Applied Clay Science最新文献_第10页

Effect of thermal aging at 165 °C–200 °C on bentonite performance 165℃- 200℃热老化对膨润土性能的影响

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-17 DOI: 10.1016/j.clay.2025.107994

Sirpa Kumpulainen , Jari Martikainen , Teemu Laurila , Florian Kober , Olivier Leupin

The engineered barrier system in the deep geological repository will encounter varying design loads (hydraulic, mechanical, thermal and chemical) over time. The bentonite buffer may remain dry for long periods of time locally, where access to water from the host rock is low, and consequently, heat may build up increasing the buffer temperature leading to dehydration of smectite. The temperature for complete removal of interlayer water on the smectite is within >150 °C and depends on among others exchangeable cation, smectite type and confining pressure. Although dehydration reactions can be considered reversible, complete dehydration may lead to irreversible alterations. The objective of this work was to determine the effect of thermal aging on bentonite buffer performance.

Bentonite from Wyoming was thermally aged at 165 °C, 180 °C or 200 °C for 4 weeks, 8 weeks or 20 weeks in a dry, unsaturated state. Thereafter, bentonite was cooled down to room temperature and its properties and performance were evaluated determining the mineralogy by X-ray diffraction (XRD), cation exchange capacity (CEC), swelling index, and performing swelling pressure and hydraulic conductivity tests. Swiss repository conditions were applied for this work using granular bentonite mixture (GBM) and a target dry density of 1450 kg/m³ and Opalinus Clay synthetic porewater (TDS of 16.92 g/l) in swelling pressure and hydraulic conductivity experiments.

Mineralogical changes observed include dehydration of gypsum and change in clay suspension color indicating small changes in iron oxide mineral phases or contents. No impact on the swelling pressure was noted due to thermal aging, but thermally aged samples had a factor of 1.8 higher hydraulic conductivity compared to references. In addition, up to 4 % decrease in apparent CEC, and up to 25 % decrease in swelling index and faster settling of clay suspensions were observed to occur with thermal aging time and temperature. One potential explanation for observed changes is partial fixation of exchangeable cations and consequent changes in particle size due to heat exposure.

随着时间的推移，深层地质储存库中的工程屏障系统将遇到不同的设计载荷（水力、机械、热和化学）。膨润土缓冲层可能在局部保持干燥很长一段时间，因为从宿主岩石中获得的水分很少，因此，热量可能会积聚，增加缓冲层的温度，导致蒙脱石脱水。完全去除蒙脱石层间水的温度在150℃以内，这取决于交换阳离子、蒙脱石类型和围压等因素。虽然脱水反应可以被认为是可逆的，但完全脱水可能导致不可逆的改变。本工作的目的是确定热老化对膨润土缓冲性能的影响。怀俄明州的膨润土在165°C， 180°C或200°C下在干燥，不饱和状态下热老化4周，8周或20周。随后，将膨润土冷却至室温，通过x射线衍射（XRD）、阳离子交换容量（CEC）、溶胀指数、溶胀压力和水导率测试等方法对膨润土的矿物学特征进行评价。本研究采用瑞士储库条件，采用颗粒状膨润土混合物（GBM），目标干密度为1450 kg/m3， Opalinus Clay合成孔隙水（TDS为16.92 g/l）进行膨胀压力和水力导率实验。观察到的矿物学变化包括石膏脱水和粘土悬浮液颜色的变化，表明氧化铁矿物相或含量的微小变化。热老化对膨胀压力没有影响，但热老化样品的水力导率比参考样品高1.8倍。此外，随着热老化时间和温度的增加，表观CEC降低了4%，膨胀指数降低了25%，粘土悬浮物的沉降速度加快。对观察到的变化的一个可能的解释是，由于热暴露，可交换阳离子的部分固定和随之而来的颗粒大小变化。

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引用次数: 0

Carvacrol-loaded montmorillonite–caseinate hybrids as active additives for the development of antimicrobial alginate-chitosan microcapsules carvacrol负载蒙脱石-酪蛋白酸盐杂交体作为活性添加剂开发海藻酸盐-壳聚糖抗菌微胶囊

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-17 DOI: 10.1016/j.clay.2025.107996

