The insufficient soluble silicon and heavy metal contamination in soil severely threaten the yield and quality of crops, which urgently requires dual-functional materials to address the above issues. Herein, a high-performance hierarchical magnesium silicate/diatomite (Si/Mg/xK) composite is synthesized via a one-step hydrothermal method. Natural diatomite serves as both a porous support and silicon source, while cost-effective magnesium sulfate concentrate derived from flue gas desulfurization (FGD) waste provides the magnesium source and weak alkalinity condition. Potassium hydroxide is introduced as an alkaline activator to accelerate the in-situ formation of magnesium silicate nanostructure on diatomite, creating hierarchical porosity that significantly enhances the specific surface area and increases the interaction interface with target solutions. The resulting composite achieves a remarkable citrate-soluble silicon content of 391.89 mg/L, representing a 39-fold improvement over raw diatomite, while concurrently releasing beneficial soluble magnesium (253.33 mg/L). Furthermore, the composite demonstrates exceptional heavy metal ion adsorption performance with a maximum cadmium ion (Cd2+) adsorption capacity of 184.5 mg/L, indicating dual-functional potential for soil remediation. This work establishes a sustainable pathway to valorize natural diatomite and FGD waste into dual-functional materials capable of efficient silicon/magnesium release and Cd2+ adsorption.
{"title":"Waste-derived dual-functional hierarchical magnesium silicate/diatomite composite for efficient silicon release and cadmium adsorption","authors":"Qinqin Zhou, Xiaoshuai Ma, Shaokang Hu, Siyu Hao, Yutong Rao, Chuanjin Wang, Qingyan Bai, Peng Hu, Wei Liu, Jinshu Wang","doi":"10.1016/j.clay.2026.108158","DOIUrl":"10.1016/j.clay.2026.108158","url":null,"abstract":"<div><div>The insufficient soluble silicon and heavy metal contamination in soil severely threaten the yield and quality of crops, which urgently requires dual-functional materials to address the above issues. Herein, a high-performance hierarchical magnesium silicate/diatomite (Si/Mg/<em>x</em>K) composite is synthesized via a one-step hydrothermal method. Natural diatomite serves as both a porous support and silicon source, while cost-effective magnesium sulfate concentrate derived from flue gas desulfurization (FGD) waste provides the magnesium source and weak alkalinity condition. Potassium hydroxide is introduced as an alkaline activator to accelerate the in-situ formation of magnesium silicate nanostructure on diatomite, creating hierarchical porosity that significantly enhances the specific surface area and increases the interaction interface with target solutions. The resulting composite achieves a remarkable citrate-soluble silicon content of 391.89 mg/L, representing a 39-fold improvement over raw diatomite, while concurrently releasing beneficial soluble magnesium (253.33 mg/L). Furthermore, the composite demonstrates exceptional heavy metal ion adsorption performance with a maximum cadmium ion (Cd<sup>2+</sup>) adsorption capacity of 184.5 mg/L, indicating dual-functional potential for soil remediation. This work establishes a sustainable pathway to valorize natural diatomite and FGD waste into dual-functional materials capable of efficient silicon/magnesium release and Cd<sup>2+</sup> adsorption.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"285 ","pages":"Article 108158"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171408","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 : 2026-06-01Epub Date: 2026-02-01DOI: 10.1016/j.clay.2026.108144
Angelo Oliveira Silva , Marco D'Agostini , Dachamir Hotza , Paolo Colombo
This study investigates the development and characterization of 3D printed potassium-based geopolymers reinforced with chitosan, aiming to enhance material properties for environmental applications. The addition of chitosan improved the microstructure, pore morphology, dimensional accuracy, and rheological properties of the printed samples. X-ray diffraction (XRD) analysis confirmed successful geopolymerization across all chitosan concentrations, with shifts in the amorphous halo indicating structural transformation. Scanning electron microscopy (SEM) revealed fewer cracks and unreacted particles, leading to a dense, homogeneous matrix. Pore morphology analysis, using nitrogen physisorption, showed that the low-water (LW) system had a higher specific surface area (up to 111 m2/g) and more monodisperse mesopores, while the high-water (HW) system exhibited broader pore distributions and macroporosity. Dimensional accuracy analysis revealed deviations, with LW formulations maintaining better geometric precision. Chitosan improved the height-to-width ratios in the manufactured samples, enhancing printability. Rheological tests, including flow curves and amplitude sweeps, confirmed shear-thinning behavior and significant thixotropic recovery for the feedstock, ensuring shape retention and dimensional stability in 3D printing. These findings highlight the potential of chitosan-enhanced potassium-based geopolymers for environmental applications, especially in adsorption processes, by combining tunable porosity, high surface area, and improved printability for sustainable material solutions.
