Applied Clay Science最新文献

{"title":"Adsorption of heavy metals using cysteine-modified pillared montmorillonite: Mechanisms and characteristics","authors":"Chao Hu ,&nbsp;Feiyu Teng ,&nbsp;Xinjia Yin ,&nbsp;Pu Wang ,&nbsp;Bianyang He ,&nbsp;Lei Zhu","doi":"10.1016/j.clay.2025.107923","DOIUrl":"10.1016/j.clay.2025.107923","url":null,"abstract":"<div><div>Montmorillonite enhanced its adsorption performance through the modification with organic and inorganic materials. Among various modifiers, cysteine was known for its significant ability to bind heavy metals due to the presence of thiol and amino functional groups. This study used X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and a series of adsorption experiments to examine the interaction between FeCl₃-AlCl₃ pillared montmorillonite (P<img>Mt) and cysteine (Cys), and to investigate the adsorption characteristics and mechanisms of the composite of pillared montmorillonite and cysteine (P-Mt-Cys) toward heavy metals. The XRD and FTIR results indicated that cysteine intercalated into the layers of the pillared montmorillonite and, through its functional groups, dominated the surface of the P-Mt-Cys composite. The pillaring material slowed down the rate at which cysteine entered the montmorillonite and established pH 5.0 as the optimal electrochemical condition for cysteine intercalation. The adsorption of cysteine onto P<img>Mt followed a pseudo-second-order kinetic model, and the Dubinin-Radushkevich (D-R) isothermal adsorption model provided a good fit for the data. In the pH range of 5.0–5.5, P-Mt-Cys exhibited superior adsorption of Cu(II) compared to unmodified Mt. and P<img>Mt. The adsorption of Cu(II) on P-Mt-Cys reached equilibrium within 120 min. The Freundlich isothermal adsorption model best described the multilayer adsorption of Cu(II), with a maximum adsorption capacity of 27.02 mg g⁻¹ at an equilibrium concentration of 81.91 mg L⁻¹. The adsorption process was exothermic and spontaneous, and the adsorption amount decreased as the temperature increased. Additionally, both the enthalpy change and entropy change were negative. These findings established the foundation for understanding the adsorption characteristics of heavy metals and offered a reference for further studies on the Mt-Cys-heavy metal system.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107923"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fixation and liberation of smectite interlayer cations under dry and wet conditions","authors":"Artur Kuligiewicz ,&nbsp;Reiner Dohrmann ,&nbsp;Stephan Kaufhold ,&nbsp;Adam Zięba ,&nbsp;Arkadiusz Derkowski","doi":"10.1016/j.clay.2025.107914","DOIUrl":"10.1016/j.clay.2025.107914","url":null,"abstract":"<div><div>The aim of the present study was to examine changes in the layer charge (LC) of smectite heated for an extended period of time under two contrasting conditions: wet (hydrothermal experiments) and dry (oven heating). Understanding smectite's behavior at elevated temperatures is crucial, e.g., in the case of high-level radioactive waste storage facilities, where bentonites (smectite-rich rocks) are planned to be used as one of the barriers. A set of two montmorillonites and one beidellite in four cationic forms, Mg²⁺, Ca²⁺, Fe²⁺, and K⁺, was heated at 100 or 200 °C for up to 157 days. In addition, LC regeneration tests involving cation exchange and hydrothermal treatment of oven-dried samples were performed. LC was measured using the spectroscopic OD method, whereas X-ray diffraction was used to verify the changes detected by the OD method. In the dry-heating experiments, most samples showed stable LC values up to 146 days of heating, except the LC decrease for Fe²⁺ and Mg²⁺-exchanged montmorillonite, which was interpreted as resulting from the formation of inner-sphere complexes and/or penetration of these cations into the octahedral sheet. The LC values of samples after hydrothermal experiments were more variable, possibly due to the cation exchange, and dissolution and reprecipitation processes. In the case of Fe²⁺-exchanged samples reacted hydrothermally at 200 °C, kaolinite was formed at the expanse of smectite, and collapsed interlayers formed in K⁺-exchanged samples reacted under the same conditions. Cation exchange and hydrothermal treatment were not always successful in restoring the initial LC of samples, however, hydrothermal rehydration reaction was efficient in the case of samples dried at 100 °C. The paper presents the mechanism of interlayer cations fixation and liberation, which change the properties of smectite-rich bentonite barriers for nuclear waste disposal under partially dry vs. water-saturated conditions. Reversible after drying at 100 °C and irreversible after 200 °C cation fixation match common temperature limits of bentonite exposure to radioactively-produced heat.