Mohamed Brahmi , Sara Moumnassi , Kamal Essifi , Emilie Dumas , Abdeslam Asehraou , Abdesselam Tahani , Adem Gharsallaoui

This study presented a novel approach for encapsulating carvacrol, a volatile compound with antimicrobial properties, using montmorillonite-based hybrid materials prepared via an evaporation–adsorption process under vacuum at room temperature. These hybrids were incorporated as active additives into alginate-chitosan microcapsules. The effect of montmorillonite surface functionalization was examined by preparing two types of carvacrol-loaded composites: one with sodium caseinate intercalated within the clay layers, and another with caseinate adsorbed onto the external surface. Among these, the intercalated composite (Cas0.5@Mt-3) showed the highest carvacrol adsorption capacity, reaching 176.87 mg/g compared to 155.83 mg/g for the unmodified clay. This enhancement was attributed to the diffusion of carvacrol into the interlayer space, as supported by XRD analysis showing increased interlayer spacing.

The carvacrol-loaded hybrids were incorporated into alginate matrices at three concentrations (1 %, 2 %, and 3 % w/w) using ionotropic gelation to form stable microcapsules. Higher encapsulation efficiency and loading capacity were achieved with the hybrid composites, likely due to the amphiphilic nature of caseinate, which improved compatibility between the additive and the polymeric matrix, as confirmed by FT-IR and TGA analysis.

In vitro release studies in food-simulating media revealed more controlled carvacrol release in aqueous medium, while acidic and oily conditions led to faster diffusion. Antimicrobial tests against selected strains demonstrated enhanced inhibition, attributed to the synergistic effect of carvacrol and the polymeric components, particularly chitosan used for crosslinking. These results supported the effectiveness of this approach and its potential for developing active polymer-based systems to improve carvacrol bioavailability in food-related applications.

本研究提出了一种新的方法来封装香芹酚，一种具有抗菌性能的挥发性化合物，使用蒙脱土基杂化材料，通过真空蒸发-吸附工艺在室温下制备。将这些杂合物作为活性添加剂掺入海藻酸壳聚糖微胶囊中。通过制备两种负载卡罗罗的蒙脱土表面功能化的效果进行了研究：一种是将酪蛋白酸钠嵌入到粘土层中，另一种是将酪蛋白酸钠吸附到外表面。其中，插层复合材料（Cas0.5@Mt-3）对香芹酚的吸附量最高，达到176.87 mg/g，而未改性粘土的吸附量为155.83 mg/g。这种增强是由于carvacrol扩散到层间空间，XRD分析表明层间空间增加。将负载香芹酚的杂交种以三种浓度（1%、2%和3% w/w）的海藻酸盐基质中通过离子化凝胶形成稳定的微胶囊。FT-IR和TGA分析证实，这种杂化复合材料具有更高的包封效率和负载能力，这可能是由于酪蛋白酸盐的两亲性，从而改善了添加剂与聚合物基体之间的相容性。在模拟食物介质中的体外释放研究表明，在水介质中，香芹酚的释放更受控制，而酸性和油性条件下，香芹酚的扩散速度更快。对选定菌株的抗菌试验表明，由于香芹酚和聚合物组分，特别是用于交联的壳聚糖的协同作用，抑制作用增强。这些结果支持了该方法的有效性及其开发活性聚合物体系的潜力，以提高香芹酚在食品相关应用中的生物利用度。

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引用次数: 0

Clay mineral formation via interstratified phases in Luvisols formed from amphibolite, northeastern Brazil 巴西东北部角闪岩形成的luvisol的层间相粘土矿物形成

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-17 DOI: 10.1016/j.clay.2025.107995

Artur Henrique Nascimento da Silva , Gabriel Ramatis Pugliese Andrade , Sheila Aparecida Correia Furquim , Fábio Soares de Oliveira , Marilya Gabryella de Sousa , Marcelo Metri Correa , Ygor Jacques Agra Bezerra da Silva , Juliet Emília Santos de Sousa , Tiago Osório Ferreira , Xose Lois Otero , Valdomiro Souza Junior

