Here, new film materials (oak tree acorn starch-clove essential oil (CEO)-halloysite nanotube (HNT) films) were prepared for the first time using naturally abundant oak tree acorns and halloysite nanotube clay minerals, and a natural product (clove essential oil, CEO). The characterization of the fabricated film materials was performed by FTIR, opacity, water contact angle, color, water vapor permeability, mechanical analysis and thermal gravimetric analysis measurements. The presence of HNT or CEO within starch film matrix increased the opacity value of starch film with increasing HNT or CEO concentration. The improved water vapor barrier properties of starch film were achieved by using HNT and CEO in the film formulation. By using 5% HNT into the starch film matrix, the improvements of 87.5% in the maximum tensile stress and 108% in the Young's modulus of the starch film were obtained. In the preparation of starch-based film materials, the use of HNT improved the thermal stability of film material while CEO had an opposite effect. It was determined that instead of CEO, the use of CEO-encapsulated HNT in the preparation of starch-based antibacterial composite films caused a slower release of CEO from bioplastic film. Starch-based films containing CEO showed antibacterial property against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. The experimental results revealed that low-cost and eco-friendly oak tree acorn starch- CEO- HNT bioplastic films are promising for the food packaging sector.
{"title":"Preparation and characterization of oak tree acorn starch-based bioplastic composite films reinforced with halloysite nanotube and clove essential oil","authors":"Tülin Gürkan Polat , Osman Duman , Selin Sağdıç , Şerife Çelik , Sibel Tunç","doi":"10.1016/j.clay.2026.108129","DOIUrl":"10.1016/j.clay.2026.108129","url":null,"abstract":"<div><div>Here, new film materials (oak tree acorn starch-clove essential oil (CEO)-halloysite nanotube (HNT) films) were prepared for the first time using naturally abundant oak tree acorns and halloysite nanotube clay minerals, and a natural product (clove essential oil, CEO). The characterization of the fabricated film materials was performed by FTIR, opacity, water contact angle, color, water vapor permeability, mechanical analysis and thermal gravimetric analysis measurements. The presence of HNT or CEO within starch film matrix increased the opacity value of starch film with increasing HNT or CEO concentration. The improved water vapor barrier properties of starch film were achieved by using HNT and CEO in the film formulation. By using 5% HNT into the starch film matrix, the improvements of 87.5% in the maximum tensile stress and 108% in the Young's modulus of the starch film were obtained. In the preparation of starch-based film materials, the use of HNT improved the thermal stability of film material while CEO had an opposite effect. It was determined that instead of CEO, the use of CEO-encapsulated HNT in the preparation of starch-based antibacterial composite films caused a slower release of CEO from bioplastic film. Starch-based films containing CEO showed antibacterial property against both Gram-negative (<em>E. coli</em>) and Gram-positive (<em>S. aureus</em>) bacteria. The experimental results revealed that low-cost and eco-friendly oak tree acorn starch- CEO- HNT bioplastic films are promising for the food packaging sector.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108129"},"PeriodicalIF":5.8,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025207","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 : 2026-01-17DOI: 10.1016/j.clay.2026.108122
Bao Ren , Yafei Tan , Fanfei Min , Mengyu Li , Mingkang Xu , Chunfu Liu
The hydration characteristics of fine tailings particles constrain settling and dewatering efficiency. While the two-step flocculation process is a promising approach to overcome this bottleneck, optimization is impeded by the unclear microscopic mechanism underlying sequence effects. Combining molecular dynamics (MD) simulations and kaolinite sedimentation tests, this study reveals how the dosing sequence of hydrophobic associative cationic flocculant (PAMT) with conventional flocculants (CPAM, APAM, NPAM) affects flocculation mechanisms. Results demonstrated that dosing PAMT first effectively controls particle aggregation and the interfacial microenvironment. Employing the sequence of PAMT followed by APAM (P + A combination) reduced turbidity to 31.50 NTU and increased initial settling rate to 92.88 m/h, thereby overcoming the functional limitations of single flocculants. Mechanistically, prior PAMT addition activated the dual-surface characteristics of kaolinite, forming a hydrogen bond network on the aluminol surface and enhancing electrostatic anchoring on the siloxane surface. Simultaneously, hydrophobic fluorocarbon chains of PAMT reduced interfacial water density, weakening the hydration layer and promoting dewatering. The P + A combination leveraged charge complementarity between the cationic and anionic flocculants, forming extensive and continuous molecular chain distributions on the kaolinite surface, which established a stable flocculation bridging mechanism. In the reverse sequence (A + P combination), the steric hindrance layer formed by APAM on the particle surface restricted contact with the hydrophobic groups of PAMT, hindering intra-floc hydrophobic association. Additionally, combinations involving CPAM (P + C, C + P) exhibited dosage sensitivity due to electrostatic repulsion between molecular chains, while those incorporating nonionic NPAM (P + N, N + P) showed weakened synergy due to the absence of ionic charges.