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107914"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and characterization of clay composites with Zeolitic imidazolate framework for application as an herbicide adsorbent","authors":"Tainara C. Assis ,&nbsp;Bluma G. Soares ,&nbsp;Luiz C. Bertolino","doi":"10.1016/j.clay.2025.107926","DOIUrl":"10.1016/j.clay.2025.107926","url":null,"abstract":"<div><div>Glyphosate is one of the most widely used herbicides globally; however, its extensive application is linked to environmental contamination and the onset of various human diseases. Therefore, developing effective strategies to remove glyphosate (GLY) from aqueous effluents in crucial. Zeolitic imidazole frameworks (ZIFs), a subclass of metal-organic framework (MOF) formed with imidazole ligands, closely resemble natural zeolites in structure. Their unique textural properties make them suitable candidates as adsorbents. In this study, a Cu (II)-based ZIF was synthesized in the presence of clay minerals, specifically palygorskite (PAL) and Na⁺ montmorillonite (CloNa), and its adsorption efficiency for GLY was evaluated. The CloNa/Cu-MOF hybrid demonstrated the highest GLY adsorption efficiency among the materials tested, reaching a value of 63 mg g⁻¹ at pH 4, 25 °C, and an initial GLY concentration of 500 mg L⁻¹. This high efficiency was attributed to the improved textural properties, thermal stability, and stability in aqueous media of CloNa/Cu-MOF hybrid. GLY adsorption followed the pseudo-second-order kinetic model, and the isotherm study revealed a favorable adsorption profile, with the best fit to the Langmuir model. Q_max values ranged from 20.04 to 277.77 mg g⁻¹ for the different studied temperatures. The thermodynamic analysis confirmed that the adsorption process is endothermic and occurs spontaneously.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107926"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on the physical and mechanical properties of metakaolin-based geopolymers: Effects of aging and confining pressure","authors":"Wei Xu ,&nbsp;Matthieu Briffaut ,&nbsp;Nicolas Gay ,&nbsp;Jianfu Shao","doi":"10.1016/j.clay.2025.107910","DOIUrl":"10.1016/j.clay.2025.107910","url":null,"abstract":"<div><div>Geopolymers are more and more investigated as a promising and sustainable green concrete solution for many engineering applications. A thorough characterization of their physical and mechanical properties is crucial for safety and durability analysis of related structures. This paper investigates the physical and mechanical behaviors of metakaolin-based geopolymer at different ages under uniaxial and triaxial compression conditions. The present study first focuses on the setting time, bulk density, porosity, permeability, and pore structure of selected geopolymer specimens. The emphasis is then placed on the characterization of elastic properties, failure strength and patterns of material through uniaxial and triaxial compression tests. The study reveals that with increasing curing age, the bulk density, porosity, pore volume, and permeability decrease, while one obtains an increase of failure strength, Young’s modulus, internal cohesion, and friction angle. Higher confining pressure enhances failure strength and ductility, shifts cracking mode from axial splitting to inclined shearing, and induces irreversible pore structure changes. Permeability and mechanical behavior show nonlinear dependence on confining pressure. These results bring some new insights on the effects of age and confining pressure on the microstructure, mechanical and transport properties of metakaolin-based geopolymers, potentially supporting engineering design and modeling.