The transformations of clay minerals in Luvisols formed on amphibolite under contrasting semi-arid climates in northeastern Brazil were examined to understand how weathering intensity drives the development of mixed-layer minerals (MLMs) and affects key soil properties. Two Chromic Luvisols, developed from similar amphibolite parent material, each representing distinct climatic conditions (Profile 1: annual precipitation = 415 mm yr⁻¹; Profile 2: = 777 mm yr⁻¹) were sampled across their A, B, and Cr horizons. X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetry and Mössbauer spectroscopy were used to characterize the clay fractions and their interstratified minerals. The results revealed that both soils predominantly feature interstratified kaolinite–smectite (KS) phases, with Profile 1 showing higher proportions of expandable smectite layers. In contrast, Profile 2 exhibited a greater enrichment in kaolinitic layers at all depths. Notably, this study demonstrates that the pedogenetic clay minerals in natural Luvisols from the Brazilian semiarid region consist of transitional MLMs rather than discrete endmembers. It also shows that climatic variation influenced the soil mineralogical composition, primarily through changes in the mixed-layer phases.

研究了巴西东北部半干旱气候条件下角闪岩上形成的luvisol中粘土矿物的转化，以了解风化强度如何驱动混合层矿物（MLMs）的发育并影响关键的土壤性质。从相似的角闪岩母物质中发育而来的两个铬色luvisol分别代表不同的气候条件（剖面1：年降水量= 415 mm yr - 1；剖面2:= 777 mm yr - 1）在A、B和Cr层上取样。利用x射线衍射、傅里叶变换红外光谱、热重和Mössbauer光谱对粘土组分及其层间矿物进行了表征。结果表明，两种土壤均以层间高岭石-蒙脱石（KS）相为主，剖面1中可膨胀蒙脱石层的比例较高。剖面2各深度高岭石层富集程度较高。值得注意的是，本研究表明，来自巴西半干旱地区的天然luvisol中的成土粘土矿物由过渡性mlm组成，而不是离散的端元。气候变化对土壤矿物学成分的影响主要是通过混合层相的变化。

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引用次数: 0

Large-area hybrid silver/nickel-iron layer double hydroxide on metallic tube array for highly sensitive surface-enhanced Raman scattering (SERS) application 金属管阵列上大面积混合银/镍铁层双氢氧化物用于高灵敏度表面增强拉曼散射（SERS）

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-13 DOI: 10.1016/j.clay.2025.107986

Balasubramanian Sriram , Alfreda Krisna Altama , Elaiyappillai Elanthamilan , Yi-Le Liao , Sea-Fue Wang , Jinn P. Chu

This paper presented a novel method for the preparation of hybrid metallic tube arrays (MeTA) with Ag coated nickel‑iron layered double hydroxide (LDH) as highly sensitive surface-enhanced Raman scattering (SERS) substrates for the detection of toxic dyes. Nickel‑iron LDH was used as a two-dimensional material with a brucite-like structure featured a large surface area and excellent adsorption capacity. This study leveraged the sharp edges of the array structures in conjunction with the plasmonic properties of silver (a noble metal) to amplify local electromagnetic fields to create plasmonic hot spots. A hybrid heterojunction composed of Ag and LDH on MeTA enhanced the capacity of the substrate to absorb target analytes such as rhodamine 6G (R6G) and malachite green (MG). The substrate demonstrated enhanced SERS performance, as indicated by high enhancement factors in the detection of R6G (2.6 × 10⁸) and MG (1.8 × 10⁶). The arrays exhibited a broad linear dynamic range (R6G: 10⁻⁴ to 10⁻¹⁴ mol L⁻¹; MG: 10⁻⁴ to 10⁻¹⁰ mol L⁻¹), exceeded the ranges reported in previous studies. The structure of the array also revealed good reproducibility and variability. In addition, the limit of detection for R6G was determined to be 6.0 × 10⁻⁹ mol L⁻¹ based on band height calibration and 2.57 × 10⁻⁹ mol L⁻¹ based on band height ratio calibration, respectively. These results underscored the importance of adsorption capacity in developing advanced SERS substrates.

