Applied Clay Science最新文献_第4页

Preparation of composite material sodium dodecyl sulfonate/2-methylimidazole zinc MOF/ palygorskite and its high- efficiency adsorption for tetracycline 十二烷基磺酸钠/2-甲基咪唑锌复合材料的制备及其对四环素的高效吸附

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-18 DOI: 10.1016/j.clay.2025.108057

Xin Li , Wen Chen , Jin-Long Jiang , Xia-ping Zhu , Ping Zhao

In this study, a one pot self-assembly strategy was adopted in aqueous solution to prepare a new material of sodium dodecyl sulfonate/2-methylimidazole zinc MOF/palygorskite (SDS/ZIF-8/PAL, abbreviated as SZP) with certain mesopores and high adsorption capacity for tetracycline. The material was prepared using surfactants such as sodium dodecyl sulfonate (SDS), Zn(NO₃)₂·6H₂O, 2-methylimidazole (2-MI) (maintaining 2-MI: Zn²⁺ = 10: 1), and palygorskite (PAL), and was environmentally friendly in both preparation and application. The saturated adsorption capacity of SZP was 914 mg/g at pH 7.0, temperature 298 K, adsorption time 180 min and ionic strength 0.01 mol/L, which was much higher than that of unmodified PAL and TC adsorption materials in other reports. X-ray photoelectron spectroscopy (XPS) analysis showed that SZP mainly removes TC through hydrogen bonding and coordination. Furthermore, SZP had good adsorption selectivity for TC, and the interference of dissolved organic substances, coexisting inorganic anions, cations and antibiotics with high detection rate in environmental water was small. And the removal rate was still above 90 % after five times of reuse. When SZP was applied to adsorb TC simulated water samples with different environmental water as the background, the concentration was 2.5 times of the highest concentration (20 mg/L) in actual aquaculture water, and the removal rate was up to 97 %. It showed that SZP can not only remove all TC from environmental water, but also its adsorption capacity far exceeds the pollution capacity, which indicated that SZP has potential application value in removing TC from environmental water.

本研究在水溶液中采用一锅自组装策略，制备了一种具有一定介孔且对四环素具有较高吸附能力的十二烷基磺酸钠/2-甲基咪唑锌MOF/坡高岭土新材料（SDS/ZIF-8/PAL，简称SZP）。该材料采用十二烷基磺酸钠（SDS）、Zn(NO3)2·6H2O、2-甲基咪唑（2- mi）（维持2- mi: Zn2+ = 10:1）和坡面石（PAL）等表面活性剂制备，制备和应用均具有环保性。在pH 7.0、温度298 K、吸附时间180 min、离子强度0.01 mol/L条件下，SZP的饱和吸附容量为914 mg/g，远高于其他报道的未改性PAL和TC吸附材料。x射线光电子能谱（XPS）分析表明，SZP主要通过氢键和配位去除TC。SZP对TC具有良好的吸附选择性，对环境水体中溶解有机物、共存的无机阴离子、阳离子和高检出率的抗生素干扰小。重复使用5次后，去除率仍在90%以上。应用SZP吸附不同环境水为背景的TC模拟水样时，浓度为实际养殖水中最高浓度（20 mg/L）的2.5倍，去除率可达97%。结果表明，SZP不仅可以去除环境水中的全部TC，而且其吸附量远远超过污染能力，这表明SZP在去除环境水中TC方面具有潜在的应用价值。

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引用次数: 0

OHSI – Onset Heat Size Index: A new parameter to predict rheology of cement-calcined clay blends OHSI起始热粒度指数：预测水泥-煅烧粘土共混物流变学的新参数

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-15 DOI: 10.1016/j.clay.2025.108044