{"title":"Novel extruded 3D printed potassium geopolymer composites containing chitosan","authors":"Angelo Oliveira Silva , Marco D'Agostini , Dachamir Hotza , Paolo Colombo","doi":"10.1016/j.clay.2026.108144","DOIUrl":"10.1016/j.clay.2026.108144","url":null,"abstract":"<div><div>This study investigates the development and characterization of 3D printed potassium-based geopolymers reinforced with chitosan, aiming to enhance material properties for environmental applications. The addition of chitosan improved the microstructure, pore morphology, dimensional accuracy, and rheological properties of the printed samples. X-ray diffraction (XRD) analysis confirmed successful geopolymerization across all chitosan concentrations, with shifts in the amorphous halo indicating structural transformation. Scanning electron microscopy (SEM) revealed fewer cracks and unreacted particles, leading to a dense, homogeneous matrix. Pore morphology analysis, using nitrogen physisorption, showed that the low-water (LW) system had a higher specific surface area (up to 111 m<sup>2</sup>/g) and more monodisperse mesopores, while the high-water (HW) system exhibited broader pore distributions and macroporosity. Dimensional accuracy analysis revealed deviations, with LW formulations maintaining better geometric precision. Chitosan improved the height-to-width ratios in the manufactured samples, enhancing printability. Rheological tests, including flow curves and amplitude sweeps, confirmed shear-thinning behavior and significant thixotropic recovery for the feedstock, ensuring shape retention and dimensional stability in 3D printing. These findings highlight the potential of chitosan-enhanced potassium-based geopolymers for environmental applications, especially in adsorption processes, by combining tunable porosity, high surface area, and improved printability for sustainable material solutions.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"285 ","pages":"Article 108144"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090768","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 : 2026-06-01Epub Date: 2026-02-07DOI: 10.1016/j.clay.2026.108156
Jun REN , Wei YAN , Serina Ng , Yu JIN
This study presents a novel approach combining ultrasonic treatment and flash calcination to enhance the pozzolanic reactivity of engineering spoil with low clay mineral content. To elucidate the underlying mechanisms, the treatment was applied to both the spoil and its three constituent clays: kaolinite, montmorillonite, and muscovite. A thorough characterization of the spoil revealed that ultrasonic treatment resulted in a median reduction in particle size of 36%. Subsequent flash calcination resulted in the generation of reactive Al(V) species, as confirmed by 27Al magic-angle spinning nuclear magnetic resonance (MAS-NMR). The combined treatment resulted in a 22% increase in the 48-h cumulative heat release, as measured by R3 calorimetry. A significantly more pronounced enhancement of 43% was observed for kaolinite, while the response of montmorillonite and muscovite was comparatively limited. The study on the constituent minerals of the spoil indicated that the synergistic effect is attributed to delamination of clay aggregate, which in turn leads to an increase in amorphization degree. These findings demonstrate a promising pathway for transforming engineering spoil into high-value supplementary cementitious materials.
