Pub Date : 2025-12-17DOI: 10.1016/j.clay.2025.108091
Juraj Krajč , Peter Boháč , Juraj Bujdák
For the first time, the interparticle diffusion of organic dye cations in hybrid clay colloids has been investigated in detail. The phenomenon was directly proven by experiments. Distances between dye molecules were monitored by Förster resonance energy transfer (FRET), enabling a sensitive probe of diffusion dynamics. Kinetic profiles demonstrated a strong temperature dependence, while additional effects such as concentration quenching and colloidal destabilization also contributed to the observed behavior. This methodology offers a powerful new route for characterizing diffusion phenomena in hybrid clay colloids and analogous systems.
{"title":"Interparticle diffusion of dye cations in saponite dispersions monitored by fluorescence spectroscopy","authors":"Juraj Krajč , Peter Boháč , Juraj Bujdák","doi":"10.1016/j.clay.2025.108091","DOIUrl":"10.1016/j.clay.2025.108091","url":null,"abstract":"<div><div>For the first time, the interparticle diffusion of organic dye cations in hybrid clay colloids has been investigated in detail. The phenomenon was directly proven by experiments. Distances between dye molecules were monitored by Förster resonance energy transfer (FRET), enabling a sensitive probe of diffusion dynamics. Kinetic profiles demonstrated a strong temperature dependence, while additional effects such as concentration quenching and colloidal destabilization also contributed to the observed behavior. This methodology offers a powerful new route for characterizing diffusion phenomena in hybrid clay colloids and analogous systems.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"282 ","pages":"Article 108091"},"PeriodicalIF":5.8,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789204","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}
Pub Date : 2025-12-16DOI: 10.1016/j.clay.2025.108089
Ivan M. Zdretsov, Andrey M. Gerasimov
Zeolite 4A has numerous established and advanced applications. Using kaolin instead of conventional SiO2 and Al2O3 sources makes its synthesis relatively green and low-cost. The best performance requires zeolite 4A to have high purity and specific particle size and morphology. However, fine-tuning these parameters is challenging due to the many influencing factors, and kaolin as a raw material only increases their number. Here, we modeled the dependence of zeolite 4A properties (relative crystallinity, yield, water vapor capacity, average size of particles and zeolite 4A cubic crystals, average number of cubes in agglomerate) on four synthesis parameters (temperature, time, stirring speed, Na2O: Al2O3) via response surface methodology (RSM), namely the Box-Behnken design (BBD). Products were synthesized in two steps: metakaolinization and hydrothermal crystallization. We applied powder X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy with energy dispersive X-ray (SEM-EDX), differential thermal and thermogravimetric analysis (DTA-TGA), laser diffraction analysis (LDA) and other techniques to characterize the samples. As a result, we obtained response surfaces and used them to synthesize zeolite 4A with high relative crystallinity. In addition, it was found that at a high alkali content in the reaction mixture, e.g. Na2O: Al2O3 = 5, the product particles are identical in shape to precursor ones but consist of tiny zeolite crystals with an average size of 0.94–1.83 μm. We also observed several previously known crystallization mechanisms. The obtained models, observations, and experimental data expand the toolbox for producing zeolites from kaolin, and may become the basis for relatively green and low-cost technology.