本文提出了一种以镀银镍铁层状双氢氧化物（LDH）作为高灵敏度表面增强拉曼散射（SERS）底物制备杂化金属管阵列（MeTA）的新方法，用于检测有毒染料。镍铁LDH作为一种二维材料，具有类似水镁石的结构，具有较大的表面积和优异的吸附能力。这项研究利用阵列结构的尖锐边缘和银（一种贵金属）的等离子体特性来放大局部电磁场，从而产生等离子体热点。在MeTA上由Ag和LDH组成的杂化异质结增强了底物吸收目标分析物如罗丹明6G （R6G）和孔雀石绿（MG）的能力。通过检测R6G （2.6 × 108）和MG （1.8 × 106）的高增强因子，表明该底物具有增强的SERS性能。该阵列具有较宽的线性动态范围（R6G: 10−4 ~ 10−14 mol L−1;MG: 10−4 ~ 10−10 mol L−1），超出了以往研究的范围。该阵列的结构也显示出良好的再现性和可变性。此外，基于带高校正R6G的检出限为6.0 × 10−9 mol L−1，基于带高比校正R6G的检出限为2.57 × 10−9 mol L−1。这些结果强调了吸附能力在开发先进SERS底物中的重要性。

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引用次数: 0

Author's response to “Discussion on ‘Design of acid-geopolymers based on clays by-products for methylene blue removal from wastewater’ [Applied Clay Science 245 (2023) 107126]” and corrigendum to our recent paper [https://doi.org/10.1016/j.clay.2023.107126] 作者对“基于粘土副产物的酸性地聚合物设计用于去除废水中亚甲基蓝的讨论”的回应[应用粘土科学245(2023)107126]和我们最近论文的更正[https://doi.org/10.1016/j.clay.2023.107126]]

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-11 DOI: 10.1016/j.clay.2025.107984

Salma En-naji , Sara Ghazi , Hanaa Mabroum , Safaa Mabroum , Khalid Khatib , Yassine Taha , Inés García Lodeiro , Rachid Hakkou

引用次数: 0

Insight into the spiral growth of disordered kaolinite nanocrystals 无序高岭石纳米晶体螺旋生长的深入研究

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-06 DOI: 10.1016/j.clay.2025.107981

Yongjie Yang , Long Chen , Jiale Pu , Qiang Luo , Maguy Jaber , Christelle Souprayen , Ning Wang , Qinfu Liu

Structural disorder in kaolinite critically shapes its reactivity and performance across environmental and industrial contexts. Insights into spiral growth offer a mechanistic framework to decode the structural disorder of kaolinite and advance our understanding of its formation and properties. We identified a distinct expansion of the (001) interlayer spacing, from ∼7.16 Å in well-ordered kaolinite to ∼7.21 Å in disordered samples, along with selective enhancement of the (020) reflection in disordered nanocrystals. This structural disorder is closely linked to Al(4)-for-Si(4) substitution, with a high Al(4)/Al total ratio (∼2.83 %). The ionic radius ratio of

R_{{Al}^{III} (4)}

_:

R_{O^{2 -}}

=0.438 substantially exceeds that of ideal tetrahedral packing, compared to

R_{{Si}^{IV} (4)}

_:

R_{O^{2 -}}

=0.331, generating internal stress that exceeds the structural tolerance of triclinic kaolinite. When this stress exceeds a critical threshold, it likely promotes the formation of screw dislocations, which initiate spiral growth and generating stacking faults and in-plane lattice rotations (∼5°), as evidenced by Moiré fringe patterns and SAED. Spiral growth thus acts as a stress-adaptive mechanism, enabling the crystal to accommodate structural instability while maintaining long-range order and anisotropic deformation. These findings recast disorder as a stress-regulated growth strategy and offer a mechanistic blueprint for tuning structure in low-dimensional layered materials.

高岭石的结构紊乱严重影响其在环境和工业背景下的反应性和性能。对螺旋生长的深入了解提供了一个机制框架来解读高岭石的结构紊乱，并促进我们对其形成和性质的理解。我们发现（001）层间距明显扩大，从有序高岭石中的~ 7.16 Å到无序样品中的~ 7.21 Å，同时无序纳米晶体中的（020）反射选择性增强。这种结构紊乱与Al(4)-for-Si(4)取代密切相关，具有高Al(4)/Al总比（~ 2.83%）。与RSiIV4:RO2−=0.331相比，RAlIII4:RO2−=0.438的离子半径比大大超过了理想四面体填料，产生的内应力超出了三斜高岭石的结构承受能力。当该应力超过临界阈值时，它可能促进螺旋位错的形成，螺旋位错启动螺旋生长并产生层错和面内晶格旋转（~ 5°），正如莫尔条纹图和SAED所证明的那样。因此，螺旋生长作为一种应力适应机制，使晶体能够适应结构不稳定性，同时保持长程有序和各向异性变形。这些发现将无序重新定义为应力调节的生长策略，并为低维层状材料的结构调整提供了机制蓝图。