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107910"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the potential toxicity of respirable halloysite elongate mineral particles: Insights from the Fibre Potential Toxicity Index (FPTI) model","authors":"Alessandro F. Gualtieri ,&nbsp;Laurie Glossop ,&nbsp;Daniele Malferrari ,&nbsp;Elena Castellini ,&nbsp;Magdalena Lassinantti Gualtieri ,&nbsp;Miriam Hanuskova ,&nbsp;Luca Nodari ,&nbsp;Jordan Ogor ,&nbsp;Riccardo Fantini","doi":"10.1016/j.clay.2025.107917","DOIUrl":"10.1016/j.clay.2025.107917","url":null,"abstract":"<div><div>Halloysite is a member of the kaolin group, with an ideal chemical composition of Al₂(OH)₄Si₂O₅⋅2H₂O, displaying wide and diverse industrial application spanning from traditional ceramics to drug delivery. Halloysite often occurs as elongate mineral particles (EMPs) with nanometer-size tubular, cylindrical or fibrous shape. Despite these features and its extensive use, the International Agency for Research on Cancer (IARC) has not yet evaluated halloysite for its potential carcinogenicity. Existing literature only focused on its toxicity following oral administration mostly in a pharmaceutical contexts, but findings remain inconclusive.</div><div>In this study, a commercially available halloysite from Matauri Bay (North Island, New Zealand) was investigated to provide further insight into potential occupational exposure to airborne nano-particles in the ceramic industry. A comprehensive characterization of the sample was performed using XRPD, TGA-DTA, XRF-WDS, BET, particle size distribution, SEM, TEM, Mössbauer and UV–Vis spectroscopies. This multi-technique approach permitted to determine its toxicity potential through the Fibre Potential Toxicity Index (FPTI) model, which had already proven robust in evaluating the hazardousness of respirable mineral fibres. Results indicated that the sample contains approximately 90 wt% halloysite, with minor quartz and cristobalite. Halloysite nanotubes are respirable but not “regulated fibres” with a FPTI value of 1.92(0.10), comparable to that of non-carcinogenic mineral fibres suggesting, with caution, that halloysite is a nanomaterial with low toxicity. Although the study focused on samples from a specific locality, the results should be considered applicable to halloysite samples from any quarry; nevertheless, it should be noted that halloysite from this deposit contains respirable quartz and cristobalite which are a IARC <em>Group 1</em> known human carcinogens.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107917"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial mineralization of struvite by using talc and its implications for phosphorus recovery","authors":"Xingtong Chen ,&nbsp;Tianlei Zhao ,&nbsp;Bing Li ,&nbsp;Yihe Qin ,&nbsp;Xiaoman Li ,&nbsp;Run Yuan ,&nbsp;Jingjing Chen ,&nbsp;Han Li ,&nbsp;Haiming Huang","doi":"10.1016/j.clay.2025.107927","DOIUrl":"10.1016/j.clay.2025.107927","url":null,"abstract":"<div><div>Microbial mineralization of struvite is an ideal route to recover nitrogen and phosphorus from wastewater, but expensive magnesium sources limit its application. In this context, <em>Shewanella oneidensis</em> MR-1 was chosen as a model microorganism to investigate the feasibility of using inexpensive and abundant talc as a magnesium source for the microbial mineralization of struvite. The results showed that talc was able to provide magnesium ions for strain MR-1 to induce struvite mineralization, producing prismatic struvite with a purity of up to 78.42 mass%. With increasing ball-milling times from 0 to 90 min, the struvite purity gradually increased from 15.08 mass% to 51.36 mass%, and Mg transformation efficiency of talc increased from 3.95 % to 20.68 %. These findings indicate that mechanical activation can significantly improve the reactivity of talc in the microbial mineralization process. With increasing talc additions from 0.2 g/L to 2.0 g/L, the struvite purity gradually decreased from 78.42 mass% to 41.68 mass%, and Mg transformation efficiency of talc ranged from 17.54 % to 28.02 %. These findings revealed that excess talc could not be effectively converted into struvite and that excess talc also reduced struvite purity. Dissolution experiments revealed that organic matter such as amino acids in the culture medium and ammonium ions produced by strain MR-1, promoted the dissolution of magnesium ions in talc. This study deepens the understanding of microbial-mineral interactions and provides an economically feasible pathway for the removal and recovery of organic nitrogen and organophosphorus in eutrophic waters.