{"title":"Modeling of zeolite 4A synthesis with different particle morphology from kaolin via response surface methodology","authors":"Ivan M. Zdretsov, Andrey M. Gerasimov","doi":"10.1016/j.clay.2025.108089","DOIUrl":"10.1016/j.clay.2025.108089","url":null,"abstract":"<div><div>Zeolite 4A has numerous established and advanced applications. Using kaolin instead of conventional SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> sources makes its synthesis relatively green and low-cost. The best performance requires zeolite 4A to have high purity and specific particle size and morphology. However, fine-tuning these parameters is challenging due to the many influencing factors, and kaolin as a raw material only increases their number. Here, we modeled the dependence of zeolite 4A properties (relative crystallinity, yield, water vapor capacity, average size of particles and zeolite 4A cubic crystals, average number of cubes in agglomerate) on four synthesis parameters (temperature, time, stirring speed, Na<sub>2</sub>O: Al<sub>2</sub>O<sub>3</sub>) <em>via</em> response surface methodology (RSM), namely the Box-Behnken design (BBD). Products were synthesized in two steps: metakaolinization and hydrothermal crystallization. We applied powder X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy with energy dispersive X-ray (SEM-EDX), differential thermal and thermogravimetric analysis (DTA-TGA), laser diffraction analysis (LDA) and other techniques to characterize the samples. As a result, we obtained response surfaces and used them to synthesize zeolite 4A with high relative crystallinity. In addition, it was found that at a high alkali content in the reaction mixture, <em>e.g.</em> Na<sub>2</sub>O: Al<sub>2</sub>O<sub>3</sub> = 5, the product particles are identical in shape to precursor ones but consist of tiny zeolite crystals with an average size of 0.94–1.83 μm. We also observed several previously known crystallization mechanisms. The obtained models, observations, and experimental data expand the toolbox for producing zeolites from kaolin, and may become the basis for relatively green and low-cost technology.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"282 ","pages":"Article 108089"},"PeriodicalIF":5.8,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753893","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}
Pub Date : 2025-12-15DOI: 10.1016/j.clay.2025.108090
Weihua Meng , Da Yang , Shengnan Wang , Chenyang Liu , Pengyang Zou , Yuan Li , Jixing Xie , Jianzhong Xu
Epoxy resin (EP) is a high-performance polymer whose broader application is restricted by inherent flammability. In this work, a novel core-shell ILA@ATMEL was synthesized by coating natural illite with melamine-based aminotrimethylene phosphonate (ATMEL). The resulting hybrid was incorporated into EP to simultaneously improve flame retardancy and mechanical properties. With the addition of 9 phr ILA@ATMEL, the limiting oxygen index of EP composite reached 28.8 %, and the char residue at 800 °C increased from 17.82 % to 29.57 %. Cone calorimetry tests revealed notable reductions in peak heat release rate (33.57 %), total heat release (20.89 %), peak smoke production rate (29.37 %), and total smoke production (14.17 %) compared to those of pore EP. These improvements are attributed to synergistic flame-retardant mechanisms both in the condensed phase and the gas phase with Si, Al, P, and N elements. Moreover, ILA@ATMEL acts as a reinforcing filler at low loadings. The composite with 3 phr additive exhibited increases in elongation at break and tensile strength by 10.57 % and 18.86 %, respectively. This study demonstrates a feasible strategy for designing eco-friendly, high-performance EP composites with enhanced fire safety and mechanical durability via mineral-based core-shell flame retardants.
{"title":"Synthesis of modified illite coated with melamine and aminotrimethylene phosphonic acid and study on its flame-retardant properties for epoxy resin","authors":"Weihua Meng , Da Yang , Shengnan Wang , Chenyang Liu , Pengyang Zou , Yuan Li , Jixing Xie , Jianzhong Xu","doi":"10.1016/j.clay.2025.108090","DOIUrl":"10.1016/j.clay.2025.108090","url":null,"abstract":"<div><div>Epoxy resin (EP) is a high-performance polymer whose broader application is restricted by inherent flammability. In this work, a novel core-shell ILA@ATMEL was synthesized by coating natural illite with melamine-based aminotrimethylene phosphonate (ATMEL). The resulting hybrid was incorporated into EP to simultaneously improve flame retardancy and mechanical properties. With the addition of 9 phr ILA@ATMEL, the limiting oxygen index of EP composite reached 28.8 %, and the char residue at 800 °C increased from 17.82 % to 29.57 %. Cone calorimetry tests revealed notable reductions in peak heat release rate (33.57 %), total heat release (20.89 %), peak smoke production rate (29.37 %), and total smoke production (14.17 %) compared to those of pore EP. These improvements are attributed to synergistic flame-retardant mechanisms both in the condensed phase and the gas phase with Si, Al, P, and N elements. Moreover, ILA@ATMEL acts as a reinforcing filler at low loadings. The composite with 3 phr additive exhibited increases in elongation at break and tensile strength by 10.57 % and 18.86 %, respectively. This study demonstrates a feasible strategy for designing eco-friendly, high-performance EP composites with enhanced fire safety and mechanical durability via mineral-based core-shell flame retardants.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"282 ","pages":"Article 108090"},"PeriodicalIF":5.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753892","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}