细粒尾矿的水化特性制约了其沉降和脱水效率。虽然两步絮凝工艺是克服这一瓶颈的一种有希望的方法，但由于序列效应的微观机制不明确，阻碍了优化。本研究结合分子动力学（MD）模拟和高岭石沉降试验，揭示了疏水缔合阳离子絮凝剂（PAMT）与常规絮凝剂（CPAM、APAM、NPAM）的投加顺序对絮凝机理的影响。结果表明，PAMT的投加首先有效地控制了颗粒聚集和界面微环境。采用PAMT + APAM （P + A组合）的顺序将浊度降低到31.50 NTU，初始沉降速率提高到92.88 m/h，从而克服了单一絮凝剂的功能限制。在机理上，先前添加的PAMT激活了高岭石的双表面特性，在铝醇表面形成氢键网络，并增强了硅氧烷表面的静电锚定。同时，PAMT的疏水性氟碳链降低了界面水密度，削弱了水化层，促进了脱水。P + A组合利用阳离子和阴离子絮凝剂之间的电荷互补，在高岭石表面形成广泛而连续的分子链分布，建立了稳定的絮凝桥接机制。相反顺序（A + P组合），APAM在颗粒表面形成的位阻层限制了与PAMT疏水基团的接触，阻碍了絮团内的疏水结合。此外，含有CPAM （P + C, C + P）的组合由于分子链之间的静电排斥而表现出剂量敏感性，而含有非离子型NPAM （P + N, N + P）的组合由于缺乏离子电荷而表现出较弱的协同作用。
{"title":"Bridging mechanism of a hydrophobically associating cationic flocculant in kaolinite settling during two-step flocculation","authors":"Bao Ren , Yafei Tan , Fanfei Min , Mengyu Li , Mingkang Xu , Chunfu Liu","doi":"10.1016/j.clay.2026.108122","DOIUrl":"10.1016/j.clay.2026.108122","url":null,"abstract":"<div><div>The hydration characteristics of fine tailings particles constrain settling and dewatering efficiency. While the two-step flocculation process is a promising approach to overcome this bottleneck, optimization is impeded by the unclear microscopic mechanism underlying sequence effects. Combining molecular dynamics (MD) simulations and kaolinite sedimentation tests, this study reveals how the dosing sequence of hydrophobic associative cationic flocculant (PAMT) with conventional flocculants (CPAM, APAM, NPAM) affects flocculation mechanisms. Results demonstrated that dosing PAMT first effectively controls particle aggregation and the interfacial microenvironment. Employing the sequence of PAMT followed by APAM (P + A combination) reduced turbidity to 31.50 NTU and increased initial settling rate to 92.88 m/h, thereby overcoming the functional limitations of single flocculants. Mechanistically, prior PAMT addition activated the dual-surface characteristics of kaolinite, forming a hydrogen bond network on the aluminol surface and enhancing electrostatic anchoring on the siloxane surface. Simultaneously, hydrophobic fluorocarbon chains of PAMT reduced interfacial water density, weakening the hydration layer and promoting dewatering. The P + A combination leveraged charge complementarity between the cationic and anionic flocculants, forming extensive and continuous molecular chain distributions on the kaolinite surface, which established a stable flocculation bridging mechanism. In the reverse sequence (A + P combination), the steric hindrance layer formed by APAM on the particle surface restricted contact with the hydrophobic groups of PAMT, hindering intra-floc hydrophobic association. Additionally, combinations involving CPAM (P + C, C + P) exhibited dosage sensitivity due to electrostatic repulsion between molecular chains, while those incorporating nonionic NPAM (P + N, N + P) showed weakened synergy due to the absence of ionic charges.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108122"},"PeriodicalIF":5.8,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025286","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 : 2026-01-16DOI: 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":"2026-01-16","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}
This study investigates the coupled roles of diffuse double layer (DDL) development and ion exchange in cation adsorption onto Na-bentonite. Batch adsorption tests and free swell tests were conducted over a wide range of initial CaCl2 molarities (0–1000 mmol/L), and both Ca2+ adsorption and Na+ release were quantified. The ion exchange dominated the Ca2+ adsorption when the equilibrium bulk Ca2+ molarity (Ce) was below 1 mmol/L, whereas the majority of Ca2+ adsorption was associated with DDL development. The measured adsorbed molality (qeCa, mmol/g) exhibited a non-monotonic trend with respect to Ce. When qeCa was normalized to adsorbed molarity (Cin, mmol/L) by accounting for the experimentally evaluated volume of DDL domain, the resulting molar adsorption isotherm exhibited a Langmuir-type correlation, indicating that the adsorption equilibrium was dependent on Langmuir equilibrium constant KL. This result emphasized that the DDL constituted a dynamic spatial domain governing cation adsorption process, while the adsorption equilibrium was governed by the correlation between Ce and Cin. This framework provides a physically consistent interpretation of DDL development and ion exchange to the cation adsorption onto bentonite, thereby advancing the mechanistic understanding of clay-water interactions relevant to bentonite-based barrier systems in geoenvironmental engineering.