M. Farjad Iqbal, Nishant Garg

Calcined clays (CCs) are promising supplementary cementitious materials given their potential for improving concrete durability and sustainability. However, they often cause high water demand and associated workability challenges. In this study, the rotational rheology of 16 cement and largely kaolinitic-CC blends was analyzed, revealing a wide range of dynamic yield stress (DYS) values (25–300 Pa). These DYS values strongly correlate with the ASTM C1437 paste flow, ranging from ∼30 % to 140 % (R² > 0.9). Interestingly, calorimetry results indicated that the rheological properties are linked to the onset heat (OH). By combining 3 unique parameters: OH, and particle size distribution (PSD) outputs (D₁₀ and D₅₀) a new parameter has been introduced, the onset heat size index (OHSI = OH/D₁₀·D₅₀). This OHSI can reliably predict the DYS (R² = 0.90, RMSE = 26 Pa), opening a pathway for employing widely adopted calorimetry and PSD measurements to simultaneously predict reactivity and rheology of cement-CC blended systems.

煅烧粘土（CCs）是很有前途的补充胶凝材料，因为它们具有提高混凝土耐久性和可持续性的潜力。然而，它们通常会导致高需水量和相关的可加工性挑战。在这项研究中，分析了16种水泥和大部分高岭石- cc共混物的旋转流变学，揭示了大范围的动态屈服应力（DYS）值（25-300 Pa）。这些DYS值与ASTM C1437膏体流量密切相关，范围从~ 30%到140% （R2 > 0.9）。有趣的是，量热结果表明，流变学性质与起始热（OH）有关。通过结合3个独特参数：OH和粒度分布（PSD）输出（D10和D50），引入了一个新的参数：起始热粒度指数（OHSI = OH/D10·D50）。该OHSI可以可靠地预测DYS (R2 = 0.90, RMSE = 26 Pa)，为采用广泛采用的量热法和PSD测量同时预测水泥- cc混合体系的反应性和流变性开辟了途径。

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引用次数: 0

Systematic review of physical, mechanical and durability performances of metakaolin concrete 偏高岭土混凝土物理、力学和耐久性性能的系统综述

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-15 DOI: 10.1016/j.clay.2025.108048

Mayen J. Geu, Yan Zhuge, Xing Ma, Thong M. Pham

The growing emphasis on environmental sustainability has significantly boosted research into metakaolin (MK)-based concrete as a viable alternative to traditional cement. The incorporation of MK enhances the mechanical and microstructural properties of concrete. Furthermore, it improves specific durability aspects, including chloride resistance, reduced permeability, and increased resistance to acid and alkali attacks. The overall enhancements arise from the small particle size's fill effect, improving packing density, and the pozzolanic reaction that produces additional gels, resulting in stronger and more durable concrete. However, the literature reveals mixed results concerning other durability factors, particularly carbonation resistance, water absorption, and shrinkage behaviour. Previous studies have indicated that a 10 % replacement reduced carbonation depth, and a 15 % MK dosage decreased capillary water absorption. In contrast, other investigations have highlighted potential drawbacks, including an increase in carbonation depth at 10–15 % MK replacement, a substantial dry shrinkage beyond 15 %, and greater water absorption at higher replacement levels. This review paper identifies and outlines research gaps in understanding how the structure of raw kaolinite influences its pozzolanic reactivity, mechanical performance, and durability properties in green concrete. The review paper consolidates key research findings on metakaolin, highlighting its durability properties as a partial replacement for cement, with an optimal level of 10–15 % MK in concrete.

对环境可持续性的日益重视极大地推动了对偏高岭土（MK）基混凝土作为传统水泥可行替代品的研究。MK的掺入提高了混凝土的力学性能和微观结构性能。此外，它还提高了特定的耐用性，包括抗氯化物、降低渗透性和增强抗酸碱侵蚀能力。整体的增强来自于小颗粒尺寸的填充效应，改善填料密度，以及火山灰反应产生额外的凝胶，从而产生更坚固和更耐用的混凝土。然而，文献揭示了其他耐久性因素的混合结果，特别是抗碳化、吸水和收缩行为。先前的研究表明，10%的替代量会降低碳化深度，15%的MK用量会降低毛细管吸水率。相比之下，其他研究也强调了潜在的缺点，包括在10 - 15% MK替换时碳酸化深度增加，超过15%时大量干缩，以及在更高的替换水平下更大的吸水率。这篇综述文章确定并概述了在理解生高岭石结构如何影响绿色混凝土中的火山灰反应性、机械性能和耐久性方面的研究空白。该综述论文整合了偏高岭土的主要研究成果，强调了其作为水泥部分替代品的耐久性，混凝土中的最佳MK水平为10 - 15%。