Pub Date : 2025-12-12DOI: 10.1016/j.clay.2025.108087
Denise Eulálio , Mariana Pires Figueiredo , Simone S. Silva , Luísa C. Rodrigues , Emanuel M. Fernandes , Albino Martins , Albina Franco , Diana Soares da Costa , Richard Landers , Fabrice Leroux , Christine Taviot-Gueho , Dalva Lúcia Araújo de Faria , Rui L. Reis , Vera Regina Leopoldo Constantino
Zinc ions and N-acetylcysteine (NAC) are bioactive agents with key physiological roles. When associated with biomacromolecules such as silk fibroin (SF), they offer a promising pathway for advanced biomedical applications. This study reports the synthesis of layered zinc hydroxide (LZH) intercalated with NAC as well as the development of LZH-NAC/SF scaffolds. The synthesis of LZH-NAC was conducted using a constant-pH method, and experimental parameters were controlled to obtain a monophasic LZH. Comprehensive structural, spectroscopic, textural, and thermal characterisation confirmed the successful intercalation of NAC into the LZH. The employed methodology enabled the production of an LZH-NAC nanomaterial with an encapsulation efficiency of approximately 80 % by mass and a loading capacity of around 30 %. To evaluate its biomedical potential, LZH-NAC/SF 3D composite scaffolds were prepared by dispersing LZH-NAC in SF solution, followed by freezing and freeze-drying. The average pore sizes observed in the scaffolds ranged from 75 to 87 μm, and the swelling capacity was approximately 1700 % after incubation in phosphate-buffered saline (pH 7.4). Cytocompatibility assays revealed that LZH-NAC/SF scaffolds supported cell viability at a zinc concentration of 0.189 mg/mL, similar to that of the SF and NAC/SF scaffolds. These results underscore the potential of LZH-NAC/SF scaffolds as multifunctional biomaterials for the controlled delivery of therapeutic agents, with significant implications for tissue engineering and drug delivery systems.
{"title":"Layered zinc hydroxide–dipeptide hybrid integrated into silk-based 3D scaffolds aiming for biomedical applications","authors":"Denise Eulálio , Mariana Pires Figueiredo , Simone S. Silva , Luísa C. Rodrigues , Emanuel M. Fernandes , Albino Martins , Albina Franco , Diana Soares da Costa , Richard Landers , Fabrice Leroux , Christine Taviot-Gueho , Dalva Lúcia Araújo de Faria , Rui L. Reis , Vera Regina Leopoldo Constantino","doi":"10.1016/j.clay.2025.108087","DOIUrl":"10.1016/j.clay.2025.108087","url":null,"abstract":"<div><div>Zinc ions and <em>N</em>-acetylcysteine (NAC) are bioactive agents with key physiological roles. When associated with biomacromolecules such as silk fibroin (SF), they offer a promising pathway for advanced biomedical applications. This study reports the synthesis of layered zinc hydroxide (LZH) intercalated with NAC as well as the development of LZH-NAC/SF scaffolds. The synthesis of LZH-NAC was conducted using a constant-pH method, and experimental parameters were controlled to obtain a monophasic LZH. Comprehensive structural, spectroscopic, textural, and thermal characterisation confirmed the successful intercalation of NAC into the LZH. The employed methodology enabled the production of an LZH-NAC nanomaterial with an encapsulation efficiency of approximately 80 % by mass and a loading capacity of around 30 %. To evaluate its biomedical potential, LZH-NAC/SF 3D composite scaffolds were prepared by dispersing LZH-NAC in SF solution, followed by freezing and freeze-drying. The average pore sizes observed in the scaffolds ranged from 75 to 87 μm, and the swelling capacity was approximately 1700 % after incubation in phosphate-buffered saline (pH 7.4). Cytocompatibility assays revealed that LZH-NAC/SF scaffolds supported cell viability at a zinc concentration of 0.189 mg/mL, similar to that of the SF and NAC/SF scaffolds. These results underscore the potential of LZH-NAC/SF scaffolds as multifunctional biomaterials for the controlled delivery of therapeutic agents, with significant implications for tissue engineering and drug delivery systems.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108087"},"PeriodicalIF":5.8,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734457","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}
Pub Date : 2025-12-12DOI: 10.1016/j.clay.2025.108088
Andrea Bloise , Ilaria Fuoco , Carmine Apollaro , Giovanni Vespasiano , Ekaterina Khrapova , Andrei Krasilin
