termoobrabotke smesei KFeO2+2Fe2O3 pri temperature 1150 K. Pri uvelichenii stepeni prevrashcheniya f(β″) umen'shaetsya, dostigaya opredelennogo sootnosheniya β- i β″-poliferritov. Stabilizatsiya v ehtom sluchae bystree vsego dostigaetsya za schet ehnergii kogerentnogo srastaniya β- i β″-faz.

Impact of Zinc(II) Chloride Contamination on Bentonites: Formation of Simonkolleite and Effects on Porosity and Chemical Composition

2025-06-20

Edyta Nartowska , Piotr Stępień , Mária Kaňuchová | Materials

This study examines the formation of the clay mineral simonkolleite (Skl) in bentonites contaminated with zinc(II) chloride (ZnCl2), a process that has been little documented in heterogeneous systems such as … This study examines the formation of the clay mineral simonkolleite (Skl) in bentonites contaminated with zinc(II) chloride (ZnCl2), a process that has been little documented in heterogeneous systems such as contaminated bentonites. We explain the contamination mechanisms and provide new insights into the mineralogical, structural, and physicochemical transformations occurring within these materials. The objective, explored for the first time, was to assess how the ZnCl2-induced mineral phase formation influences the properties of bentonites used as sealing materials, particularly regarding changes in specific surface area and porosity. Three bentonites were analyzed: Ca-bentonite from Texas (STx-1b), Na-bentonite from Wyoming (SWy-3), and Ca-bentonite from Jelsovy Potok, Slovakia (BSvk). Treatment with ZnCl2 solution led to ion exchange and the formation of up to ~30% simonkolleite, accompanied by a concurrent decrease in montmorillonite content by 9–30%. A suite of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS), was employed to characterize these transformations. The contamination mechanism of ZnCl2 involves an ion exchange of Zn2+ within the montmorillonite structure, the partial degradation of specific montmorillonite phases, and the formation of a secondary phase, simonkolleite. These transformations caused a ~50% decrease in specific surface area and porosity as measured by the Brunauer–Emmett–Teller (BET) nitrogen adsorption and Barrett–Joyner–Halenda (BJH) methods. The findings raise concerns regarding the long-term performance of bentonite-based barriers. Further research should evaluate hydraulic conductivity, mechanical strength, and the design of modified bentonite materials with improved resistance to Zn-induced alterations.

Calcium Speciation and Solubility in Tropical Agricultural Soil Clays

2025-06-20

Apinya Saentho , Piyapas Sricharoenvech , Jörg Prietzel +2 more | Applied Clay Science

Low-cost halloysite-fly ash composite for the removal of pharmaceuticals, dyes and surfactants from contaminated water

2025-06-20

Agnieszka Solińska , Grzegorz Rzepa , Mateusz Marzec | Journal of Environmental Management

Environmental contamination by dyes, pharmaceuticals, and surfactants is a global concern, highlighting the urgent need for effective removal methods. We investigated a low-cost composite based on halloysite (HAL) and fly … Environmental contamination by dyes, pharmaceuticals, and surfactants is a global concern, highlighting the urgent need for effective removal methods. We investigated a low-cost composite based on halloysite (HAL) and fly ash (FA) as a adsorbent for removal of surfactant: sodium dodecylbenzenesulfonate (SDBS); dyes: Remazol brilliant blue r (RBBR), Rhodamine b (RB); pharmaceuticals: sulfamethoxazole (STX), ibuprofen (IB) from single adsorbate solutions and real wastewater. The dualistic approach was employed: advanced instrumental analysis for adsorbent-sorbate interactions study and sorption experiments conditions (effect of initial organic compounds concentration, the solution pH) for sorption efficiency assessment. The characterization of adsorbents included X-ray diffraction, X-ray fluorescence and X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy. The composite with a 20:80 ratio of HAL to FA exhibited the best sorption properties. The sorption capacity for RBBR, RB exceeded 20 mg/g and 4 mg/g, respectively, while for IB, STX and SDBS the sorption capacities were above 0.9, 0.3, and 8.5 mg/g, respectively. In general, slightly acidic conditions (pH 5-7) promoted RBBR, RB and STX adsorption; alkaline conditions (pH > 9) promoted IB adsorption. The X-ray photoelectron spectroscopy revealed a complex physical adsorption process involving dispersion forces, hydrogen and electrostatic bonding. The studies showed that the eco-friendly and inexpensive composite can simultaneously uptake organic compounds from wastewater. Although the competition effect of inorganic/organic molecules affected the sorption efficiency, the removal of SDBS from wastewater reached 100 %. Further research will focus on investigating granulated composites in dynamic column systems to advance purification technologies.