{"title":"The roles of diffuse double layer development and ion exchange in cation adsorption onto bentonite in aqueous system","authors":"Rongguang Yu, Atsushi Takai, Tomohiro Kato, Takeshi Katsumi","doi":"10.1016/j.clay.2026.108123","DOIUrl":"10.1016/j.clay.2026.108123","url":null,"abstract":"<div><div>This study investigates the coupled roles of diffuse double layer (DDL) development and ion exchange in cation adsorption onto Na-bentonite. Batch adsorption tests and free swell tests were conducted over a wide range of initial CaCl<sub>2</sub> molarities (0–1000 mmol/L), and both Ca<sup>2+</sup> adsorption and Na<sup>+</sup> release were quantified. The ion exchange dominated the Ca<sup>2+</sup> adsorption when the equilibrium bulk Ca<sup>2+</sup> molarity (<em>C</em><sub>e</sub>) was below 1 mmol/L, whereas the majority of Ca<sup>2+</sup> adsorption was associated with DDL development. The measured adsorbed molality (<em>q</em><sub>eCa</sub>, mmol/g) exhibited a non-monotonic trend with respect to <em>C</em><sub>e</sub>. When <em>q</em><sub>eCa</sub> was normalized to adsorbed molarity (<em>C</em><sub>in</sub>, mmol/L) by accounting for the experimentally evaluated volume of DDL domain, the resulting molar adsorption isotherm exhibited a Langmuir-type correlation, indicating that the adsorption equilibrium was dependent on Langmuir equilibrium constant <em>K</em><sub>L</sub>. This result emphasized that the DDL constituted a dynamic spatial domain governing cation adsorption process, while the adsorption equilibrium was governed by the correlation between <em>C</em><sub>e</sub> and <em>C</em><sub>in</sub>. This framework provides a physically consistent interpretation of DDL development and ion exchange to the cation adsorption onto bentonite, thereby advancing the mechanistic understanding of clay-water interactions relevant to bentonite-based barrier systems in geoenvironmental engineering.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"284 ","pages":"Article 108123"},"PeriodicalIF":5.8,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976436","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 : 2026-01-12DOI: 10.1016/j.clay.2026.108127
Haizhen Li , Mengqian Qi , Wensheng Yang , Jiateng Hu , Mengjiao Niu , Yongshuai Xie , Tianliang Wang , Gang Yu
The deep activation process of natural clay minerals, which leads to surface modification and optimization of pore structures, plays a critical role in enhancing their practical applicability in composite phase change materials. In this study, a novel ultrasound-assisted acidification approach was developed to produce activated sepiolite fibers for the fabrication of paraffin/sepiolite composite PCMs, exhibiting superior thermal stability and energy storage performance. The ultrasonic-assisted acidification method enables effective fiber dissociation and removal of associated mineral impurities in sepiolite fibers, thereby preserving structural integrity, generating optimal porous channels, and increasing surface areas up to 308.82 m2/g. The activated sepiolite fiber with specific surface area and pore size of 142.2 m2/g and 9.1 nm, enables the paraffin/sepiolite composite phase change material (UHP/S3–1) to achieve the highest latent heat of fusion and crystallization, reaching 106.72 J/g and 107.86 J/g, respectively. Moreover, the mechanical oscillation and cavitation effects generated by ultrasound strengthened the synergistic interaction between the acidification process and ultrasound irradiation, enabling the effective use of weak organic acids, such as acetic acid (HAc), as the acidifying agent. UAP/S5–1 prepared using HAc-acidified sepiolite fibers with ultrasound irradiation, exhibits excellent structural stability, thermal reliability, and reusability at temperatures below 80 °C after 100 thermal cycles, resulting in strong chemical binding interactions (COO- group) between paraffin and activated sepiolite fibers. This work provides a prospective strategy for constructing stable mineral-based composite PCMs with excellent energy storage performance for their practical application thermal management.