{"title":"Synergistic ultrasonic–flash calcination to enhance pozzolanic reactivity of engineering spoil","authors":"Jun REN , Wei YAN , Serina Ng , Yu JIN","doi":"10.1016/j.clay.2026.108156","DOIUrl":"10.1016/j.clay.2026.108156","url":null,"abstract":"<div><div>This study presents a novel approach combining ultrasonic treatment and flash calcination to enhance the pozzolanic reactivity of engineering spoil with low clay mineral content. To elucidate the underlying mechanisms, the treatment was applied to both the spoil and its three constituent clays: kaolinite, montmorillonite, and muscovite. A thorough characterization of the spoil revealed that ultrasonic treatment resulted in a median reduction in particle size of 36%. Subsequent flash calcination resulted in the generation of reactive Al(V) species, as confirmed by <sup>27</sup>Al magic-angle spinning nuclear magnetic resonance (MAS-NMR). The combined treatment resulted in a 22% increase in the 48-h cumulative heat release, as measured by R<sup>3</sup> calorimetry. A significantly more pronounced enhancement of 43% was observed for kaolinite, while the response of montmorillonite and muscovite was comparatively limited. The study on the constituent minerals of the spoil indicated that the synergistic effect is attributed to delamination of clay aggregate, which in turn leads to an increase in amorphization degree. These findings demonstrate a promising pathway for transforming engineering spoil into high-value supplementary cementitious materials.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"285 ","pages":"Article 108156"},"PeriodicalIF":5.8,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171410","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 : 2026-05-01Epub Date: 2026-01-20DOI: 10.1016/j.clay.2026.108131
Andreas Jenni , Thomas Gimmi , Johannes C.L. Meeussen , Mirjam Kiczka , Urs Mäder
Within the Swiss deep drilling campaign 2019–2022, a series of Jurassic (Dogger, Lias) claystone samples were mineralogically and geochemically characterised and used in small-scale transport experiments. The advective-diffusive transport experiments clearly showed a faster breakthrough of anions relative to neutral tracers, which agrees with the accumulation of anions in a relatively faster moving porewater fraction due to anion repulsion by negatively charged clay surfaces. Electroneutral tracers were not affected by the clay charge and thus evenly distributed in all porewater domains, including stationary ones, and were transported more slowly than anions. The experiments showed consistently a faster breakthrough of Br relative to Cl, which was intuitively not expected based on the equal charge and chemical behaviour of these ions. Simulations with a continuum finite volume model approach that considers electrostatic effects in clay accurately described the different breakthrough curves of charged and neutral tracers. Matching of breakthrough behaviour required a model explicitly considering heterogeneous flow, because the simple Fickian advection-dispersion equation failed to predict the experimental data of all tracers in a consistent way. The model indicated that although the exclusion behaviour of Cl and Br as a function of concentration and surface potential is the same, the effective retardation factor (and thus breakthrough) of each ion depends on the difference in concentration of initial in-situ porewater and that of the infiltrating solution. Heterogeneous flow, electrostatic interactions, and multicomponent transport are key processes governing solute transport in claystone cores under large hydraulic gradients. These mechanisms were therefore incorporated into the presented model, enabling successful simulation of the experimental data.
{"title":"Tracer transport in claystones at the core scale: Experiments and modelling","authors":"Andreas Jenni , Thomas Gimmi , Johannes C.L. Meeussen , Mirjam Kiczka , Urs Mäder","doi":"10.1016/j.clay.2026.108131","DOIUrl":"10.1016/j.clay.2026.108131","url":null,"abstract":"<div><div>Within the Swiss deep drilling campaign 2019–2022, a series of Jurassic (Dogger, Lias) claystone samples were mineralogically and geochemically characterised and used in small-scale transport experiments. The advective-diffusive transport experiments clearly showed a faster breakthrough of anions relative to neutral tracers, which agrees with the accumulation of anions in a relatively faster moving porewater fraction due to anion repulsion by negatively charged clay surfaces. Electroneutral tracers were not affected by the clay charge and thus evenly distributed in all porewater domains, including stationary ones, and were transported more slowly than anions. The experiments showed consistently a faster breakthrough of Br relative to Cl, which was intuitively not expected based on the equal charge and chemical behaviour of these ions. Simulations with a continuum finite volume model approach that considers electrostatic effects in clay accurately described the different breakthrough curves of charged and neutral tracers. Matching of breakthrough behaviour required a model explicitly considering heterogeneous flow, because the simple Fickian advection-dispersion equation failed to predict the experimental data of all tracers in a consistent way. The model indicated that although the exclusion behaviour of Cl and Br as a function of concentration and surface potential is the same, the effective retardation factor (and thus breakthrough) of each ion depends on the difference in concentration of initial in-situ porewater and that of the infiltrating solution. Heterogeneous flow, electrostatic interactions, and multicomponent transport are key processes governing solute transport in claystone cores under large hydraulic gradients. These mechanisms were therefore incorporated into the presented model, enabling successful simulation of the experimental data.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108131"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025204","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}