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引用次数: 0

Mechanochemical effect assisted oxidative whitening of black talc 机械化学效应辅助黑滑石氧化增白

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-03 DOI: 10.1016/j.clay.2025.107961

Huan Shuai , Xianrong Yang , Xi Xu , Gaoxiang Du , Jiao Wang

Black talc, a carbon-intercalated phyllosilicate mineral, is significantly limited in industrial applications due to its intrinsic low whiteness. Conventional whitening methods relying on high-temperature calcination inevitably compromise its layered crystalline structure through thermal decomposition. This study presents a mechanochemically assisted oxidative strategy that achieves effective whitening while preserving structural integrity. By combining mechanical exfoliation with oxidative activation, the interlayer graphite carbon domains in black talc were selectively oxidized, thus significantly increasing the whiteness. Compared with mechanical treatment alone (whiteness 25.7) or chemical treatment alone (whiteness 52.4), the synergistic coupling of mechanical activation and oxidant (whiteness 75.7) increased the whitening efficiency by 626 % and 299 %, respectively. Systematic characterization via X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed a synergistic mechanism: (i) mechanical delamination exposing encapsulated carbon layers and (ii) surface activation promoting oxidative radical generation for carbon removal. Notably, the layered framework remained intact post-treatment, as evidenced by maintained interlayer spacing and absence of phase transformation, contrasting sharply with the structural collapse observed in calcination-based approaches. Although current exploration focuses on carbonaceous minerals, this mechanochemical paradigm establishes a versatile platform for high-value utilization of heat-sensitive mineral resources, particularly in applications demanding structural preservation, such as functional composites and precision ceramics manufacturing.

黑滑石是一种碳插层层状硅酸盐矿物，由于其固有的低白度，在工业应用中受到很大限制。传统的依靠高温煅烧的增白方法不可避免地会因热分解而破坏其层状晶体结构。本研究提出了一种机械化学辅助氧化策略，在保持结构完整性的同时实现有效的美白。通过机械剥离和氧化活化相结合的方法，对黑色滑石层间石墨碳畴进行了选择性氧化，从而显著提高了白度。与机械单独处理（白度25.7）或化学单独处理（白度52.4）相比，机械活化与氧化剂协同耦合（白度75.7）的增白效率分别提高了626%和299%。通过x射线光电子能谱（XPS）和热重分析（TGA）的系统表征揭示了协同机制：(i)机械分层暴露包裹的碳层；（ii）表面活化促进氧化自由基生成以去除碳。值得注意的是，层状框架在处理后保持完整，层间间距保持不变，没有发生相变，这与基于煅烧的方法观察到的结构崩塌形成鲜明对比。虽然目前的勘探主要集中在碳质矿物上，但这种机械化学模式为热敏性矿产资源的高价值利用建立了一个多功能平台，特别是在要求结构保存的应用中，如功能复合材料和精密陶瓷制造。

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引用次数: 0

Thiol functionalized kaolin pellets: Development and optimization for mercury ion removal from aqueous solutions 硫醇功能化高岭土颗粒：开发和优化从水溶液中去除汞离子

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-02 DOI: 10.1016/j.clay.2025.107983

Awal Adava Abdulsalam , Madina Pirman , Dilnaz Begenova , George Z. Kyzas , Dehua Xia , Tri Thanh Pham , Boris Golman , Stavros G. Poulopoulos