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107927"},"PeriodicalIF":5.3,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tailored aluminum coordination in metakaolin: A defect-engineering strategy for high-performance tribocatalysis","authors":"Kai Wang ,&nbsp;Zhu Shu ,&nbsp;Yuchen Wen ,&nbsp;Jun Zhou ,&nbsp;Xinlong Wu ,&nbsp;Jiahui Liu ,&nbsp;Xiaoxin Yang","doi":"10.1016/j.clay.2025.107921","DOIUrl":"10.1016/j.clay.2025.107921","url":null,"abstract":"<div><div>Contact electrification, the charge exchange phenomenon occurring upon contact between dissimilar materials, is ubiquitous yet often underappreciated. Tribocatalysis, which harnesses this process to convert mechanical energy into chemical energy for degrading wastewater pollutants, has recently gained attention for its potential. In this study, we transformed natural kaolin into amorphous metakaolin (MK) tribocatalysts via a single-step calcination process, optimizing their performance through structural modulation. Solid-state NMR spectroscopy and degradation experiments revealed that MK-800, enriched with unsaturated Al[IV] and Al[V] sites, achieved a degradation rate constant of 0.1607 h⁻¹—64 times higher than that of raw kaolin. Density functional theory calculations confirmed that unsaturated aluminum coordination enhances electron mobility and reduces electron escape energy. We further refined tribocatalytic efficiency by optimizing parameters such as friction area, solution environment, and atmospheric conditions. Electron paramagnetic resonance spectroscopy identified positive charges (q⁺), hydroxyl radicals (<img>OH), and superoxide anions (<img>O₂⁻) as key reactive species driving pollutant degradation. This work introduces a novel, cost-effective approach to pollutant remediation and lays a theoretical foundation for advancing structural control in tribocatalysis.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107921"},"PeriodicalIF":5.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating adsorption of various heavy metal ions by the reaction products of chrysotile and lizardite-acid interface","authors":"Dingran Zhao ,&nbsp;Hongjuan Sun ,&nbsp;Tongjiang Peng ,&nbsp;Bo Liu ,&nbsp;Saeed Rehman ,&nbsp;Li Zeng","doi":"10.1016/j.clay.2025.107925","DOIUrl":"10.1016/j.clay.2025.107925","url":null,"abstract":"<div><div>With the intensification of mineral resource exploitation, processing activities, and industrial operations worldwide, local soil and water bodies are becoming more and more acidified. Under acidic conditions, the chemical reaction at the interface between serpentine minerals, which are abundant on Earth, and water becomes more complex. Particularly, in slightly acidic wastewater, multiple heavy metal ions often coexist. Therefore, it is of great significance to study the interface ion-specific adsorption behavior of different heavy metal ions by the reaction products at the serpentine-water interface. This study, selected chrysotile and lizardite with distinct structures as raw materials to investigate the variations in their structure, morphology, and associated properties in a 1 mol/L sulfuric acid solution, along with the adsorption characteristics of the reaction products for typical heavy metal ions such as Cr³⁺, Mn²⁺ and Ni²⁺. The results indicate that during the acid treatment process, serpentine minerals with different structures are subjected to varying degrees of structural damage, particularly lizardite, which suffers more severe structural damage. Additionally, the specific surface area and pore volume of the reaction products increased, especially the increase in the edge structure, which enhanced the saturated adsorption capacity for Cr³⁺, Mn²⁺ and Ni²⁺. Kinetics studies revealed that the adsorption effect of the reaction products of serpentine on Cr³⁺ was the most pronounced, indicating an obvious preferential competitive adsorption behavior. The adsorption of these heavy metal ions onto the reaction products followed pseudo-second-order kinetic models as well as Langmuir isothermal adsorption models. This suggests that their adsorption mechanism is mainly a chemical process of monolayer adsorption. Thermodynamic analysis showed that temperature had the most significant influence on the adsorption process of Cr³⁺ among the studied heavy metal ions. These findings contribute to a deeper understanding the serpentine-water interface reaction process, the self-purification effect, and its impact on Earth's surface ecosystems.