{"title":"Ultrasonic-assisted acidification of sepiolite fibers towards highly stable paraffin-based phase change composites with enhanced thermal energy storage performance","authors":"Haizhen Li , Mengqian Qi , Wensheng Yang , Jiateng Hu , Mengjiao Niu , Yongshuai Xie , Tianliang Wang , Gang Yu","doi":"10.1016/j.clay.2026.108127","DOIUrl":"10.1016/j.clay.2026.108127","url":null,"abstract":"<div><div>The deep activation process of natural clay minerals, which leads to surface modification and optimization of pore structures, plays a critical role in enhancing their practical applicability in composite phase change materials. In this study, a novel ultrasound-assisted acidification approach was developed to produce activated sepiolite fibers for the fabrication of paraffin/sepiolite composite PCMs, exhibiting superior thermal stability and energy storage performance. The ultrasonic-assisted acidification method enables effective fiber dissociation and removal of associated mineral impurities in sepiolite fibers, thereby preserving structural integrity, generating optimal porous channels, and increasing surface areas up to 308.82 m<sup>2</sup>/g. The activated sepiolite fiber with specific surface area and pore size of 142.2 m<sup>2</sup>/g and 9.1 nm, enables the paraffin/sepiolite composite phase change material (UHP/S3–1) to achieve the highest latent heat of fusion and crystallization, reaching 106.72 J/g and 107.86 J/g, respectively. Moreover, the mechanical oscillation and cavitation effects generated by ultrasound strengthened the synergistic interaction between the acidification process and ultrasound irradiation, enabling the effective use of weak organic acids, such as acetic acid (HAc), as the acidifying agent. UAP/S5–1 prepared using HAc-acidified sepiolite fibers with ultrasound irradiation, exhibits excellent structural stability, thermal reliability, and reusability at temperatures below 80 °C after 100 thermal cycles, resulting in strong chemical binding interactions (COO- group) between paraffin and activated sepiolite fibers. This work provides a prospective strategy for constructing stable mineral-based composite PCMs with excellent energy storage performance for their practical application thermal management.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108127"},"PeriodicalIF":5.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973492","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 : 2026-01-09DOI: 10.1016/j.clay.2026.108121
Jinyao He , Xueyu Du , Pengfei Wang , Yan Cui , Yongjun Li , Yong Chen
Developing efficient and low-cost adsorbents is crucial for CO hazards. This study created a modified sepiolite via synergistic acid-hydrothermal-Cu+ treatment, achieving dramatically enhanced CO adsorption. The sequential treatment effectively removed impurities, repaired structural defects, and yielded a stabilized mesoporous structure, increasing the specific surface area by approximately 99 %. The optimal loading of 10 wt% Cu supported on Sep-HCl-HT reduced the outlet CO concentration from 105 ppm to 2 ppm effectively, corresponding to a remarkable adsorption efficiency of 98.2 %. Combined with characterization and molecular dynamics simulations, the increased surface area of sepiolite support benefited for the highly dispersed Cu+ species, and the Cu+ species were further stabilized via substituting the framework Mg2+ of sepiolite. The strong d-π backbonding between Cu+ and CO molecules conduced to the excellent CO adsorption.