The influence of textural, chemical, and swelling properties of bentonite toward trimethoprim (TMP) and chlorphenamine (CPA) adsorption was investigated. Samples of bentonite and bentonite saturated with different uptakes of these pharmaceuticals were characterized by N2 physisorption, Zeta potential, SEM, and XRD, and the uptake of cations exchanged was assessed. TMP and CPA were adsorbed within bentonite mesopores, causing pore blockage. Adsorption modified the surface charge, making it less negative as TMP and CPA uptake increased. XRD patterns showed that the d001-value expanded from 1.50 to 1.70 nm as TMP uptake increased, while no significant shift was observed for CPA. These values were consistent with the molecular sizes of both compounds, suggesting intercalation within the interlayer space of bentonite in different orientations. Cation exchange occurred with an approximate 1:1 ratio of cations exchanged. Adsorption capacities were strongly influenced by pH. Maximum uptake adsorbed was attained at pH 5 for TMP (186.6 mg/g) and pH 9 for CPA (159.8 mg/g), diminishing at higher pH. Ionic strength emphasized the role of electrostatic attractions in the adsorption mechanisms, while solution temperature had negligible effects. Reversibility studies revealed that adsorption was governed by physical and chemical interactions and demonstrated that bentonite could be reused for at least 5 cycles with adsorption percentages remaining above 85%. Experiments in wastewater treatment plant effluent confirmed effective adsorption under realistic conditions, with TMP removal being limited by speciation at pH > 7.16 and CPA efficiently adsorbed, also improving general water quality parameters.
{"title":"Impact of chemical, textural and swelling properties of bentonite on the adsorption of trimethoprim and chlorphenamine from water","authors":"Uziel Ortiz-Ramos , Roberto Leyva-Ramos , Esmeralda Mendoza-Mendoza , Francisco Carrasco-Marin , Génesis Derith Valdez-García , Antonio Aragon-Piña , Carolina Vazquez-Mendoza","doi":"10.1016/j.clay.2026.108143","DOIUrl":"10.1016/j.clay.2026.108143","url":null,"abstract":"<div><div>The influence of textural, chemical, and swelling properties of bentonite toward trimethoprim (TMP) and chlorphenamine (CPA) adsorption was investigated. Samples of bentonite and bentonite saturated with different uptakes of these pharmaceuticals were characterized by N<sub>2</sub> physisorption, Zeta potential, SEM, and XRD, and the uptake of cations exchanged was assessed. TMP and CPA were adsorbed within bentonite mesopores, causing pore blockage. Adsorption modified the surface charge, making it less negative as TMP and CPA uptake increased. XRD patterns showed that the <em>d</em><sub>001</sub>-value expanded from 1.50 to 1.70 nm as TMP uptake increased, while no significant shift was observed for CPA. These values were consistent with the molecular sizes of both compounds, suggesting intercalation within the interlayer space of bentonite in different orientations. Cation exchange occurred with an approximate 1:1 ratio of cations exchanged. Adsorption capacities were strongly influenced by <em>pH</em>. Maximum uptake adsorbed was attained at <em>pH</em> 5 for TMP (186.6 mg/g) and <em>pH</em> 9 for CPA (159.8 mg/g), diminishing at higher <em>pH</em>. Ionic strength emphasized the role of electrostatic attractions in the adsorption mechanisms, while solution temperature had negligible effects. Reversibility studies revealed that adsorption was governed by physical and chemical interactions and demonstrated that bentonite could be reused for at least 5 cycles with adsorption percentages remaining above 85%. Experiments in wastewater treatment plant effluent confirmed effective adsorption under realistic conditions, with TMP removal being limited by speciation at <em>pH</em> > 7.16 and CPA efficiently adsorbed, also improving general water quality parameters.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108143"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075298","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 : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.clay.2026.108133
Heqiu Chen , Yinze Yang , Wenya Wei , Giuseppe Cavallaro , Zhuhe Zhai , Yafei Zhao , Dan Wang , Shengqiang Chen , Huishan Shang , Bing Zhang
Exploiting inexpensive and highly porous materials for phase change materials (PCMs) encapsulation is identified as a promising strategy for addressing the shape collapse and leakage of organic PCMs. Herein, a hierarchical porous foamed geopolymer (MH) was prepared by alkali activation of meta-halloysite (MHNT) with hollow glass spheres as templates, which was then modified by polydimethylsiloxane (PDMS) to obtain superhydrophobic MH (PMH). The PMH demonstrates excellent encapsulation efficiency of 67.23% for paraffin wax (PW), exceeding that of MH (57.74%) and most reported geopolymers. The reason is attributable to the highly porous structure and superhydrophobic feature of PMH, which provides enough space for PW encapsulation and enhances the affinity between PW and PMH, respectively. Additionally, PW@PMH reveals remarkable thermal cycling stability, good thermal storage and thermal insulation performance. This work proposes a creative strategy to prepare highly porous geopolymer for PCMs encapsulation for application in thermal energy storage and thermal insulation fields.