Study on the adsorption mechanism of ricinoleate and oleate on kaolinite and quartz surfaces

2025-06-19

Chuilei Kong , Lingyun Liu , Xianglin Yang +1 more | Minerals Engineering

Composition, Structure and Properties of Vermiculite from the Tebinbulok Deposit in Karakalpakstan, Uzbekistan

2025-06-19

Jabbarbergenov Madiyar Jollibayevich , Madenov Berdimurat Dauletmuratovich , Abdurasul Abdumalikovich Mamataliev +1 more | Chemical Science International Journal

In this research, the chemical composition and physicochemical properties of vermiculite from the Tebinbulak deposit, located in the Karauzyak district of the Republic of Karakalpakstan, were comprehensively investigated. The analyses … In this research, the chemical composition and physicochemical properties of vermiculite from the Tebinbulak deposit, located in the Karauzyak district of the Republic of Karakalpakstan, were comprehensively investigated. The analyses conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) revealed that the studied vermiculite belongs to the class of layered magnesium–aluminum and magnesium–iron aluminosilicates. The crystal structure of the mineral contains interlayer water molecules, which contribute to its distinctive physicochemical behavior. Owing to its broad range of applications—including in construction, the food and chemical industries, oil and gas extraction, nuclear energy, environmental protection, metallurgy, mechanical engineering, railway car manufacturing, shipbuilding, mining, and agriculture—the industrial relevance and economic value of vermiculite are steadily increasing.

New insight into the geochemical behavior of alkali and alkaline earth metals in a frequently subsampled clay pit sample with and without Al-normalization

2025-06-19

| Glasnik hemicara i tehnologa Bosne i Hercegovine

Clays are fine-particle-size materials (less than 2 μm) comprised mainly of clay minerals, which are hydrated aluminum silicates with associated alkali and alkaline earth elements. The small particle size and … Clays are fine-particle-size materials (less than 2 μm) comprised mainly of clay minerals, which are hydrated aluminum silicates with associated alkali and alkaline earth elements. The small particle size and complex porous structure result in a high specific surface area, which allows strong physical and chemical interactions with dissolved species. Metals can also be incorporated within the clay structure, which can be made of octahedral and/or tetrahedral sheets. Depending on the composition of the tetrahedral and octahedral sheets, the layer will have no charge or will have a net negative charge. If the layers are charged, this charge is balanced by interlayer cations. The recent research of metals in clays mainly focused on heavy metals, while investigations of light metals are rather rare. For the investigation of the behavior of alkali and alkaline earth metals in clay samples, 110 subsamples of cored samples were taken. The total contents of potassium (K), magnesium (Mg), calcium (Ca), sodium (Na), strontium (Sr), and barium (Ba) were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Descriptive statistics were conducted using maximum, minimum, average, and median values. Correlation and PCA analysis with and without Al-normalization were calculated to determine the different behavior of metals, The contents of metals lie in the following sequence: K>Mg>Ca>Na>Ba>Sr. The highest correlation between metals was found between Mg and K (r=0.87) and Ba and Sr (r=0.65). PCA analysis revealed two subgroups: 1) K, Mg, Na. 2) Ba, Sr. After the Al normalization was applied, Ba and Sr showed the highest correlation (r=0.81). Ca did not significantly contribute to any of the PCA subgroups, suggesting a possible different source and behavior.

Novel glauconite compounds improve soil properties and sugar beet (<i>Beta vulgaris</i> L.) yields in saline soils