Mercury contamination in aqueous media poses a severe environmental and health risk due to its high toxicity and bioaccumulation potential. In this study, a novel thiol-grafted kaolin pellet adsorbent was developed for efficient Hg²⁺ remediation. The pellet production involved a combination of acid-base treatment, 3-mercaptopropyltrimethoxysilane grafting, and extrusion with polyvinyl alcohol serving as a binder. Additionally, a novel approach was developed to assess biofilm formation on the produced pellets. Characterization results confirmed the successful grafting of thiol groups, providing high-affinity binding sites for Hg²⁺ ions. Optimal operating conditions were identified using 2-mm pellets, 1.5 wt% PVA, 5 g/L dosage, and an initial solution pH of 5, achieving 74.2 % removal and adsorption capacities of up to 12.5 mg/g at 313 K. Kinetic studies revealed that Hg²⁺ uptake followed a pseudo-second-order model (R² = 0.986), while isotherm studies indicated the Freundlich model (R² = 0.987, 0.993, and 0.997 for 293, 303, and 313 K, respectively) as the best model. Antibacterial assays demonstrated that raw and acid-base-treated kaolin pellets inhibited biofilm formation for E. coli (BL21), P. aeruginosa, S. epidermidis, and S. aureus, whereas thiol-grafted pellets promoted biofilm development, highlighting the need to balance adsorptive enhancement with potential microbial colonization. These findings confirm the potential of kaolin-based pellet adsorbents for Hg²⁺ remediation, offering a viable framework for scaling up into industrial applications.

水介质中的汞污染由于其高毒性和潜在的生物蓄积性，造成了严重的环境和健康风险。在这项研究中，开发了一种新型的硫醇接枝高岭土颗粒吸附剂，用于高效的Hg2+修复。球团的生产包括酸碱处理、3-巯基丙基三甲氧基硅烷接枝和聚乙烯醇作为粘合剂的挤压。此外，还开发了一种新的方法来评估生产的颗粒上的生物膜形成。表征结果证实了巯基的成功接枝，为Hg2+离子提供了高亲和力的结合位点。确定了最佳操作条件：2 mm球团，1.5 wt% PVA， 5 g/L投加量，初始溶液pH为5，在313 K下达到74.2%的去除率和12.5 mg/g的吸附量。动力学研究表明，Hg2+吸收服从拟二阶模型（R2 = 0.986），等温线研究表明，Freundlich模型（在293、303和313 K下，R2分别= 0.987、0.993和0.997）是最佳模型。抗菌实验表明，未经处理和酸碱处理的高岭土颗粒抑制大肠杆菌（BL21）、铜绿假单胞菌、表皮葡萄球菌和金黄色葡萄球菌的生物膜形成，而硫醇接枝的颗粒则促进了生物膜的形成，强调了平衡吸附增强与潜在微生物定植的必要性。这些发现证实了高岭土颗粒吸附剂修复Hg2+的潜力，为扩大到工业应用提供了可行的框架。

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引用次数: 0

In-situ transformation of a natural Xuyi palygorskite into nano-structured K-Ca-Fe-Mg/SAPO-34 zeolites for enhanced MTO catalytic performance 天然盱眙县坡高岭土原位转化为纳米结构K-Ca-Fe-Mg/SAPO-34分子筛以增强MTO催化性能

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-09-01 DOI: 10.1016/j.clay.2025.107982

Haizhou Tian , Jianghui Tao , Zheng Wang

A nano-structured K-Ca-Fe-Mg/SAPO-34 (MeAPSO-34) composite catalyst was successfully synthesized through the in-situ transformation of palygorskite (Pal) under steam-assisted crystallization conditions. Pal served as a multifunctional precursor, providing inherent Si, Al, Fe, Mg, K, and Ca elements that were directly incorporated into the catalyst framework without the addition of external metal sources. This approach facilitated the formation of hierarchically porous SAPO-34 zeolites with a well-balanced distribution of Brønsted and Lewis acid sites, as confirmed by comprehensive characterization techniques including XRD, SEM, BET, XPS, and NH₃-TPD. Complete methanol conversion was achieved over the MeAPSO-34 zeolite catalyst, with ethylene and propylene selectivities of 69.0 % and 27.4 %, respectively, at a reaction temperature of 410 °C, a methanol-to-water feed ratio of 1:6, and a weight hourly space velocity (WHSV) of 1 h⁻¹. Notably, the synergistic interaction among the K, Ca, Fe, and Mg multi-metallic components significantly promoted the water-gas shift reaction and effectively suppressed coke deposition. Furthermore, the nanostructured morphology of the catalyst reduced the diffusion limitations by shortening the gas-phase transport pathways, thereby enhancing the overall catalytic performance of the SAPO-34 zeolite. This study presents a scalable strategy for designing high-performance methanol-to-olefin (MTO) catalysts through the direct transformation of clay minerals into nanostructured multifunctional materials.