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引用次数: 0

Pore segmentation in electron micrographs: A probabilistic approach by ensemble machine learning 电子显微照片中的孔隙分割：一种基于集成机器学习的概率方法

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-14 DOI: 10.1016/j.clay.2025.108047

Marco Brysch , Ben Laurich , Monika Sester

In this study, an automatic method for segmenting pores in scanning electron microscopy images was developed. An ensemble of machine learning classifiers was combined with a fully connected conditional random field to obtain a spatial pore probability field. This field was then thresholded to produce coherent binary pore masks, and a confidence per pore

C_{l}

was defined to quantify the reliability of the segmentation. The approach was demonstrated on a broad-ion-beam polished sample of the shaley facies of the Opalinus Clay. Accurate segmentation enabled the derivation of pore size distributions (PSD), pore morphologies, orientations, and spatial statistics. By using the median of

C_{l}

per size range, a data-driven lower truncation limit for PSD fitting was established. The resulting microstructural metrics supported the interpretation of rock properties such as permeability. These results highlighted the method’s relevance for materials such as Opalinus Clay, which is investigated as a potential candidate for a host rock for nuclear waste storage.

本文研究了一种扫描电镜图像中孔隙的自动分割方法。将机器学习分类器集合与完全连接的条件随机场相结合，得到空间孔隙概率场。然后对该场进行阈值处理，生成相干的二元孔隙掩模，并定义每个孔隙的置信度Cl来量化分割的可靠性。该方法在蛋白石粘土泥质相的宽离子束抛光样品上得到了验证。精确的分割可以推导出孔径分布（PSD）、孔隙形态、方向和空间统计数据。通过使用每个尺寸范围的Cl的中位数，建立了数据驱动的PSD拟合的截断下限。由此产生的微观结构指标支持对岩石性质（如渗透率）的解释。这些结果突出了该方法与蛋白石粘土等材料的相关性，蛋白石粘土被研究为核废料储存的潜在候选宿主岩石。

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引用次数: 0

Hydrothermal vs. electrochemical synthesis of CaAl-layered double hydroxides smart pigments for steel corrosion protection 水热与电化学合成用于钢铁防腐的钙层双氢氧化物智能颜料

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-14 DOI: 10.1016/j.clay.2025.108045

Andrea Cristoforetti, Mitchell Tariro Harare, Michele Fedel

Intercalation efficiency and controlled release of organic molecules within CaAl-layered double hydroxides (LDHs) were investigated to develop smart pigments for corrosion protection of organic-coated steel. By systematically comparing hydrothermal and electrochemical syntheses, it is found that the electrochemical approach provides higher sebacate loading, whereas only autoclave post-treatment applied to either route leads to enhanced LDH crystallinity, smaller and more uniform particles, and greater inhibitor content (up to 40.9 wt%), and controlled release behavior. The improved structural features following autoclaving allow for a stronger link between release kinetics and overall corrosion protection performance. Hydrothermally prepared pigments display initially faster release and nobler corrosion potentials; however, post-treatment minimizes these differences and boosts the performance of electrochemical LDHs. The core novelty of this work lies in demonstrating that the interplay between tailored synthesis and post-synthesis treatment governs both the structure and function of LDH-based smart pigments. These findings provide practical guidance for the rational design of sustainable and effective inhibitors, highlighting the key relationships between LDH structure, inhibitor release, and protective efficacy on steel substrates.