2025-06-18

Mahmoud El‐Sharkawy , Modhi O. Alotaibi , Esawy Mahmoud +4 more | PeerJ

Sugar beet is essential for sugar production, supporting food industries and renewable energy resources. A two-season field experiment (2021/2022 and 2022/2023) evaluated the effects of different potassium (K) sources, including … Sugar beet is essential for sugar production, supporting food industries and renewable energy resources. A two-season field experiment (2021/2022 and 2022/2023) evaluated the effects of different potassium (K) sources, including traditional potassium sulfate (K), glauconite powder (G), and foliar glauconite extracts (20- and 40-mL L-1) extracted with sulfuric acid (GS), humic acid (GH), or hot water (GW), on soil properties, sugar beet yield, and sugar quality in saline soils. The results showed that GH and G treatments significantly improved soil properties by reducing electrical conductivity (EC), exchangeable sodium percentage (ESP), and bulk density (BD), while increasing organic matter (OM) and infiltration rate (IR). The application of glauconite extracted by humic acid in 40 mL (GH2) treatment improved soil nutrient availability, notably increasing nitrogen (by 73.4%), potassium (by 137.2%), cupper (by 219.7%), and manganese (by 316.7%) compared to control, while GS2 enhanced ferrous (by 213.7%) and zinc (by 363.7%). GH2 application led to remarkable improvements in sugar beet yield, with average increases in root yield (94.84%), shoot yield (100.45%), total sugar yield (137.22%), and sucrose (20.5%) compared to the control, whereas GW treatments showed the least improvements. Despite GW recording the lowest sugar impurities, GH2 recorded the lowest alkalinity level. Advanced analytical techniques such as heatmaps, self-organizing maps (SOM), and while non-metric multidimensional scaling (NMDS) analysis revealed strong positive correlations between soil properties, sugar beet responses and sugar quality attributes. These findings underscore the potential incorporation of new innovative cost-effective alternative foliar amendment derived from glauconite rock-waste extraction with humic acid highlighting a sustainable agricultural strategy for managing soil health and crop productivity contributing to food security and environmental sustainability.

Chemical and Mineralogical Characterizations of Different Kaolinitic Clays from Burkina Faso: Feasibility for the Synthesis of Geopolymer Binders

2025-06-17

Seick Omar Soré , Philbert Nshimiyimana , Adamah Messan +3 more | Geosciences

Researchers are exploring eco-friendly alternatives to Portland cement, such as geopolymers, which require reactive aluminosilicate sources. This study evaluated the reactivity of six calcined clays (heated at 700 °C) in … Researchers are exploring eco-friendly alternatives to Portland cement, such as geopolymers, which require reactive aluminosilicate sources. This study evaluated the reactivity of six calcined clays (heated at 700 °C) in the presence of an alkaline solution. The calcined samples from kaolinite quarries in Kamboinsé, Kandarfa, Saaba, Sabcé, Selogo, and Tougou were subjected to chemical and mineralogical analyses. The results indicated a high aluminosilicate content (>50%), with kaolinite reaching up to 83.1%, and an amorphous fraction of up to 31.8%, a key factor influencing reactivity. Geopolymer pastes, prepared using a 12 M NaOH solution and each of these calcined clays, exhibited varying setting times: 24 h for the Saaba clay (the most reactive) compared with 48 h or even up to 7 days for the least reactive. The evaluation of the compressive strength of the geopolymer pastes revealed varying performances depending on the composition of clay. The Saaba clay showed the highest strength (14 MPa), attributed to its high kaolinite content (83.1%) and amorphous phase (31.8%), and thus reactivity. This was followed by Kamboinsé with 10.5 MPa (58.3% kaolinite; 24.3% amorphous phase), Selogo with 4.6 MPa (42.9%; 20.4%), Tougou with 1.4 MPa (44.1%; 20.4%), Kandarfa with only 0.7 MPa (31.3%; 19.2%), and Sabcé, which did not set with 0 MPa (24.1%; 13.7%). A discussion between the chemical and mineralogical compositions of the different clays and the mechanical characteristics of the synthesized pastes highlighted the importance of kaolinite content and its amorphous nature on the reactivity of the geopolymer binders. These findings highlight its potential for applications such as stabilized bricks or geopolymer concrete, offering a low-carbon alternative to traditional materials.

Nano biochar enhances organic carbon accumulation, molecular complexity, and salt leaching in saline–alkali soil columns

2025-06-16

Yue Xie , Tiantian Bai , Yongqi Zhang +3 more | Journal of Environmental Management