{"title":"Superhydrophobic halloysite-based porous foamed geopolymer for efficient phase change material encapsulation with enhanced thermal management performance","authors":"Heqiu Chen , Yinze Yang , Wenya Wei , Giuseppe Cavallaro , Zhuhe Zhai , Yafei Zhao , Dan Wang , Shengqiang Chen , Huishan Shang , Bing Zhang","doi":"10.1016/j.clay.2026.108133","DOIUrl":"10.1016/j.clay.2026.108133","url":null,"abstract":"<div><div>Exploiting inexpensive and highly porous materials for phase change materials (PCMs) encapsulation is identified as a promising strategy for addressing the shape collapse and leakage of organic PCMs. Herein, a hierarchical porous foamed geopolymer (MH) was prepared by alkali activation of meta-halloysite (MHNT) with hollow glass spheres as templates, which was then modified by polydimethylsiloxane (PDMS) to obtain superhydrophobic MH (PMH). The PMH demonstrates excellent encapsulation efficiency of 67.23% for paraffin wax (PW), exceeding that of MH (57.74%) and most reported geopolymers. The reason is attributable to the highly porous structure and superhydrophobic feature of PMH, which provides enough space for PW encapsulation and enhances the affinity between PW and PMH, respectively. Additionally, PW@PMH reveals remarkable thermal cycling stability, good thermal storage and thermal insulation performance. This work proposes a creative strategy to prepare highly porous geopolymer for PCMs encapsulation for application in thermal energy storage and thermal insulation fields.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108133"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025208","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 : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.clay.2026.108134
Lukas M. Keller , Ali Seiphoori , Paul Marschall , Silvio Giger
This study examines permeability reduction in fractured Opalinus Clay material due to swelling-induced self-sealing mechanisms under controlled triaxial state conditions. An artificial continuous fracture, oriented parallel to natural fractures, was introduced to simulate an extreme scenario. Inert particle tracking was used to quantify material displacement during swelling, allowing derivation of swelling factors, porosity, and density changes. These parameters were applied to calculate spatially resolved permeability, including a swelling-induced micro-fractured damage zone modeled using a fractal scaling approach. Micro-fracture apertures ranged from pore size at the swollen region boundary up to ∼300 nm at the fracture surface. Application to 3D X-ray Computed Tomography derived fracture geometries predicted permeability reduction from ∼1 × 10−11 m2 (open) to ∼5 × 10−17 m2 (swollen), consistent with experimental results. Achieving this reduction required a swollen volume approximately seven times greater than the initial fracture volume. With continued swelling, micro-fracture apertures may shrink to ∼80 nm, further reducing bulk permeability to ∼1 × 10−18 m2, only slightly higher than that of intact material.