研究了钙层双氢氧化物（calal -layered double hydroxides, LDHs）中有机分子的嵌入效率和控制释放，以开发用于有机涂层钢防腐的智能颜料。通过系统地比较水热合成和电化学合成，发现电化学方法提供了更高的脂酸负载，而仅采用高压灭菌后处理的任何一种方法都可以提高LDH的结晶度，更小更均匀的颗粒，更高的抑制剂含量（高达40.9 wt%），并具有可控的释放行为。经过改进的结构特征使得释放动力学和整体防腐性能之间的联系更加紧密。水热法制备的颜料最初表现出更快的释放速度和更高的腐蚀电位；然而，后处理可以最大限度地减少这些差异，并提高电化学LDHs的性能。这项工作的核心新颖之处在于证明了定制合成和合成后处理之间的相互作用决定了基于ldh的智能色素的结构和功能。这些发现为合理设计可持续和有效的抑制剂提供了实用指导，突出了LDH结构，抑制剂释放和对钢底物的保护效果之间的关键关系。

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引用次数: 0

Compositional-structural properties of the Opalinus Clay in southern Germany: Combining facies-based studies and mineralogical analyses 德国南部蛋白石粘土的组成-结构性质：结合相研究和矿物学分析

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-12 DOI: 10.1016/j.clay.2025.108032

Tilo Kneuker , Thomas Mann , Reiner Dohrmann , Kristian Ufer , Martin Blumenberg , Jochen Erbacher , André Bornemann , Bernhard Schuck , Géraldine Nicole Zimmerli , Lukas Pollok

The Middle Jurassic Opalinus Clay (OPA) in Switzerland and southern Germany is regarded as a potential host rock for the disposal of high-level radioactive waste. This study investigates sediment samples from drill cores taken from the Swabian Alb region (southern Germany), and employs a facies-based approach combined with mineralogical analyses, measurements of cation exchange capacity (CEC), and Rock-Eval pyrolysis. Special focus was given to the analysis of the degree of ordering of irregular illite-smectite interstratified clay minerals (I-S) that are responsible for the sorption of radionuclides and the swelling properties of the rocks.

The observations support the classification of OPA at the study site into three facies associations (FA-1: clay-rich lower part, FA-2: silty middle part, FA-3: silty upper part with interbedded calcareous-sandy beds), and further into subfacies (SF), in addition to the established twofold lithostratigraphic division into the Zillhausen and Teufelsloch Member. The percentages of clay fraction (<2 μm) varies across different lithofacies, correlating with variations in CEC.

Crystal structure-based Rietveld refinement indicates that the proportion of illitic layers in the I-S phase averages between 77 % and 83 % across all refinements and ordering types. No significant differences in the illite:smectite ratio of the I-S phases were observed between the two studied sites, however, a difference in the degree of ordering was identified. This variation may be attributed to differences in the burial history of the two localities and/or a mixture of different domains. A preliminary comparison with results from the OPA in Switzerland reveals that the average proportion of illite layers in the I-S (approximately 77 % for Mont Terri) closely aligns with the results observed in southern Germany.

The findings of this study underscore the importance of integrating lithofacies studies with mineralogical investigations to effectively assess the variability and comparability of clay-rich host rocks suitable for radioactive waste disposal.

瑞士和德国南部的中侏罗世蛋白石粘土（OPA）被认为是处置高放射性废物的潜在宿主岩石。本研究调查了来自Swabian Alb地区（德国南部）的岩心沉积物样本，并采用了基于相的方法，结合矿物学分析、阳离子交换容量（CEC）测量和岩石热解。特别着重分析了引起放射性核素吸收的不规则伊利石-蒙脱石层间粘土矿物（I-S）的有序程度和岩石的膨胀特性。观测结果支持了研究地点的OPA划分为3个相组合（FA-1：下部富粘土，FA-2：中部粉质，FA-3：上部粉质，钙质-砂质层互层），并进一步划分为亚相（SF），此外还建立了双重岩石地层划分为Zillhausen和Teufelsloch段。不同岩相的粘土分数（<2 μm）百分比不同，这与CEC的变化有关。基于晶体结构的Rietveld细化表明，在所有细化和有序类型中，I-S相中伊利石层的比例平均在77%到83%之间。在两个研究地点之间，没有观察到I-S相的伊利石：蒙脱石比例的显着差异，然而，在排序程度上存在差异。这种差异可能归因于两个地区埋葬历史的差异和/或不同地区的混合。与瑞士OPA结果的初步比较表明，在I-S中伊利石层的平均比例（蒙特特里约为77%）与在德国南部观察到的结果密切一致。本研究结果强调了将岩相研究与矿物学研究相结合的重要性，以有效评估适合放射性废物处置的富含粘土的寄主岩石的可变性和可比性。