在蒸汽辅助结晶条件下，通过坡菱板矿（Pal）的原位转化，成功合成了一种纳米结构的K-Ca-Fe-Mg/SAPO-34 （MeAPSO-34）复合催化剂。Pal作为多功能前驱体，提供了内在的Si， Al, Fe, Mg， K和Ca元素，这些元素直接结合到催化剂框架中，而无需添加外部金属源。通过XRD、SEM、BET、XPS和NH3-TPD等综合表征技术证实，该方法有助于形成具有Brønsted和Lewis酸位点分布良好的分层多孔SAPO-34分子筛。MeAPSO-34分子筛催化剂在反应温度410℃、甲醇-水进料比1:6、重量-小时空速（WHSV）为1 h−1的条件下，乙烯和丙烯的选择性分别为67.0%和27.4%，实现了甲醇的完全转化。值得注意的是，K、Ca、Fe和Mg多金属组分之间的协同作用显著促进了水煤气转移反应，有效抑制了焦炭沉积。此外，催化剂的纳米结构形态通过缩短气相传输途径减少了扩散限制，从而提高了SAPO-34沸石的整体催化性能。本研究提出了一种可扩展的策略，通过将粘土矿物直接转化为纳米结构多功能材料来设计高性能的甲醇制烯烃（MTO）催化剂。

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引用次数: 0

A physics-based CatBoost model for water retention of compacted bentonite with global sensitivity analysis 基于物理的膨润土保水性CatBoost模型及全局敏感性分析

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2025-08-30 DOI: 10.1016/j.clay.2025.107948

Muntasir Shehab , Reza Taherdangkoo , Christoph Butscher

Bentonite is a recommended buffer material in high-level radioactive waste repositories to restrict the migration of radionuclides into the environment. Determining the soil water retention curve (SWRC) of bentonite is essential for predicting its hydraulic behaviour, including water flow dynamics and saturation time, which are critical for evaluating the performance of engineered barrier systems. This study compiled 46 experimental SWRCs from existing literature containing 311 data points of matric potential and corresponding water content. Key soil properties associated with these data points include specific gravity, montmorillonite content, initial dry density, initial water content, initial void ratio, and plasticity index. The Van Genuchten model parameters were optimized using the Levenberg–Marquardt algorithm for each of the 46 SWRCs. To enrich the SWRC data, 20 additional data points of matric potential were generated, and the predicted water content from the optimized Van Genuchten models was then combined with the experimental data. A machine learning model was developed to predict the SWRC of bentonite using the CatBoost machine learning algorithm; and fine-tuned its hyper-parameters using the artificial gorilla troops optimizer. As input, the machine learning model used matric potential, key soil properties, and experimental conditions such as confined or unconfined states and drying or wetting paths. The machine learning model shows very good performance in estimating the water content at various matric potentials, offering an efficient method to determine the SWRC of bentonite based on key soil properties.

膨润土是高放射性废物贮存库中推荐的缓冲材料，以限制放射性核素向环境中的迁移。确定膨润土的土壤保水曲线（SWRC）对于预测其水力特性至关重要，包括水流动力学和饱和时间，这对于评估工程屏障系统的性能至关重要。本研究从现有文献中整理了46个实验swrc，包含311个数据点的基质电位和相应的含水量。与这些数据点相关的关键土壤特性包括比重、蒙脱土含量、初始干密度、初始含水量、初始孔隙比和塑性指数。采用Levenberg-Marquardt算法对46个SWRCs的Van Genuchten模型参数进行了优化。为了丰富SWRC数据，增加了20个矩阵电位数据点，并将优化后的Van Genuchten模型预测的含水率与实验数据相结合。利用CatBoost机器学习算法建立了预测膨润土SWRC的机器学习模型；并使用人工大猩猩部队优化器对其超参数进行微调。作为输入，机器学习模型使用了基质电位、关键土壤特性和实验条件，如受限或无受限状态以及干燥或湿润路径。机器学习模型在估算不同基质电位下的含水量方面表现出很好的性能，为基于关键土壤性质确定膨润土的SWRC提供了一种有效的方法。

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