{"title":"Swelling-induced fracture closure in Opalinus Clay: An inert particle tracking approach","authors":"Lukas M. Keller , Ali Seiphoori , Paul Marschall , Silvio Giger","doi":"10.1016/j.clay.2026.108134","DOIUrl":"10.1016/j.clay.2026.108134","url":null,"abstract":"<div><div>This study examines permeability reduction in fractured Opalinus Clay material due to swelling-induced self-sealing mechanisms under controlled triaxial state conditions. An artificial continuous fracture, oriented parallel to natural fractures, was introduced to simulate an extreme scenario. Inert particle tracking was used to quantify material displacement during swelling, allowing derivation of swelling factors, porosity, and density changes. These parameters were applied to calculate spatially resolved permeability, including a swelling-induced micro-fractured damage zone modeled using a fractal scaling approach. Micro-fracture apertures ranged from pore size at the swollen region boundary up to ∼300 nm at the fracture surface. Application to 3D X-ray Computed Tomography derived fracture geometries predicted permeability reduction from ∼1 × 10<sup>−11</sup> m<sup>2</sup> (open) to ∼5 × 10<sup>−17</sup> m<sup>2</sup> (swollen), consistent with experimental results. Achieving this reduction required a swollen volume approximately seven times greater than the initial fracture volume. With continued swelling, micro-fracture apertures may shrink to ∼80 nm, further reducing bulk permeability to ∼1 × 10<sup>−18</sup> m<sup>2</sup>, only slightly higher than that of intact material.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108134"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025143","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 : 2026-05-01Epub Date: 2026-01-24DOI: 10.1016/j.clay.2026.108142
Alexander Pérez de la Luz , Alfredo Jiménez-Mondragón , Miriam Soriano-Santiago , Julio C. Alva-Ensastegui , Ana María Soto-Estrada , José Luis Ortiz-Quiñonez , Linda Campos-Fernández , Carolina Barrientos-Salcedo , Víctor Hugo Lara-Corona , Edtson E. Herrera-Valencia , Catalina Soriano-Correa , C. Ignacio Sainz-Díaz
American trypanosomiasis or Chagas disease, caused by Trypanosoma cruzi, remains a therapeutic challenge worldwide. Benznidazole (BNZ) and Nifurtimox (NFX) are drugs used for its treatment; however, they are not efficacy in the chronic phase of the disease, which leads to high toxicity due to prolonged use. This research addresses the use of nanomaterials (Nano clay and VHS) as natural systems capable of adsorbing drugs with low water solubility, allowing improved release to reduce adverse effects. The objectives were to study the crystal structures of NFX and BNZ at the atomic scale, using quantum mechanics calculations and experimental techniques (XRD, FTIR, TGA, SEM-EDS), to understand their physicochemical characteristics in the crystalline state, as well as to explore their hydration by molecular dynamics simulations. The intercalation of these drugs in the confined space between the montmorillonite layers was evaluated by DFT calculations to propose novel clay-drug nanocomplexes for enhancing the solubility and bioavailability. The results showed that NFX intercalation in both clays presented a loss of crystallinity, with a displacement of the (001) plane, while BNZ exhibited slight intercalation being adsorbed mainly on the external surfaces of clay mineral solids. Montmorillonite enhanced the stability of these drugs through interactions (hydrogen bonding, electrostatic interactions, and coordination with Na+ cations), adopting parallel orientations with the clay layers. The intercalation of NFX and BNZ into the interlaminar space of montmorillonite was energetically favorable. The design of clay-drug nanocomplexes could be a potential alternative for developing new, more effective and safer therapeutic schemes against Chagas disease.