{"title":"Compositional-structural properties of the Opalinus Clay in southern Germany: Combining facies-based studies and mineralogical analyses","authors":"Tilo Kneuker , Thomas Mann , Reiner Dohrmann , Kristian Ufer , Martin Blumenberg , Jochen Erbacher , André Bornemann , Bernhard Schuck , Géraldine Nicole Zimmerli , Lukas Pollok","doi":"10.1016/j.clay.2025.108032","DOIUrl":"10.1016/j.clay.2025.108032","url":null,"abstract":"<div><div>The Middle Jurassic Opalinus Clay (OPA) in Switzerland and southern Germany is regarded as a potential host rock for the disposal of high-level radioactive waste. This study investigates sediment samples from drill cores taken from the Swabian Alb region (southern Germany), and employs a facies-based approach combined with mineralogical analyses, measurements of cation exchange capacity (CEC), and Rock-Eval pyrolysis. Special focus was given to the analysis of the degree of ordering of irregular illite-smectite interstratified clay minerals (I-S) that are responsible for the sorption of radionuclides and the swelling properties of the rocks.</div><div>The observations support the classification of OPA at the study site into three facies associations (FA-1: clay-rich lower part, FA-2: silty middle part, FA-3: silty upper part with interbedded calcareous-sandy beds), and further into subfacies (SF), in addition to the established twofold lithostratigraphic division into the Zillhausen and Teufelsloch Member. The percentages of clay fraction (<2 μm) varies across different lithofacies, correlating with variations in CEC.</div><div>Crystal structure-based Rietveld refinement indicates that the proportion of illitic layers in the I-S phase averages between 77 % and 83 % across all refinements and ordering types. No significant differences in the illite:smectite ratio of the I-S phases were observed between the two studied sites, however, a difference in the degree of ordering was identified. This variation may be attributed to differences in the burial history of the two localities and/or a mixture of different domains. A preliminary comparison with results from the OPA in Switzerland reveals that the average proportion of illite layers in the I-S (approximately 77 % for Mont Terri) closely aligns with the results observed in southern Germany.</div><div>The findings of this study underscore the importance of integrating lithofacies studies with mineralogical investigations to effectively assess the variability and comparability of clay-rich host rocks suitable for radioactive waste disposal.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"279 ","pages":"Article 108032"},"PeriodicalIF":5.8,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526235","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}

引用次数: 0

The incorporation of thymol and carvacrol in bentonites: Influence of functionalization and the resulting antibacterial activities 百里香酚和香芹酚在膨润土中的掺入：功能化的影响及其抗菌活性

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-11 DOI: 10.1016/j.clay.2025.108028

Luís H. Oliveira , Idglan S. de Lima , Denise B. França , Albert S. Silva , Santiago Medina-Carrasco , Maria del Mar Orta , Josy A. Osajima , Maria G. Fonseca , Edson C. da Silva-Filho