开发高效、低成本的吸附剂是解决CO危害的关键。本研究通过酸-热液- cu +协同处理制备了改性海泡石，显著增强了CO的吸附能力。顺序处理有效地去除杂质，修复结构缺陷，并产生稳定的介孔结构，增加了约99%的比表面积。最佳负载量为10 wt%的Cu，可有效地将出口CO浓度从105 ppm降低到2 ppm，吸附效率为98.2%。结合表征和分子动力学模拟，海泡石载体表面积的增加有利于Cu+物种的高度分散，Cu+物种通过取代海泡石的框架Mg2+而进一步稳定。Cu+和CO分子之间的强d-π背键导致了优异的CO吸附性能。
{"title":"Experimental and molecular modeling study of CO adsorption on modified sepiolite","authors":"Jinyao He , Xueyu Du , Pengfei Wang , Yan Cui , Yongjun Li , Yong Chen","doi":"10.1016/j.clay.2026.108121","DOIUrl":"10.1016/j.clay.2026.108121","url":null,"abstract":"<div><div>Developing efficient and low-cost adsorbents is crucial for CO hazards. This study created a modified sepiolite via synergistic acid-hydrothermal-Cu<sup>+</sup> treatment, achieving dramatically enhanced CO adsorption. The sequential treatment effectively removed impurities, repaired structural defects, and yielded a stabilized mesoporous structure, increasing the specific surface area by approximately 99 %. The optimal loading of 10 wt% Cu supported on Sep-HCl-HT reduced the outlet CO concentration from 105 ppm to 2 ppm effectively, corresponding to a remarkable adsorption efficiency of 98.2 %. Combined with characterization and molecular dynamics simulations, the increased surface area of sepiolite support benefited for the highly dispersed Cu<sup>+</sup> species, and the Cu<sup>+</sup> species were further stabilized via substituting the framework Mg<sup>2+</sup> of sepiolite. The strong d-π backbonding between Cu<sup>+</sup> and CO molecules conduced to the excellent CO adsorption.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108121"},"PeriodicalIF":5.8,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922397","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 : 2026-01-07DOI: 10.1016/j.clay.2025.108101
Axel Neißer-Deiters, Sebastian Scherb, Nancy Beuntner, Karl-Christian Thienel
Calcined clays (CCs) are a promising supplementary cementitious material to advance decarbonization of cement, even though they are a challenge in rheology. The study focuses on the interaction of CCs, pore solution ions, and superplasticizer to improve rheology with CC. This was done with four illitic and smectitic dominated CCs in cement-free aqueous solutions. Rheometry, infrared spectroscopy, electroacoustic measurements, X-ray diffraction, and water absorption capacity measurements were conducted to investigate superplasticizer intercalation and adsorption, hydration, surface charge, ion adsorption, and rheology. Yield stress increased in synthetic cement pore solution in comparison to deionized water. This was not attributed to hydration products or a change in pH value, but explained by Derjaguin–Landau–Verwey–Overbeek theory (DLVO) due to changed zeta potential and ion concentration. CCs can adsorb anionic superplasticizers onto their negatively charged surface. With calcium addition, their surface charge polarity was reversed, and superplasticizer adsorption increased drastically. Superplasticizer demand seemed independent of sulfate addition, which is contradictory with cement systems. Superplasticizer demand was twice as high for illitic CCs compared to smectitic CCs. Intercalation of superplasticizers and swelling of calcined smectite can be excluded. The results confirmed BET specific surface area as a generally good indicator for superplasticizer demand of CCs, but it is not sufficient for differentiation within similar mineralogy. These findings help to further establish CCs further as an eco-friendly but also workable supplementary cementitious material.