Chrysotile, the fibrous form of serpentine, is characterized by the chemical formula Mg3Si2O5(OH)4. Over the past seventy years, significant research has focused on synthesizing chrysotile, initially for petrological studies and more recently for applications in nanotechnology, particularly high-purity chrysotile nanotubes and doped variants. Common synthesis methods involve hydrothermal reactions using cristobalite and periclase or magnesium hydroxide and silica gel mixtures. Most frequently used synthesis conditions generally include temperatures between 200 °C and 400 °C and pressures from 0.5 to 100 MPa, though these often result in impure chrysotile with unwanted phases. Despite the promise of doped chrysotile, natural fibers are often unsuitable for nanoscience due to foreign ions and mineral intergrowths. Recent studies explore the potential for creating isomorphic series as Mg3Si2O5(OH)4 – Ni3Si2O5(OH)4 or Mg3Si2O5(OH)4 - (Fe2+, Fe3+)3-2Si2O5(OH)4, examining the impact of nickel and iron on chrysotile's properties. This study provides a review of the reported synthesis methods for chrysotile, emphasizing the synthesis techniques, precursor materials, and the resulting crystal chemistry. The findings highlight the dynamic nature of chrysotile synthesis research, with implications for materials science, including the development of novel nanostructures and environmental remediation technologies.
{"title":"Retrospective of chrysotile synthesis: From tough geoinspired process up to soft chemical design","authors":"Andrea Bloise , Ilaria Fuoco , Carmine Apollaro , Giovanni Vespasiano , Ekaterina Khrapova , Andrei Krasilin","doi":"10.1016/j.clay.2025.108088","DOIUrl":"10.1016/j.clay.2025.108088","url":null,"abstract":"<div><div>Chrysotile, the fibrous form of serpentine, is characterized by the chemical formula Mg<sub>3</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub>. Over the past seventy years, significant research has focused on synthesizing chrysotile, initially for petrological studies and more recently for applications in nanotechnology, particularly high-purity chrysotile nanotubes and doped variants. Common synthesis methods involve hydrothermal reactions using cristobalite and periclase or magnesium hydroxide and silica gel mixtures. Most frequently used synthesis conditions generally include temperatures between 200 °C and 400 °C and pressures from 0.5 to 100 MPa, though these often result in impure chrysotile with unwanted phases. Despite the promise of doped chrysotile, natural fibers are often unsuitable for nanoscience due to foreign ions and mineral intergrowths. Recent studies explore the potential for creating isomorphic series as Mg<sub>3</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub> – Ni<sub>3</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub> or Mg<sub>3</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub> - (Fe<sup>2+</sup>, Fe<sup>3+</sup>)<sub>3-2</sub>Si<sub>2</sub>O<sub>5</sub>(OH)<sub>4</sub>, examining the impact of nickel and iron on chrysotile's properties. This study provides a review of the reported synthesis methods for chrysotile, emphasizing the synthesis techniques, precursor materials, and the resulting crystal chemistry. The findings highlight the dynamic nature of chrysotile synthesis research, with implications for materials science, including the development of novel nanostructures and environmental remediation technologies.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108088"},"PeriodicalIF":5.8,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734948","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}
Pub Date : 2025-12-10DOI: 10.1016/j.clay.2025.108086
María Victoria Villar , Andrés Idiart , Emilie Coene , Jaime Cuevas , Ana María Melón , Ana I. Ruiz , Almudena Ortega , Ville Heino
To help describing and understanding the mechanisms and factors governing the geochemical evolution and mineralogical alteration of compacted bentonite under hydraulic and thermal gradients similar to those experienced by engineered barriers in radioactive waste repositories, an experimental and modelling programme was carried out. Six thermo-hydraulic tests were performed in cylindrical cells (10 × 10 cm) using compacted Wyoming-type bentonite. The bottom of the cells was initially heated at 90 °C and once hydraulic equilibrium was reached, hydration of the bentonite started through the top surface for different periods of time (1, 2.5 and 5 years). The top surface was maintained at 20 °C during the whole test duration to induce a thermal gradient. The composition of the hydration water reproduced, for half of the cells, that of a saline groundwater and for the other half, of a dilute glacial water. The temperature of the heater was increased to 110 °C after ∼1 year of hydration. At termination, the bentonite was characterised. The thermo-hydraulic evolution during operation, final state of the bentonite and its mineralogical changes were simulated with a thermo-hydro-chemical model and reported in a companion paper.