Incorporating essential oils or their components into inorganic matrices has been used as a strategy to slow release of these species, reducing the rapid volatility of the oils. Thymol and carvacrol are among the essential oil components that have diverse bioactivities. This study evaluated the incorporation of thymol and carvacrol in sodium bentonite (Na-Bent) and bentonite functionalized with aminopropyltrimethoxysilane (NH₂-Bent). The systems were characterized by short- and long-range structural, morphological, and thermal techniques. The agar diffusion test evaluated the antibacterial activity of the hybrids against Staphylococcus aureus and Escherichia coli. X-ray diffraction (XRD) patterns confirmed the intercalation of silane into clay and the formation of intercalation hybrids of oils in both matrices. ²⁹Si NMR suggested covalently immobilization of the silane on clay surface. ¹³C nuclear magnetic resonance (¹³C NMR), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) spectra indicated the presence of oils in clays and the contribution of hydrogen bonding and Van der Waals force between the species. The maximum incorporation of the compounds occurred in the silylated sample, resulting in 2.14 and 2.40 mmol g^-1 for thymol and carvacrol, respectively. The silylated samples also presented a slower release profile of thymol and carvacrol compared to the Na-Bent sample. The antibacterial action that resulted in inhibition diameters was more significant than that of the positive control. The promising data also included the controlled release of thymol and carvacrol, resulting in the antibacterial action of the hybrids.

将精油或其成分加入无机基质中已被用作减缓这些物种释放的策略，减少油的快速挥发性。百里酚和香芹酚是具有多种生物活性的精油成分。研究了百里香酚和香芹酚在钠基膨润土（Na-Bent）和氨基丙基三甲氧基硅烷（NH2-Bent）膨润土中的掺入情况。通过结构、形态和热技术对该体系进行了表征。琼脂扩散试验评价了杂交种对金黄色葡萄球菌和大肠杆菌的抑菌活性。x射线衍射（XRD）证实了硅烷在粘土中嵌入，并在两种基质中形成了油的嵌入杂化。29Si核磁共振表明硅烷在粘土表面共价固定。13C核磁共振（13C NMR）、x射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）分析结果表明，粘土中存在油类物质，且油类之间存在氢键和范德华力。在硅基化的样品中，化合物的掺入量最大，百里香酚和香芹酚的掺入量分别为2.14和2.40 mmol g-1。与Na-Bent样品相比，硅烷化样品也呈现出较慢的百里酚和香芹酚释放谱。其抑菌作用显著高于阳性对照。有希望的数据还包括控制百里香酚和香芹酚的释放，导致杂交种的抗菌作用。

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引用次数: 0

Mineralogical drivers of fertility and pedogenetic processes in tropical mountain soils of southeastern Brazil 巴西东南部热带山地土壤肥力和成土过程的矿物学驱动因素

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-06 DOI: 10.1016/j.clay.2025.108031

Ramon Machado Loureiro , David Lukas de Arruda , Artur Henrique Nascimento da Silva , Marcelo Metri Corrêa , Danilo de Lima Camêlo

The mineralogical composition of the clay fraction plays a fundamental role in the chemical evolution and natural fertility of tropical soils, particularly in mountainous environments where intense weathering interacts with slope-driven lateral fluxes. This study investigated the mineralogical transformations and pedogenetic processes that govern soil fertility in residual soils developed from syenogranite in the Caparaó mountain region, southeastern Brazil. An integrated analytical approach was employed, including X-ray diffraction (Newmod II modeling), geochemical mass balance (τ), specific surface area, and micromorphological characterization. Although kaolinite is the dominant clay mineral across profiles, surface horizons contained appreciable proportions of interstratified 2:1 clay minerals, including illite–vermiculite and kaolinite–illite, indicating ongoing transformation of primary micas (biotite > > muscovite). The progressive alteration of biotite, mainly in B horizons, together with positive τ values for Si and exchangeable bases in A and C horizons, reflects the combined action of vertical differentiation and colluvial renewal. The latter, through selective supply of weatherable minerals from upslope lithological sources, sustains the formation of more reactive clay phases, enhances cation exchange capacity, and contributes to nutrient retention even under advanced weathering conditions. Micromorphological evidence of clay coatings, b-fabrics, Fe/Mn hypo- and quasi-coatings, and mangano-ferruginous nodules supports the co-occurrence of limited clay illuviation and redox-mediated Fe/Mn redistribution, particularly in Bt and Bw horizons. These pedofeatures indicate the interplay between vertically driven differentiation and slope-controlled hydrological and redox oscillations. Altogether, the results demonstrate that the natural fertility of these tropical mountain soils is sustained by the integrated operation of vertical and lateral processes, which together maintain dynamic mineralogical renewal, chemical resilience, and long-term fertility, a mechanism particularly relevant for low-input agricultural systems such as specialty coffee production in southeastern Brazil.