Sea Sand as a Silica Source to Hydrothermally Synthesize Analcime

2025-06-16

Wei Xie , Hao Ma , Changqun Cao +5 more | Materials

Analcime has demonstrated potential for a variety of applications in technology, especially in adsorption and heterogeneous catalysis. In this study, synthetic analcime was investigated by using sea sand as a … Analcime has demonstrated potential for a variety of applications in technology, especially in adsorption and heterogeneous catalysis. In this study, synthetic analcime was investigated by using sea sand as a silica source. Sea sand was first treated with HNO3 and NaOH. The pretreated sea sand as the silica resource and Al(NO3)3 as the aluminum source were used for the hydrothermal synthesis of analcime with different ratios of Si/Al and Na/Si. The products obtained under different conditions were characterized by X-ray diffraction. The results showed that analcime synthesized using acid-treated sea sand was mixed with other impurities, such as quartz and sodalite. Pure analcime was obtained using alkali-treated sea sand as the silica source. The analcime prepared under an optimized synthesis condition was further investigated via SEM, FT-IR, and TG. The particle size of the prepared analcime ranged from 40 to 50 μm. The adsorption ability of analcime was studied, and the Cu2+ adsorption process was found to follow a pseudo-second-order kinetic model.

Theoretical Study on Impact of Chemical Composition and Water Content on Mechanical Properties of Stratlingite Mineral

2025-06-16

Daniel Tunega , A. Zaoui | Minerals

Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of … Stratlingite is known as one of the hydration products of aluminum-rich cements. Its microstructure and, consequently, mechanical properties, depend on the Al/Si ratio and hydration conditions. The layered structure of stratlingite is characterized as defected, with vacancies in the aluminosilicate layer. This study uses density functional theory calculations on different stratlingite models to show how chemical composition, water content, and structural defects affect its mechanical properties. The developed models represent structures with full occupancy, with little or no content of structural water, and with vacancies in the aluminosilicate layer. It was shown that the full occupancy models have the highest toughness and are strongly anisotropic. The calculated bulk modulus (BH) of the models with full occupancy was about 40 GPa, being in the typical range for calcium aluminosilicate minerals. The water loss led to an increase in BH by approximately 40% compared to the models with full occupancy. In contrast, the models with vacancies exhibited a decrease in BH of about 30%. In models with the high silicon content (Al/Si ratio of 1/4), BH, Young’s (EH), and shear (GH) moduli decreased in a range 15%–30% compared to the models with an Al/Si ratio of 2/3 of Al/Si. Finally, according to Pugh’s ratio (BH/GH), which serves as a criterion for brittle–ductile transition (1.8), the models with full occupancy exhibit a brittle behavior, whereas the defected structures are closer to ductile. This could explain the elastic behavior of stratlingite binder in concretes. Generally, the calculations showed that all investigated parameters (chemical composition, water content, and structural defects) have a significant impact on the mechanical properties of stratlingite minerals.

The multifaceted role of zeolites in modern agriculture and environmental management

2025-06-14

Sayantika Sarkar , Pravin Kumar Upadhyay , Tarik Mitran +7 more | Journal of Plant Nutrition

Hydrothermal smectite synthesis in presence of Glycine: Synergistic chemical evolution

2025-06-14

Rihab Fkiri , Fabien Baron , Clément Comminges +3 more | Applied Clay Science

Controlling Impurity Effects in Phosphogypsum Calcination: A Combined Regression and DFT Study for Optimizing β-Hemihydrate Gypsum Production

2025-06-13

Manman Lu , Wei Ma , Ze Guo +3 more | Materials Research Express

Abstract The preparation of β-hemihydrate gypsum by calcining is an effective way to consume phosphogypsum (PG) on a large scale at low cost. However, the impurities in the PG will … Abstract The preparation of β-hemihydrate gypsum by calcining is an effective way to consume phosphogypsum (PG) on a large scale at low cost. However, the impurities in the PG will affect the dehydration process of dihydrate gypsum, leading to a reduced content of β-hemihydrate gypsum in the final product. Unfortunately, the extent and mechanisms by which these impurities influence the dehydration process remain unclear. This study investigates the effects of four typical impurities SiO2, NaF, Ca3(PO4)2, graphite on gypsum phase distribution through calcination experiments. Furthermore, the degree of impact and underlying mechanisms of these impurities on the dehydration process were further analyzed using regression analysis and density functional theory (DFT) calculations. The results indicate that when the concentrations of Ca₃(PO4)₂, NaF, SiO₂, and graphite are below 0.6%, 0.3%, 1.0%, and 0.1%, respectively, their influence on the β-hemihydrate gypsum content is minimal. The regression analysis revealed that the effect degree of the four impurities on the β-hemihydrate gypsum content in product is in the order of SiO2 ＞ NaF ＞ Ca3(PO4)2 ＞ Graphite. The primary mechanism is related to differences in the adsorption energies of water molecules on the lattice planes of the impurities. Water molecules are more readily adsorbed onto SiO₂ surfaces, where they subsequently react with β-hemihydrate gypsum during the later stages of dehydration, causing rehydration to dihydrate gypsum.&#xD;