Hydration brought about dissolution of calcite and gypsum, partial substitution of exchangeable sodium by calcium in the interlayer and transport of solutes towards hotter areas, where they precipitated as anhydrite and halite when saline water was used. In the longer term, the concentration gradient prompted the diffusive transport of chloride. The cation exchange capacity did not change over time, confirming the lack of changes in the montmorillonite crystal-chemistry that the mineralogical analyses had shown. The smectite interlayer composition kept its predominant monovalent character, although the exchangeable magnesium and potassium increased transitorily towards the heater while the bentonite remained unsaturated. The patterns observed were the same irrespective of the kind of water used, but the processes were enhanced with saline water.
{"title":"Five-year thermo-hydro-mechanical and chemical evolution of compacted bentonite: reactive transport","authors":"María Victoria Villar , Andrés Idiart , Emilie Coene , Jaime Cuevas , Ana María Melón , Ana I. Ruiz , Almudena Ortega , Ville Heino","doi":"10.1016/j.clay.2025.108086","DOIUrl":"10.1016/j.clay.2025.108086","url":null,"abstract":"<div><div>To help describing and understanding the mechanisms and factors governing the geochemical evolution and mineralogical alteration of compacted bentonite under hydraulic and thermal gradients similar to those experienced by engineered barriers in radioactive waste repositories, an experimental and modelling programme was carried out. Six thermo-hydraulic tests were performed in cylindrical cells (10 × 10 cm) using compacted Wyoming-type bentonite. The bottom of the cells was initially heated at 90 °C and once hydraulic equilibrium was reached, hydration of the bentonite started through the top surface for different periods of time (1, 2.5 and 5 years). The top surface was maintained at 20 °C during the whole test duration to induce a thermal gradient. The composition of the hydration water reproduced, for half of the cells, that of a saline groundwater and for the other half, of a dilute glacial water. The temperature of the heater was increased to 110 °C after ∼1 year of hydration. At termination, the bentonite was characterised. The thermo-hydraulic evolution during operation, final state of the bentonite and its mineralogical changes were simulated with a thermo-hydro-chemical model and reported in a companion paper.</div><div>Hydration brought about dissolution of calcite and gypsum, partial substitution of exchangeable sodium by calcium in the interlayer and transport of solutes towards hotter areas, where they precipitated as anhydrite and halite when saline water was used. In the longer term, the concentration gradient prompted the diffusive transport of chloride. The cation exchange capacity did not change over time, confirming the lack of changes in the montmorillonite crystal-chemistry that the mineralogical analyses had shown. The smectite interlayer composition kept its predominant monovalent character, although the exchangeable magnesium and potassium increased transitorily towards the heater while the bentonite remained unsaturated. The patterns observed were the same irrespective of the kind of water used, but the processes were enhanced with saline water.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108086"},"PeriodicalIF":5.8,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734429","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}
Pub Date : 2025-12-06DOI: 10.1016/j.clay.2025.108085
Erdi Avci , Elif Sidimi , Nana Asaam , Aysu Dag , Atiye Tugrul , Priyadharshini Perumal
This study investigates the potential of thermally activated quarry waste as alternative supplementary cementitious materials (SCMs) for sustainable binder systems. Three clay-rich materials were collected from a sand quarry located on the European side of Istanbul: two natural overburden clays (Yellow Layer-YL and Blue Layer-BL) and one process-derived sludge waste (TA) generated during sand washing. All samples were sieved (<150 μm), dried, and calcined at 800 °C for 2 h. Mineralogical (XRD), chemical (XRF), and thermal (TG, FTIR) analyses were conducted to evaluate phase transformation and amorphous phase development. Pozzolanic reactivity was assessed by the R3 test, including heat release and bound water measurements. Results showed that the TA sample exhibited the highest reactivity due to its kaolinite content and fine, homogeneous particle structure. In contrast, the BL sample demonstrated limited reactivity owing to the dominance of thermally stable phases such as muscovite and albite. Mortar specimens prepared with 20 % SCM replacement were tested for compressive strength at 7, 14, and 28 days using both CEM I and CEM II binders. The TA-C mixture achieved a compressive strength index (CSI) of 102.9 % with CEM I at 14 days, indicating strong early-age performance, while YL-C showed the highest 28-day strength with CEM II (CSI = 97.9 %). These findings confirm that sludge-based SCMs, when properly activated, can match or even exceed the performance of conventional systems, offering a viable strategy for resource-efficient and low-carbon cementitious materials.