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107925"},"PeriodicalIF":5.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of montmorillonite clay for its potential application for pesticides adsorption in single and binary systems","authors":"Lotfi Sellaoui ,&nbsp;Felycia Edi Soetaredjo ,&nbsp;Nour Sghaier ,&nbsp;Alessandro Erto ,&nbsp;Taoufik Saidani ,&nbsp;Norah Alwadai ,&nbsp;Michael Badawi ,&nbsp;Guilherme Luiz Dotto ,&nbsp;Suryadi Ismadji","doi":"10.1016/j.clay.2025.107922","DOIUrl":"10.1016/j.clay.2025.107922","url":null,"abstract":"<div><div>Single-compounds and binary experimental data on the adsorption of 2,4-Dichlorophenoxyacetic acid (2,4-D) and Acifluorfen (ACF) onto montmorillonite are obtained at different temperatures (30, 40, 50 °C) to explain and understand the competitive interactions between these water contaminants. The experimental results indicate that the maximum adsorption capacities of ACF in the single-compound system are approximately 90, 130, and 161 mg/g, respectively. In the binary system, these capacities decrease to 73, 114, and 142 mg/g, respectively. For 2,4-D, single-compound adsorption capacities varied from 55, 89 to 119 mg/g, while in binary system, they decreased to 44, 71 and 98 mg/g, respectively. The reduction in adsorption performance is related to the competitive effect between the investigated molecules. To further elucidate the adsorption mechanisms in single-compound and binary systems, a theoretical study based on modeling analysis is conducted. A double-layer adsorption model for single-compound and a competitive adsorption model for binary systems are employed to deeper investigate the possible mechanisms involved.</div><div>The results indicate that ACF is adsorbed via an aggregation process, forming trimers at lower temperatures (30 °C), whereas this aggregation is reduced at higher temperatures (50 °C), leading to monomer formation. In contrast, 2,4-D is removed without undergoing an aggregation process. Binary modeling revealed that the presence of a second compound in solution creates an antagonistic effect, leading to reduced adsorption capacities. This theoretical approach demonstrates that ACF and 2,4-D are adsorbed primarily through physical interactions, with endothermic processes playing a key role in their removal.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107922"},"PeriodicalIF":5.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of temperature on structure and mechanical properties of kaolinite via experiments and reactive molecular dynamics simulations","authors":"Yiming Liu,&nbsp;Yuanyuan Zheng,&nbsp;Hongjie Lin,&nbsp;Qichang Fan,&nbsp;Ting Tan","doi":"10.1016/j.clay.2025.107918","DOIUrl":"10.1016/j.clay.2025.107918","url":null,"abstract":"<div><div>To explore the temperature required for dehydroxylation of clay minerals and the properties of calcined clay in Limestone Calcined Clay Cement (LC3), this work took kaolinite as the research object. The chemical transformation of kaolinite after heat treatment was investigated by Thermogravimetric test (TG), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Fourier Transform Infrared spectrum (FT-IR). Meanwhile, the internal mechanism of structural transformation and mechanical response was investigated by Reactive Molecular Dynamics (RMD) simulations. TG, FT-IR, and XRD analysis results showed that free water was removed at 378 K, dehydroxylation of kaolinite began at 673 K, and dehydroxylation was complete at 873 K. FT-IR analysis results showed that kaolinite tetrahedron remained stable, while octahedron changed. RMD simulations results showed that dehydroxylation of kaolinite began at 378 K ∼ 473 K, and kaolinite was transformed into metakaolinite at 873 K. And the results also showed that the formation of silanol (Si-OH) caused the peak of FT-IR to widen. The internal mechanism of the interlayer structural transformation of kaolinite was revealed through the analysis of layer spacing, interlayer adhesion work, interlayer water molecules, and H-bond. Eventually, RMD simulations results showed that metakaolinite had stronger deformation resistance than kaolinite by calculating the elastic constants.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"276 ","pages":"Article 107918"},"PeriodicalIF":5.3,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}