{"title":"Rheology of calcined illitic and smectitic clays in cement-free aqueous solutions with a focus on ion adsorption and superplasticizer interaction","authors":"Axel Neißer-Deiters, Sebastian Scherb, Nancy Beuntner, Karl-Christian Thienel","doi":"10.1016/j.clay.2025.108101","DOIUrl":"10.1016/j.clay.2025.108101","url":null,"abstract":"<div><div>Calcined clays (CCs) are a promising supplementary cementitious material to advance decarbonization of cement, even though they are a challenge in rheology. The study focuses on the interaction of CCs, pore solution ions, and superplasticizer to improve rheology with CC. This was done with four illitic and smectitic dominated CCs in cement-free aqueous solutions. Rheometry, infrared spectroscopy, electroacoustic measurements, X-ray diffraction, and water absorption capacity measurements were conducted to investigate superplasticizer intercalation and adsorption, hydration, surface charge, ion adsorption, and rheology. Yield stress increased in synthetic cement pore solution in comparison to deionized water. This was not attributed to hydration products or a change in pH value, but explained by Derjaguin–Landau–Verwey–Overbeek theory (DLVO) due to changed zeta potential and ion concentration. CCs can adsorb anionic superplasticizers onto their negatively charged surface. With calcium addition, their surface charge polarity was reversed, and superplasticizer adsorption increased drastically. Superplasticizer demand seemed independent of sulfate addition, which is contradictory with cement systems. Superplasticizer demand was twice as high for illitic CCs compared to smectitic CCs. Intercalation of superplasticizers and swelling of calcined smectite can be excluded. The results confirmed BET specific surface area as a generally good indicator for superplasticizer demand of CCs, but it is not sufficient for differentiation within similar mineralogy. These findings help to further establish CCs further as an eco-friendly but also workable supplementary cementitious material.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108101"},"PeriodicalIF":5.8,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922396","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 : 2026-01-06DOI: 10.1016/j.clay.2026.108120
Tianqi Zhang , Qi Tao , Jinming Bao , Xinman Xu , Xiaorong Qin , Xiaoliang Liang , Hongping He
This study addresses the limitations of individual mineral phases for paleoenvironmental reconstruction on Mars, by investigating smectite-associated mineral assemblages formed across a broad pH range (pH = 4–13). Hydrothermal experiments reveal that aluminum content controls iron crystallization pathways under acidic conditions. Low aluminum content favors direct nontronite formation, while high aluminum content leads to iron (hydr)oxide precipitation. Under oxidizing environments, moderately acidic conditions enhance Fe/Mg enrichment, explaining the elevated Fe/Mg ratios observed in Martian smectites. With increasing pH toward alkaline conditions, zeolite species shift from gobbinsite to phillipsite, and analcime crystal morphology changes from purely cubic to a combination of cubic and tetragonal trisoctahedra between pH 10 and 13. These trends make smectite-zeolite assemblages promising diagnostic indicators of alkalinity. Raman spectroscopy reliably distinguishes zeolite species, overcoming visible and near-infrared reflectance (VNIR) technology limitations. Furthermore, evaporite minerals exhibit exquisite sensitivity to variations in temperature and humidity, undergoing structural transitions (e.g., Na2SO4-III → Na2SO4-V) and ionic substitution (e.g., hexahydrite → blödite; thermonatrite and sodium sulfate → burkeite). These pose challenges for reliable paleoenvironmental reconstruction and Mars sample return curation. These results provide a mineralogical framework for deciphering smectite-related aqueous environments on Mars.