{"title":"Quarry waste clays as supplementary cementitious materials: Mineralogical evolution and pozzolanic performance after thermal activation","authors":"Erdi Avci , Elif Sidimi , Nana Asaam , Aysu Dag , Atiye Tugrul , Priyadharshini Perumal","doi":"10.1016/j.clay.2025.108085","DOIUrl":"10.1016/j.clay.2025.108085","url":null,"abstract":"<div><div>This study investigates the potential of thermally activated quarry waste as alternative supplementary cementitious materials (SCMs) for sustainable binder systems. Three clay-rich materials were collected from a sand quarry located on the European side of Istanbul: two natural overburden clays (Yellow Layer-YL and Blue Layer-BL) and one process-derived sludge waste (TA) generated during sand washing. All samples were sieved (<150 μm), dried, and calcined at 800 °C for 2 h. Mineralogical (XRD), chemical (XRF), and thermal (TG, FTIR) analyses were conducted to evaluate phase transformation and amorphous phase development. Pozzolanic reactivity was assessed by the R<sup>3</sup> test, including heat release and bound water measurements. Results showed that the TA sample exhibited the highest reactivity due to its kaolinite content and fine, homogeneous particle structure. In contrast, the BL sample demonstrated limited reactivity owing to the dominance of thermally stable phases such as muscovite and albite. Mortar specimens prepared with 20 % SCM replacement were tested for compressive strength at 7, 14, and 28 days using both CEM I and CEM II binders. The TA-C mixture achieved a compressive strength index (CSI) of 102.9 % with CEM I at 14 days, indicating strong early-age performance, while YL-C showed the highest 28-day strength with CEM II (CSI = 97.9 %). These findings confirm that sludge-based SCMs, when properly activated, can match or even exceed the performance of conventional systems, offering a viable strategy for resource-efficient and low-carbon cementitious materials.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108085"},"PeriodicalIF":5.8,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683964","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}
Pub Date : 2025-12-05DOI: 10.1016/j.clay.2025.108066
Guixiang Teng , Hui Yao , Hongyu Wang , Shuting Zhang , Yanzan Meng , Meng Zhao , Yan Yang , Chun Zhang
To mitigate the detrimental effects of root rot disease on Chinese herbal medicines, this study developed an environmentally friendly sustained-release antimicrobial system (CEO@HNTs-NH2) based on clove essential oil (CEO) loaded onto amino-functionalized Halloysite nanotubes (HNTs-NH2). Characterization results revealed that CEO@HNTs-NH2 enhanced the thermal stability of CEO and significantly strengthened their interaction. Density Functional Theory (DFT) calculations demonstrated negative values for both the adsorption energy (−0.5772 eV) and interaction energy (−0.2117 eV) of CEO@HNTs-NH2, providing molecular-level insights into the sustained-release mechanism. The release studies demonstrated a significantly low cumulative release of 21.20 ± 0.43 % over 10 days, exhibiting Fickian diffusion kinetics (R2 = 0.99). This controlled release profile effectively mitigates the inherent volatility of CEO. Innovatively, we fabricated HAK clay tablets by compounding CEO@HNTs-NH2 with Attapulgite and Kaolin—serving as structural supporter and coating agent, respectively—at an optimal 3:2:2 ratio. The tablet formulation conditions were optimized by Box-Behnken Design, yielding the optimal parameters: molding temperature of 30 °C, pressure of 0.86 MPa, and holding time of 32 min. Finally, the pot experiments demonstrated that HAK tablets significantly reduced the plant disease severity of Rehmannia by 59.8 % (Prevention group) and 32.2 % (Treatment group) compared to the Pathogenic group, confirming their potentially antimicrobial efficacy. In summary, this clay mineral nanocomposite system achieves controlled release through synergistic physico-chemical interactions, offering an innovative strategy for the application of clay minerals in sustainable agriculture.