The colloidal stability of natural allophane in alkaline aqueous environment containing different oxyanions

2025-06-13

Maolin Li , T. Sugimoto , Yuji Yamashita +1 more | Journal of Dispersion Science and Technology

Structure refinement and anisotropic atomic displacement parameters of 1M Illite: Rietveld and pair distribution function analysis using synchrotron X-ray radiation

2025-06-12

Seungyeol Lee | Journal of Applied Crystallography

Illite, a widespread clay mineral, plays a pivotal role in geological processes, notably as an indicator in diagenetic and hydrothermal alteration environments, and possesses significant industrial relevance in applications including … Illite, a widespread clay mineral, plays a pivotal role in geological processes, notably as an indicator in diagenetic and hydrothermal alteration environments, and possesses significant industrial relevance in applications including ceramics, construction and catalysis. However, challenges including its nanoscale crystallinity, structural disorder and frequent interstratification with other clay minerals have hindered detailed structural characterization using conventional X-ray diffraction (XRD) techniques. This study employs integrated synchrotron XRD and pair distribution function (PDF) analysis to elucidate the crystal structure of the 1M illite polytype, yielding the first determination of its anisotropic atomic displacement parameters ( U aniso ). These U aniso parameters provide critical insights into atomic dynamics and static disorder within the structure, enabling a more refined understanding of structure–property relationships. This integrated approach, combining synchrotron XRD, Rietveld refinement and PDF analysis, yields a comprehensive structural characterization, capturing both average crystallographic and local atomic arrangements. Considering illite's widespread geological occurrence and industrial importance, this high-precision structural dataset, especially the determined U aniso values, provides a crucial benchmark for future modeling and simulation efforts targeting accurate prediction of its physicochemical behavior.

Al(NO3)3/SiO2 Synthesized from Rice Husk Ash Increases Isomer Separation Efficiency of Natural Beta-Caryophyllene

2025-06-09

| Biointerface Research in Applied Chemistry

Beta-caryophyllene is a sesquiterpene found in almost all plant essential oils that provide spacious biological activities. However, this compound is generally mixed with its isomers, leading to decreased caryophyllene purity. … Beta-caryophyllene is a sesquiterpene found in almost all plant essential oils that provide spacious biological activities. However, this compound is generally mixed with its isomers, leading to decreased caryophyllene purity. Rice husk offers a sustainable source of silica that can be doped with metal ions to increase the separation efficiency. This study aimed to synthesize metal ion-modified silica from rice husk and evaluate its effectiveness in separating beta-caryophyllene from its isomers. Silica was extracted and modified with metal ions (Al(NO3)3, CuSO4, FeNO3, and ZnNO3) using sol-gel and reflux methods. The resulting materials were characterized by XRD, FTIR, and SEM-EDX. XRD analysis confirmed the amorphous nature of the silica, indicated by the presence of a peak at 2theta 20-25°, while FTIR spectroscopy revealed the presence of characteristic silanol (O-H) and siloxane (Si-O-Si) groups. SEM-EDX analysis demonstrated successful metal ion doping and provided insights into the morphology and elemental composition of the modified silica, which indicated the presence of Al, Cu, Fe, and Zn with a round-ball form. The separation efficiency of the metal ion-modified silica was assessed using thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). Al(NO₃)₃-modified silica showed the most promising results as a stationary phase for beta-caryophyllene purification. Column chromatography using this material achieved a 99% purity of beta-caryophyllene, as confirmed by GC-MS analysis. This study demonstrates the potential of metal ion-modified silica derived from rice husk as an effective and sustainable material for the separation of natural product isomers.