{"title":"Mineral assemblages with smectites in simulated basalt alteration: implications for Martian aqueous environments","authors":"Tianqi Zhang , Qi Tao , Jinming Bao , Xinman Xu , Xiaorong Qin , Xiaoliang Liang , Hongping He","doi":"10.1016/j.clay.2026.108120","DOIUrl":"10.1016/j.clay.2026.108120","url":null,"abstract":"<div><div>This study addresses the limitations of individual mineral phases for paleoenvironmental reconstruction on Mars, by investigating smectite-associated mineral assemblages formed across a broad pH range (pH = 4–13). Hydrothermal experiments reveal that aluminum content controls iron crystallization pathways under acidic conditions. Low aluminum content favors direct nontronite formation, while high aluminum content leads to iron (hydr)oxide precipitation. Under oxidizing environments, moderately acidic conditions enhance Fe/Mg enrichment, explaining the elevated Fe/Mg ratios observed in Martian smectites. With increasing pH toward alkaline conditions, zeolite species shift from gobbinsite to phillipsite, and analcime crystal morphology changes from purely cubic to a combination of cubic and tetragonal trisoctahedra between pH 10 and 13. These trends make smectite-zeolite assemblages promising diagnostic indicators of alkalinity. Raman spectroscopy reliably distinguishes zeolite species, overcoming visible and near-infrared reflectance (VNIR) technology limitations. Furthermore, evaporite minerals exhibit exquisite sensitivity to variations in temperature and humidity, undergoing structural transitions (e.g., Na<sub>2</sub>SO<sub>4</sub>-III → Na<sub>2</sub>SO<sub>4</sub>-<em>V</em>) and ionic substitution (e.g., hexahydrite → blödite; thermonatrite and sodium sulfate → burkeite). These pose challenges for reliable paleoenvironmental reconstruction and Mars sample return curation. These results provide a mineralogical framework for deciphering smectite-related aqueous environments on Mars.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108120"},"PeriodicalIF":5.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922394","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 : 2026-01-05DOI: 10.1016/j.clay.2025.108111
Lea Ruckes , Matthias Maier , Alisa Machner
Mechanochemical activation (MCA) of phyllosilicates is one of the most promising solutions to produce reactive supplementary cementitious materials (SCMs). Several studies have already shown that MCA outperforms thermal activation (TA) in terms of reactivity when clays are low in kaolinite but rich in 2:1 phyllosilicates. Because reactivity depends on phyllosilicate type as well as content, and clays vary widely, a quick and simple test is needed to assess raw material suitability. Therefore, the aim of this study was to investigate the mineralogical and physical properties of common clays and their impact on reactivity after MCA, as well as their suitability as SCM. Hence, a multi-method approach was used to determine the reactivity of seven German common clays after TA and MCA and their use as SCM. The R3-test was used to determine the evolved heat after 7 days. Thermal analysis showed an altered OH binding that went along with a decrease in surface area with prolonged milling. Through Rietveld refinement of the X-ray diffraction analysis and the external standard method, the amorphous content of the phyllosilicates was determined. An increase in the amorphous content was observed after MCA. The solubility of Al and Si could also be correlated with the reactivity of the phyllosilicates. The concentration of all ions increased with prolonged milling time, and therefore also correlated linearly with the reactivity. Both the loss of dehydroxylation area and the Si:Al solubility ratio served as practical, rapid screening tools for raw-material suitability.
{"title":"Parameters affecting the pozzolanic reactivity of common clays after mechanochemical activation","authors":"Lea Ruckes , Matthias Maier , Alisa Machner","doi":"10.1016/j.clay.2025.108111","DOIUrl":"10.1016/j.clay.2025.108111","url":null,"abstract":"<div><div>Mechanochemical activation (MCA) of phyllosilicates is one of the most promising solutions to produce reactive supplementary cementitious materials (SCMs). Several studies have already shown that MCA outperforms thermal activation (TA) in terms of reactivity when clays are low in kaolinite but rich in 2:1 phyllosilicates. Because reactivity depends on phyllosilicate type as well as content, and clays vary widely, a quick and simple test is needed to assess raw material suitability. Therefore, the aim of this study was to investigate the mineralogical and physical properties of common clays and their impact on reactivity after MCA, as well as their suitability as SCM. Hence, a multi-method approach was used to determine the reactivity of seven German common clays after TA and MCA and their use as SCM. The R<sup>3</sup>-test was used to determine the evolved heat after 7 days. Thermal analysis showed an altered OH binding that went along with a decrease in surface area with prolonged milling. Through Rietveld refinement of the X-ray diffraction analysis and the external standard method, the amorphous content of the phyllosilicates was determined. An increase in the amorphous content was observed after MCA. The solubility of Al and Si could also be correlated with the reactivity of the phyllosilicates. The concentration of all ions increased with prolonged milling time, and therefore also correlated linearly with the reactivity. Both the loss of dehydroxylation area and the Si:Al solubility ratio served as practical, rapid screening tools for raw-material suitability.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108111"},"PeriodicalIF":5.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922454","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}