{"title":"Adsorption and intercalation of benznidazole and nifurtimox in montmorillonite: An experimental-theoretical study","authors":"Alexander Pérez de la Luz , Alfredo Jiménez-Mondragón , Miriam Soriano-Santiago , Julio C. Alva-Ensastegui , Ana María Soto-Estrada , José Luis Ortiz-Quiñonez , Linda Campos-Fernández , Carolina Barrientos-Salcedo , Víctor Hugo Lara-Corona , Edtson E. Herrera-Valencia , Catalina Soriano-Correa , C. Ignacio Sainz-Díaz","doi":"10.1016/j.clay.2026.108142","DOIUrl":"10.1016/j.clay.2026.108142","url":null,"abstract":"<div><div>American trypanosomiasis or Chagas disease, caused by <em>Trypanosoma cruzi</em>, remains a therapeutic challenge worldwide. Benznidazole (BNZ) and Nifurtimox (NFX) are drugs used for its treatment; however, they are not efficacy in the chronic phase of the disease, which leads to high toxicity due to prolonged use. This research addresses the use of nanomaterials (Nano clay and VHS) as natural systems capable of adsorbing drugs with low water solubility, allowing improved release to reduce adverse effects. The objectives were to study the crystal structures of NFX and BNZ at the atomic scale, using quantum mechanics calculations and experimental techniques (XRD, FTIR, TGA, SEM-EDS), to understand their physicochemical characteristics in the crystalline state, as well as to explore their hydration by molecular dynamics simulations. The intercalation of these drugs in the confined space between the montmorillonite layers was evaluated by DFT calculations to propose novel clay-drug nanocomplexes for enhancing the solubility and bioavailability. The results showed that NFX intercalation in both clays presented a loss of crystallinity, with a displacement of the (001) plane, while BNZ exhibited slight intercalation being adsorbed mainly on the external surfaces of clay mineral solids. Montmorillonite enhanced the stability of these drugs through interactions (hydrogen bonding, electrostatic interactions, and coordination with Na<sup>+</sup> cations), adopting parallel orientations with the clay layers. The intercalation of NFX and BNZ into the interlaminar space of montmorillonite was energetically favorable. The design of clay-drug nanocomplexes could be a potential alternative for developing new, more effective and safer therapeutic schemes against Chagas disease.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108142"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075297","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 : 2026-05-01Epub Date: 2026-01-26DOI: 10.1016/j.clay.2026.108128
Alex Spetz , Daniel Malmberg , Chang Seok Kim
The HotBENT experiment at the Grimsel Test Site investigates the Thermo-Hydro-Mechanical (THM) behaviour of bentonite clay at temperatures exceeding 100 °C. It consists of four heaters with a temperature of between 175 °C and 200 °C, encapsulated in two types of bentonites, Na dominated Wyoming bentonite and a Mg/Ca dominated BCV bentonite. Complementary to the field test, a multi-team modelling platform was established to develop numerical models of the experiment. This work presents the authors contribution to that platform, focusing on comparing how two different hydraulic parameterizations of Wyoming bentonite affected the numerical results compared with experimental measurements. The first parameterizations consisted of parameters provided to the HotBENT modelling platform and the second setup was based on parameters used in previous simulations of Wyoming bentonite, in for example, the license application for the Swedish nuclear waste repository.
2D axisymmetric THM simulations were carried out using COMSOL Multiphysics® and simulated the evolution during the first five years. Both parameter setups could successfully reproduce the general evolution in the test in terms of temperature and pore pressure evolution. However, significant differences could be seen in the modelled relative humidity (RH) evolution and dry density state.
The results highlight the importance of parameter selection when modelling coupled THM processes and the importance of using experimentally validated data.
{"title":"Evolution of thermo-hydro-mechanical behaviour of bentonite buffer at high temperature","authors":"Alex Spetz , Daniel Malmberg , Chang Seok Kim","doi":"10.1016/j.clay.2026.108128","DOIUrl":"10.1016/j.clay.2026.108128","url":null,"abstract":"<div><div>The HotBENT experiment at the Grimsel Test Site investigates the Thermo-Hydro-Mechanical (THM) behaviour of bentonite clay at temperatures exceeding 100 °C. It consists of four heaters with a temperature of between 175 °C and 200 °C, encapsulated in two types of bentonites, Na dominated Wyoming bentonite and a Mg/Ca dominated BCV bentonite. Complementary to the field test, a multi-team modelling platform was established to develop numerical models of the experiment. This work presents the authors contribution to that platform, focusing on comparing how two different hydraulic parameterizations of Wyoming bentonite affected the numerical results compared with experimental measurements. The first parameterizations consisted of parameters provided to the HotBENT modelling platform and the second setup was based on parameters used in previous simulations of Wyoming bentonite, in for example, the license application for the Swedish nuclear waste repository.