粘土组分的矿物学组成在热带土壤的化学演化和自然肥力中起着根本作用，特别是在山地环境中，强烈的风化作用与斜坡驱动的侧向通量相互作用。本研究研究了巴西东南部Caparaó山区正长花岗岩残土中控制土壤肥力的矿物学转化和成土过程。采用综合分析方法，包括x射线衍射（Newmod II建模）、地球化学质量平衡（τ）、比表面积和微形态表征。虽然高岭石在剖面上是主要的粘土矿物，但地表层含有相当比例的层间2:1粘土矿物，包括伊利石-蛭石和高岭石-伊利石，表明原生云母（黑云母>； >；白云母）正在发生转化。黑云母主要发生在B层的递进蚀变，以及A和C层Si和交换碱的正τ值，反映了垂向分异和崩塌更新的共同作用。后者通过选择性地供应来自上坡岩性来源的耐候性矿物，维持了更具反应性的粘土相的形成，增强了阳离子交换能力，即使在先进的风化条件下也有助于营养物质的保留。粘土包覆层、b-组构、Fe/Mn亚包覆层和准包覆层以及锰-铁结核的微观形态证据支持了有限粘土照明和氧化还原介导的Fe/Mn再分配的共存，特别是在Bt和Bw层。这些土壤特征表明垂直驱动的分异与斜坡控制的水文和氧化还原振荡之间存在相互作用。总之，研究结果表明，这些热带山地土壤的自然肥力是由垂直和横向过程的综合运作维持的，这些过程共同维持了动态矿物学更新、化学弹性和长期肥力，这一机制与巴西东南部的精品咖啡生产等低投入农业系统特别相关。

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引用次数: 0

Effect of MgO content on high-temperature phase transformation of kaolinitic coal gangue and on the production of cordierite MgO含量对高岭石型煤矸石高温相变及堇青石生产的影响

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-03 DOI: 10.1016/j.clay.2025.108030

Jintao Li , Qinfu Liu , Kuo Li , Yakui Li , Naisheng Jiang

Utilizing kaolinitic coal gangue as raw material for cordierite synthesis presents substantial implications for environmental sustainability, economic viability, and technological advancement in coal mining areas. This study systematically investigated the crystalline phase evolution during thermal treatment of kaolinitic coal gangue (Ningwu Coalfield, Shanxi, China) with 0–20 wt% MgO doping. Characterization by multiple analytical methods (X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and high-resolution transmission electron microscopy) revealed distinct crystalline phase transformation pathways. Undoped systems exhibited sequential phase transitions from kaolinite to metakaolinite and ultimately to mullite. In MgO-doped systems, MgO preferentially reacts with amorphous SiO₂ and amorphous Al₂O₃ derived from high-temperature phase transformation of kaolinite/boehmite, initiating spinel and forsterite formation while competitively reducing mullite crystallization. Mullite serves as a critical intermediate phase for cordierite formation, supplying the essential aluminum required for its crystallization. MgO-doped systems exhibited three cordierite crystallization pathways governed by MgO content: (i) Spinel reacts with silica to form cordierite; (ii) Forsterite combines with mullite and silica to form cordierite under Mg-deficient conditions; (iii) Forsterite converting to enstatite, then reacting with mullite and silica to yield cordierite under Mg-enriched conditions. Furthermore, optimal cordierite yield was achieved at 10–15 wt% MgO. These findings validate coal gangue as a viable precursor for high-value ceramic production, proposing an innovative waste-to-resource strategy for the coal industry.