Talc plays an essential role in transporting water into the mantle via subduction zones. The compressional behavior of triclinic (C) talc under high pressure was investigated by a combination of synchrotron X-ray diffraction (XRD), infrared (IR) spectroscopy, and density functional theory (DFT) calculations. Talc exhibited exceptional structural stability with no observable crystallographic phase transitions up to ∼20 GPa, as determined by synchrotron-based high-pressure XRD. However, a notable change occurs in the hydroxyl groups above ∼10 GPa: the OH bond length, which plateaus at ∼0.9687 Å below this pressure, shows a subsequent linear decrease. The structure of talc shows strong anisotropic compressibility: the decrease of a-, b-, and c-axis is 4.4 %, 5.0 %, and 9.0 % throughout the investigated pressure regime, respectively. Most of the compression is taken up by the weakly bonded interlayer regions below ∼10 GPa. The unit-cell volume changed continuously with pressure, but the F-fE plot indicates a change in compressibility around ∼10 GPa. The PV data below and above 10 GPa were fitted separately using the third-order Birch-Murnaghan equation of state. The derived parameters are as follows: K0 = 55.0(67) GPa and K′ = 11.0(52) below 10 GPa, and K0 = 59.2(19) GPa and K′ = 5.2(4) above 10 GPa for XRD results with V0 fitted as 455.5(9) Å3; V0 = 451.4(5) Å3, K0 = 41.2(18) GPa, and K′ = 8.2(8) below 10 GPa, and V0 = 445.2(8) Å3, K0 = 56.9(14) GPa, and K′ = 5.1(1) above 10 GPa for DFT results. Our findings contribute to a better understanding of hydroxyl groups in response to pressure in layered-structure silicates, offering insights into talc's roles in geological processes and the deep-Earth water cycle.
{"title":"High-pressure structural evolution of talc investigated by X-ray diffraction, infrared spectroscopy, and density functional theory calculations","authors":"Bingxu Hou , Jingjing Niu , Lili Zhang , Hongrui Ding , Fei Qin , Yanzhang Li , Shan Qin , Anhuai Lu , Hongyan Zuo","doi":"10.1016/j.clay.2026.108119","DOIUrl":"10.1016/j.clay.2026.108119","url":null,"abstract":"<div><div>Talc plays an essential role in transporting water into the mantle via subduction zones. The compressional behavior of triclinic (<em>C</em><span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>) talc under high pressure was investigated by a combination of synchrotron X-ray diffraction (XRD), infrared (IR) spectroscopy, and density functional theory (DFT) calculations. Talc exhibited exceptional structural stability with no observable crystallographic phase transitions up to ∼20 GPa, as determined by synchrotron-based high-pressure XRD. However, a notable change occurs in the hydroxyl groups above ∼10 GPa: the O<img>H bond length, which plateaus at ∼0.9687 Å below this pressure, shows a subsequent linear decrease. The structure of talc shows strong anisotropic compressibility: the decrease of <em>a</em>-, <em>b</em>-, and <em>c</em>-axis is 4.4 %, 5.0 %, and 9.0 % throughout the investigated pressure regime, respectively. Most of the compression is taken up by the weakly bonded interlayer regions below ∼10 GPa. The unit-cell volume changed continuously with pressure, but the <em>F</em>-<em>f</em><sub>E</sub> plot indicates a change in compressibility around ∼10 GPa. The <em>P</em><img><em>V</em> data below and above 10 GPa were fitted separately using the third-order Birch-Murnaghan equation of state. The derived parameters are as follows: <em>K</em><sub>0</sub> = 55.0(67) GPa and <em>K</em>′ = 11.0(52) below 10 GPa, and <em>K</em><sub>0</sub> = 59.2(19) GPa and <em>K</em>′ = 5.2(4) above 10 GPa for XRD results with <em>V</em><sub>0</sub> fitted as 455.5(9) Å<sup>3</sup>; <em>V</em><sub>0</sub> = 451.4(5) Å<sup>3</sup>, <em>K</em><sub>0</sub> = 41.2(18) GPa, and <em>K</em>′ = 8.2(8) below 10 GPa, and <em>V</em><sub>0</sub> = 445.2(8) Å<sup>3</sup>, <em>K</em><sub>0</sub> = 56.9(14) GPa, and <em>K</em>′ = 5.1(1) above 10 GPa for DFT results. Our findings contribute to a better understanding of hydroxyl groups in response to pressure in layered-structure silicates, offering insights into talc's roles in geological processes and the deep-Earth water cycle.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"283 ","pages":"Article 108119"},"PeriodicalIF":5.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922393","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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