Microwave-Assisted expansion of vermiculite for Congo red adsorption

2025-06-02

Phuong Anh Cao , Khanh Nguyen , Thuy Hang Nguyen +3 more | CRC Press eBooks

The Regolith-hosted Clay REEs Leaching Effects by Mechanical Grinding and at Low Temperature: An Analogy on Treatment Method

2025-06-01

Hassan Nasir Mangi , Liqiang Ma , Ruan Chi +6 more | Journal of Materials Research and Technology

Incorporating Halloysite Nanotubes@Malva extract into Starch-Hyaluronic Acid Nanocomposite Films Containing Carbon Quantum Dots for Antibacterial Application

2025-06-01

Mahmoud Abbaszadeh , Nasser Arsalani , Fahimeh Kazeminava +1 more | Carbohydrate Polymer Technologies and Applications

Production of potassium silicate from palm oil mill boiler ash for liquid fertilizer: effect of re-ashing pretreatment and extraction conditions

2025-06-01

H. Hoerudin , Tatang Hidayat , Nurdi Setyawan +7 more | IOP Conference Series Earth and Environmental Science

Abstract Potassium silicate is an essential fertilizer for the optimum growth and yield of many silica-accumulating crops. Research on producing LPS from agro-industrial wastes is limited. This study investigated the … Abstract Potassium silicate is an essential fertilizer for the optimum growth and yield of many silica-accumulating crops. Research on producing LPS from agro-industrial wastes is limited. This study investigated the effects of re-ashing pretreatment, potassium hydroxide (KOH) concentration, and extraction time on the yield and properties of liquid potassium silicate (LPS) from palm oil mill boiler ash (POMBA), assessing its potential as a liquid fertilizer. POMBA, with or without re-ashing pretreatment, was extracted using KOH to determine the necessity of re-ashing. The selected raw material was extracted with varying KOH concentrations (6%, 8%, 10%) and extraction times (60, 90, 120min). Extraction of POMBA with re-ashing pretreatment, 6% KOH, and 120min extraction time significantly produced LPS with the highest available SiO 2 concentration (18.50%) (p<0.05) and a 12.98% yield. This available SiO 2 concentration was comparable to that of commercial liquid silica fertilizer (20.71%). The LPS produced also contained 19.22% total potassium (as K 2 O). The properties of POMBA-derived LPS met the Indonesian minimum technical requirements for liquid compound fertilizers, highlighting the significant potential of POMBA as a cost-effective and sustainable source of liquid fertilizer.

Clay Minerals in Upper Pleistocene Sediments from the Center of a Hydrothermal System, Hole ODP 1036A, Middle Valley, Juan De Fuca Ridge, Pacific Ocean

2025-06-01

Victor B Kurnosov , B. A. Sakharov , И. А. Морозов +1 more | Russian Journal of Pacific Geology

Geopolymerization of Halloysite Clay Nanotubes Mixed with Hydroxypropyl Cellulose for Development of Composite Films with Flame Resistance Properties

2025-06-01

Alessandro Lo Bianco , Martina Maria Calvino , Giuseppe Lazzara +2 more | Ceramics International

Mineral-bound lipid formation in soils and sediments: the importance of microbial pathways

2025-06-01

Hongye Pei , Huan Yang , Yakov Kuzyakov +3 more | Soil Biology and Biochemistry

Deep Roots Supply Reactivity and Enhance Silicate Weathering in the Bedrock Vadose Zone

2025-06-01

Ivan Osorio‐Leon , Daniella Rempe , Jon K. Golla +2 more | AGU Advances

Abstract In upland environments, roots commonly extend deep below soil into partially saturated bedrock. This Bedrock Vadose Zone (BVZ) has been shown to store and circulate water, host organic carbon … Abstract In upland environments, roots commonly extend deep below soil into partially saturated bedrock. This Bedrock Vadose Zone (BVZ) has been shown to store and circulate water, host organic carbon respiration and serve as a critical source of rock‐derived nutrients. However, the extent to which deep roots influence chemical weathering rates remains poorly understood. Here, we report 4 years of depth‐resolved major ion chemistry over a 16‐m thick BVZ hosting a deep rhizosphere in a catchment subject to a Mediterranean climate. These data allow development and validation of a reactive transport model (RTM), revealing that the timescales of water storage and drainage in the BVZ are sufficient to facilitate substantial chemical weathering of the shale bedrock. However, observed solute concentrations are only reproduced by the RTM when we explicitly include measured rates of production meters below soil driven by the deeply rooted forest. By combining direct observations and a process‐based RTM we conclude that the carbon respiration promoted by deep roots significantly enhances chemical weathering rates in the BVZ, constituting 43% 3% of total solute flux from the base of the BVZ to the water table.

The Clay Minerals Society

2025-06-01

| Elements