利用高岭石型煤矸石作为合成堇青石的原料，对矿区的环境可持续性、经济可行性和技术进步具有重要意义。本研究系统地研究了掺0 ~ 20 wt% MgO的高岭石型煤矸石（山西宁武煤田）在热处理过程中的晶相演化。通过多种分析方法（x射线衍射、差示扫描量热法、扫描电镜和高分辨率透射电镜）的表征揭示了不同的晶体相变途径。未掺杂体系表现出从高岭石到偏高岭石，最后到莫来石的顺序相变。在MgO掺杂体系中，MgO优先与高岭石/薄水铝石高温相变产生的无定形sio2和无定形Al₂O₃反应，引发尖晶石和forsterite的形成，同时竞争性地减少莫来石的结晶。莫来石是堇青石形成的关键中间相，为堇青石的结晶提供必需的铝。MgO掺杂体系表现出三种受MgO含量控制的堇青石结晶途径：(i)尖晶石与二氧化硅反应生成堇青石；在缺镁条件下，橄榄石与莫来石和二氧化硅结合形成堇青石；(3)在富镁条件下，橄榄石转化为顽辉石，再与莫来石和二氧化硅反应生成堇青石。此外，最佳堇青石产量达到10-15 wt%的MgO。这些发现证实了煤矸石是高价值陶瓷生产的可行前体，为煤炭工业提出了一种创新的废物转化资源战略。

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引用次数: 0

Hierarchical porous kaolinite microspheres for leakage-resistant and high-conductivity phase change composites in advanced thermal energy storage 分级多孔高岭石微球用于防泄漏和高导电性相变复合材料的先进热能储存

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-11-01 DOI: 10.1016/j.clay.2025.108029

Qian Zhang , Xiaoguang Zhao , Xiaochao Zuo , Huaming Yang

The growing global energy demand and environmental concerns necessitate innovative thermal energy storage solutions. Phase change materials (PCMs), particularly organic PCMs like stearic acid (SA), offer high latent heat storage capacity but face challenges such as leakage and low thermal conductivity. This study presents a novel strategy to synthesize hierarchical porous honeycomb kaolinite (HPCK) microspheres via spray drying, calcination, and hydrothermal reconstruction for encapsulating SA. The HPCK/SA composite form-stable PCM (CFSPCM) demonstrates superior thermal performance, with a melting enthalpy of 104.6 J/g and crystallization enthalpy of 105.4 J/g, alongside enhanced shape stability and thermal conductivity (0.51 W/m·K). Structural characterization reveals that HPCK's hierarchical porosity (BET surface area of 220.1 m²/g, 0.76 cm³/g pore volume) effectively immobilizes SA through physical interactions, preventing leakage even at 90 °C. Cyclic stability tests confirm retention of 90 % latent heat after 200 thermal cycles. This work advances the design of clay-based CFSPCMs for scalable applications in building thermal management, solar energy storage, and industrial waste heat recovery.

不断增长的全球能源需求和环境问题需要创新的热能储存解决方案。相变材料（PCMs），特别是硬脂酸（SA）等有机相变材料（PCMs）具有高潜热储存能力，但面临泄漏和低导热性等挑战。本研究提出了一种通过喷雾干燥、煅烧和水热重构制备层叠多孔蜂窝高岭石微球的新策略。HPCK/SA复合稳形PCM （CFSPCM）表现出优异的热性能，熔融焓为104.6 J/g，结晶焓为105.4 J/g，同时增强了形状稳定性和导热系数（0.51 W/m·K）。结构表征表明，HPCK的分层孔隙度（BET表面积为220.1 m2/g，孔隙体积为0.76 cm3/g）通过物理相互作用有效地固定了SA，即使在90°C下也能防止泄漏。循环稳定性试验证实，在200个热循环后，潜热保留率为90%。这项工作推进了基于粘土的cfspcm的设计，可扩展应用于建筑热管理，太阳能储能和工业废热回收。

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