{"title":"Essential oil-loaded amine-modified HNTs composites for sustained release and enhanced antibacterial performance in root rot control","authors":"Guixiang Teng , Hui Yao , Hongyu Wang , Shuting Zhang , Yanzan Meng , Meng Zhao , Yan Yang , Chun Zhang","doi":"10.1016/j.clay.2025.108066","DOIUrl":"10.1016/j.clay.2025.108066","url":null,"abstract":"<div><div>To mitigate the detrimental effects of root rot disease on Chinese herbal medicines, this study developed an environmentally friendly sustained-release antimicrobial system (CEO@HNTs-NH<sub>2</sub>) based on clove essential oil (CEO) loaded onto amino-functionalized Halloysite nanotubes (HNTs-NH<sub>2</sub>). Characterization results revealed that CEO@HNTs-NH<sub>2</sub> enhanced the thermal stability of CEO and significantly strengthened their interaction. Density Functional Theory (DFT) calculations demonstrated negative values for both the adsorption energy (−0.5772 eV) and interaction energy (−0.2117 eV) of CEO@HNTs-NH<sub>2</sub>, providing molecular-level insights into the sustained-release mechanism. The release studies demonstrated a significantly low cumulative release of 21.20 ± 0.43 % over 10 days, exhibiting Fickian diffusion kinetics (R<sup>2</sup> = 0.99). This controlled release profile effectively mitigates the inherent volatility of CEO. Innovatively, we fabricated HAK clay tablets by compounding CEO@HNTs-NH<sub>2</sub> with Attapulgite and Kaolin—serving as structural supporter and coating agent, respectively—at an optimal 3:2:2 ratio. The tablet formulation conditions were optimized by Box-Behnken Design, yielding the optimal parameters: molding temperature of 30 °C, pressure of 0.86 MPa, and holding time of 32 min. Finally, the pot experiments demonstrated that HAK tablets significantly reduced the plant disease severity of <em>Rehmannia</em> by 59.8 % (Prevention group) and 32.2 % (Treatment group) compared to the Pathogenic group, confirming their potentially antimicrobial efficacy. In summary, this clay mineral nanocomposite system achieves controlled release through synergistic physico-chemical interactions, offering an innovative strategy for the application of clay minerals in sustainable agriculture.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108066"},"PeriodicalIF":5.8,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683966","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}
Pub Date : 2025-12-05DOI: 10.1016/j.clay.2025.108084
Carlos Mota-Heredia, Jaime Cuevas, Raúl Fernández
Carbon steel and bentonite are chosen as engineered barriers for high-level radioactive waste containment in deep geological repositories, which requires an evaluation of their long-term interactions to ensure durability. Two laboratory experiments were conducted under hydrothermal gradients with steel-Ca-Mg-Na-bentonite and Na-bentonite unsaturated columns over 25 and 27 months, respectively. The experiments measured changes in the porewater distribution, the specific surface area, the cation exchange capacity of the bentonites, and the oxidation state of Fe. These were determined in different sections along the columns. Mineralogical analyses were performed using X-ray diffraction and scanning electron microscopy. The results obtained showed water saturation at the conclusion of the experimental time. The specific surface area of bentonites decreased near the steel interface, while the cation exchange capacity exhibited an overall increase. The corrosion rate decreased over time, with bentonite showing enriched Fe content within the first 3.5 mm from the steel interface. New Fe-bearing minerals, including ferri-chlorite, magnetite, hematite, maghemite, and siderite, were identified as reaction products at the steel-bentonite interface. Aqueous species are redistributed in the bentonite's porewater, increasing with time the concentrations of Na+, Ca2+, Mg2+ and SO42− and decreasing those of Fe, due to the imposed hydraulic gradient and the precipitation reactions. This study compares the evolution of these bentonite properties with a previous study at short experimental times of 1 and 6 months of reaction. These findings are relevant to deep geological disposal conditions, where bentonite influences the formation and nature of iron clay minerals over time.