</div><div>2D axisymmetric THM simulations were carried out using COMSOL Multiphysics® and simulated the evolution during the first five years. Both parameter setups could successfully reproduce the general evolution in the test in terms of temperature and pore pressure evolution. However, significant differences could be seen in the modelled relative humidity (RH) evolution and dry density state.</div><div>The results highlight the importance of parameter selection when modelling coupled THM processes and the importance of using experimentally validated data.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108128"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075296","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 : 2026-05-01Epub Date: 2026-01-16DOI: 10.1016/j.clay.2026.108125
José Manuel Moreno-Maroto , Noelia Cotón , Raúl Fernández , Marco A. Jiménez-González , Jacinto Alonso-Azcárate
The hydrothermal synthesis of zeopolymers (zeolite-geopolymer composites) using kaolin and marine plastic as a porogenic additive was studied, focusing on the influence of temperature and NaOH concentration. Spherical specimens (Ø 10 mm) were shaped from a kaolin-based mixture containing 5 wt% marine plastic and fired at 600 °C. These were subsequently subjected to hydrothermal treatment at 90, 120, and 150 °C under three different NaOH concentrations: 2, 3, and 4 mol/L. Results show that zeolitization is enhanced with increasing temperature and NaOH molarity, with zeolite A being predominant at 90 and 120 °C (33–44%), while cancrinite becomes dominant (47%) at 150 °C with 4 M NaOH. The reduction in total porosity after treatment, particularly at 90 °C, led to decreased water absorption and increased density in the resulting lightweight aggregates (1.66–1.82 g/cm3). Crushing strength improved markedly, rising from 0.1 MPa in the solely fired aggregates to 2.1–3.4 MPa in the zeopolymerized samples, a 19- to 30-fold increase. Notably, the samples treated at 150 °C with 2 M and 3 M NaOH combined high strength (3.4 MPa) with low density (1.66 and 1.70 g/cm3). A transport test on a zeolite A-rich sample showed strong ammonium adsorption capacity (Kd = 3782 L/kg), indicating its potential for water decontamination beyond structural uses. These findings highlight the key role of synthesis parameters in tailoring material properties, while emphasizing environmental benefits associated with marine plastic reuse (a major pollutant in marine ecosystems) and lower processing temperatures than in the ceramics industry and lightweight aggregates (600 °C vs. 900–1300 °C).
{"title":"Impact of temperature and NaOH concentration on the hydrothermal synthesis of zeopolymers (zeolite-geopolymer composites) from kaolin-marine plastic aggregates","authors":"José Manuel Moreno-Maroto , Noelia Cotón , Raúl Fernández , Marco A. Jiménez-González , Jacinto Alonso-Azcárate","doi":"10.1016/j.clay.2026.108125","DOIUrl":"10.1016/j.clay.2026.108125","url":null,"abstract":"<div><div>The hydrothermal synthesis of zeopolymers (zeolite-geopolymer composites) using kaolin and marine plastic as a porogenic additive was studied, focusing on the influence of temperature and NaOH concentration. Spherical specimens (Ø <span><math><mo>∼</mo></math></span> 10 mm) were shaped from a kaolin-based mixture containing 5 wt% marine plastic and fired at 600 °C. These were subsequently subjected to hydrothermal treatment at 90, 120, and 150 °C under three different NaOH concentrations: 2, 3, and 4 mol/L. Results show that zeolitization is enhanced with increasing temperature and NaOH molarity, with zeolite A being predominant at 90 and 120 °C (33–44%), while cancrinite becomes dominant (47%) at 150 °C with 4 M NaOH. The reduction in total porosity after treatment, particularly at 90 °C, led to decreased water absorption and increased density in the resulting lightweight aggregates (1.66–1.82 g/cm<sup>3</sup>). Crushing strength improved markedly, rising from 0.1 MPa in the solely fired aggregates to 2.1–3.4 MPa in the zeopolymerized samples, a 19- to 30-fold increase. Notably, the samples treated at 150 °C with 2 M and 3 M NaOH combined high strength (3.4 MPa) with low density (1.66 and 1.70 g/cm<sup>3</sup>). A transport test on a zeolite A-rich sample showed strong ammonium adsorption capacity (<em>K</em><sub>d</sub> = 3782 L/kg), indicating its potential for water decontamination beyond structural uses. These findings highlight the key role of synthesis parameters in tailoring material properties, while emphasizing environmental benefits associated with marine plastic reuse (a major pollutant in marine ecosystems) and lower processing temperatures than in the ceramics industry and lightweight aggregates (600 °C <em>vs.</em> 900–1300 °C).</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108125"},"PeriodicalIF":5.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145969250","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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