{"title":"Evolution of steel-bentonite interactions under hydrothermal gradients: Mineralogical and geochemical implications for nuclear waste disposal","authors":"Carlos Mota-Heredia, Jaime Cuevas, Raúl Fernández","doi":"10.1016/j.clay.2025.108084","DOIUrl":"10.1016/j.clay.2025.108084","url":null,"abstract":"<div><div>Carbon steel and bentonite are chosen as engineered barriers for high-level radioactive waste containment in deep geological repositories, which requires an evaluation of their long-term interactions to ensure durability. Two laboratory experiments were conducted under hydrothermal gradients with steel-Ca-Mg-Na-bentonite and Na-bentonite unsaturated columns over 25 and 27 months, respectively. The experiments measured changes in the porewater distribution, the specific surface area, the cation exchange capacity of the bentonites, and the oxidation state of Fe. These were determined in different sections along the columns. Mineralogical analyses were performed using X-ray diffraction and scanning electron microscopy. The results obtained showed water saturation at the conclusion of the experimental time. The specific surface area of bentonites decreased near the steel interface, while the cation exchange capacity exhibited an overall increase. The corrosion rate decreased over time, with bentonite showing enriched Fe content within the first 3.5 mm from the steel interface. New Fe-bearing minerals, including ferri-chlorite, magnetite, hematite, maghemite, and siderite, were identified as reaction products at the steel-bentonite interface. Aqueous species are redistributed in the bentonite's porewater, increasing with time the concentrations of Na<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup> and SO<sub>4</sub><sup>2−</sup> and decreasing those of Fe, due to the imposed hydraulic gradient and the precipitation reactions. This study compares the evolution of these bentonite properties with a previous study at short experimental times of 1 and 6 months of reaction. These findings are relevant to deep geological disposal conditions, where bentonite influences the formation and nature of iron clay minerals over time.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108084"},"PeriodicalIF":5.8,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683965","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}
A mock-up test on decimetric scale in an innovative column test device and small-scale element tests were carried out on a German Ca/Mg bentonite, which is investigated as a suitable material for engineered barrier systems in nuclear waste disposal. Key hydro-mechanical parameters such as relative humidity, water content and swelling pressure were monitored and spatially resolved over the 30 cm height of the column in the mock-up test. The test was hydrated from the bottom and ran for 370 days. To compare the material behaviour at different scales, swelling pressure tests and water retention measurements were performed at the element-test scale. The results of the column test showed a heterogeneous evolution of swelling pressure and hydration state variables along the column height. Simultaneous measurement of vertical and radial swelling pressure indicated swelling anisotropy. Transient measurement of relative humidity and water content revealed a redistribution of porosity within the sample, which was confirmed by sampling after completion of the test. Comparison with the results of the element test showed that the two test scales are comparable in similar hydraulic states. The column test is therefore suitable as a precursor to the field test and provides valuable insights into the spatially and temporally resolved hydration behaviour of a buffer material, which helps for the design of in-situ experiments, the validation of numerical models and supports the overall process understanding.
{"title":"Swelling behaviour of compacted Ca/Mg bentonite during hydration on different scales","authors":"Antonia Nitsch , Ali Asaad , Torsten Wichtmann , Katja Emmerich , Wiebke Baille","doi":"10.1016/j.clay.2025.108067","DOIUrl":"10.1016/j.clay.2025.108067","url":null,"abstract":"<div><div>A mock-up test on decimetric scale in an innovative column test device and small-scale element tests were carried out on a German Ca/Mg bentonite, which is investigated as a suitable material for engineered barrier systems in nuclear waste disposal. Key hydro-mechanical parameters such as relative humidity, water content and swelling pressure were monitored and spatially resolved over the 30 cm height of the column in the mock-up test. The test was hydrated from the bottom and ran for 370 days. To compare the material behaviour at different scales, swelling pressure tests and water retention measurements were performed at the element-test scale. The results of the column test showed a heterogeneous evolution of swelling pressure and hydration state variables along the column height. Simultaneous measurement of vertical and radial swelling pressure indicated swelling anisotropy. Transient measurement of relative humidity and water content revealed a redistribution of porosity within the sample, which was confirmed by sampling after completion of the test. Comparison with the results of the element test showed that the two test scales are comparable in similar hydraulic states. The column test is therefore suitable as a precursor to the field test and provides valuable insights into the spatially and temporally resolved hydration behaviour of a buffer material, which helps for the design of in-situ experiments, the validation of numerical models and supports the overall process understanding.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"281 ","pages":"Article 108067"},"PeriodicalIF":5.8,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683963","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}
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