Article
Chemistry, Physical
D. A. Dixon, J. Stone, K. Birch, C. S. Kim
Summary: The NWMO is evaluating Sedimentary and Crystalline geosphere media for a potential Deep Geological Repository (DGR) for nuclear waste. They tested bentonite-aggregate mixtures with different compositions and observed the effect of compaction efforts on densification. The results showed that the materials met the required performance goals for swelling pressure and hydraulic conductivity.
APPLIED CLAY SCIENCE
(2023)
Article
Engineering, Geological
Yong-Gui Chen, Ye-Qing Cai, Kan Pan, Wei-Min Ye, Qiong Wang
Summary: The study found that for mixtures with low sand content, swelling pressure is only related to bentonite dry density, while hydraulic conductivity is influenced by the presence of sand particles. Exponential relationships exist among final swelling pressure, saturated hydraulic conductivity, and bentonite dry density, with infiltrating salt solutions leading to higher swelling pressure and lower hydraulic conductivity. High swelling pressure and low hydraulic conductivity in specimens infiltrated with calcium chloride solutions are attributed to cation exchange reactions and competition between calcium ions in smectite interlayers and electrolyte solutions.
Article
Construction & Building Technology
Yong-Gui Chen, Xiao-Xiao Zhang, Xue-Min Liu, Wei-Min Ye, Qiong Wang
Summary: This study investigates the effect of graphene content and dry density on the swelling properties of graphene-modified bentonite. The results show that the swelling pressure and pore distribution are significantly influenced by the graphene content and dry density. The findings provide valuable insights into the design of buffer materials for deep geological disposal.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Nuclear Science & Technology
Minseop Kim, Seungrae Lee, Jinseop Kim, Seok Yoon
Summary: This study investigates the influence of the initial dry density and water content on the swelling pressure and consolidation characteristics of Korean bentonite. The findings indicate that the influence of these factors on swelling pressure is not absolute and can show different tendencies depending on the case, while the consolidation behavior is affected by dry density and temperature.
PROGRESS IN NUCLEAR ENERGY
(2023)
Article
Engineering, Geological
Zhixiong Zeng, Yu-Jun Cui, Jean Talandier
Summary: The study investigated the swelling pressure of compacted bentonite/sand mixtures under constant-volume conditions, finding that the pressure is strongly dependent on bentonite fraction and dry density. Samples with higher bentonite fractions had a linear relationship between swelling pressure and dry density, while lower fractions led to skeletonized sand particles and heterogeneous distribution of montmorillonite, resulting in larger swelling pressures. The study used maximum sand skeleton void ratio to estimate critical dry density and bentonite fraction, finding good agreement between test data and estimated results.
Article
Engineering, Geological
D. A. Dixon, J. Stone, K. Birch, C. S. Kim
Summary: Several countries, including Canada's NWMO, are planning to safely isolate used nuclear fuel deep underground. The sealing systems, using bentonite-based materials, need to have low hydraulic conductivity and the ability to swell when in contact with groundwater. Data and ongoing studies show the relationship between dry density, swelling pressure, and hydraulic conductivity under different porefluid compositions.
CANADIAN GEOTECHNICAL JOURNAL
(2023)
Article
Engineering, Geological
D. A. Dixon, J. Stone, K. Birch, C. S. Kim
Summary: Several countries plan to safely store used nuclear fuel underground in deep geologic repositories. Canada's NWMO suggests using corrosion-resistant containers and bentonite-based sealing systems to ensure low hydraulic conductivity and swelling ability when in contact with groundwater. Data from studies on bentonite behavior are evaluated to determine the best-fit relationships between density, swelling pressure, and hydraulic conductivity under different pore fluid conditions.
CANADIAN GEOTECHNICAL JOURNAL
(2023)
Article
Engineering, Environmental
Pu-huai Lu, Yong He, Wei-min Ye, Yong-gui Chen, Ke-neng Zhang
Summary: This study investigates the effects of water seepage on the hydro-mechanical performance of compacted bentonite. It is found that the swelling pressure decreases with increasing salt concentration in the seepage water or decreasing initial dry density. The relationship between swelling pressure and time is fitted with empirical kinetic equations. Microscopic analysis indicates that the reduction in swelling pressure can be attributed to osmotic consolidation, ionic exchange, and mineral dissolution of bentonite.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Engineering, Geological
Yu Lu, Wei-Min Ye, Qiong Wang, Yong-Gui Chen
Summary: In this article, the swelling pressures of GMZ bentonite specimens prepared in different ways were studied under static compaction. The results confirmed the existence of residual lateral stress and sidewall friction. The swelling pressure parallel to the compaction direction was higher than that perpendicular to the compaction axis, and its anisotropy coefficient decreased to a certain degree upon hydration. The initial suction effects on the anisotropy coefficient depended on hydration, and the swelling pressure significantly increased with increasing dry density, with a 9.6-times increase as the density increased from 1.5 to 1.9 Mg/m³. The anisotropy coefficient of swelling pressure increased at first and then slightly decreased with increasing dry density.
Article
Environmental Sciences
Virginia Cabrera, Ruben Lopez-Vizcaino, Vicente Navarro, Angel Yustres
Summary: This paper presents a database of thermo-hydro-chemo-mechanical tests on bentonites, named Bento_DB4THCM. The database includes a comprehensive collection of experimental tests for validation exercises of numerical codes simulating the behavior of bentonites. The tests cover a wide range of clays, and the results are from different swelling and squeezing tests. The database is provided as Supplementary material.
ENVIRONMENTAL EARTH SCIENCES
(2023)
Article
Chemistry, Physical
K. A. Daniels, C. C. Graham, A. C. Wiseall, J. F. Harrington, P. Sellin
Summary: Geological storage with clay buffer is widely preferred for removing hazardous radioactive waste. The impact of fluid salinity and void space on the swelling behavior of barrier bentonites was examined through experiments. The findings suggest that clay swelling is suppressed at higher salinities, which affects the void-filling process.
APPLIED CLAY SCIENCE
(2024)
Article
Engineering, Environmental
Yu Lu, Wei-Min Ye, Qiong Wang, Yuan-Hong Zhu, Yong-Gui Chen, Bao Chen
Summary: The study found that bentonite exhibits anisotropic swelling behavior during static compaction, with significantly higher swelling strain along the perpendicular direction compared to the parallel direction. Increasing initial dry density results in higher swelling time, strain, and rate, while increasing vertical pressure decreases these parameters. The anisotropy coefficient initially increases and then stabilizes, with final anisotropy coefficient being influenced by initial dry density and vertical pressure.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Chemistry, Physical
Fabien Bernachy-Barbe
Summary: The study focuses on understanding the coupled processes of swelling and water transport in bentonite at the laboratory scale. Through detailed X-ray microtomography measurements of samples saturated under isochoric conditions, the study reveals the complex evolution of water and clay transport, permeability, mechanical properties, and friction properties. The research highlights the significant impact of initial density heterogeneities on the saturation process and the final state of the samples, as well as the role of wall friction in hydration kinetics.
APPLIED CLAY SCIENCE
(2021)
Article
Chemistry, Physical
Jongmuk Won, Jang-Un Kim, Hyunwook Choo
Summary: In this study, the electrical conductivity of compacted bentonite was measured under different conditions to investigate its predictability for swelling strain or swelling pressure. The results showed that monitoring electrical conductivity could detect the initiation and termination of swelling process and internal changes. Relationships between normalized swelling parameters and electrical conductivity were established and verified. The limitations and possibilities of using electrical conductivity for estimating swelling parameters and monitoring swelling process were discussed.
APPLIED CLAY SCIENCE
(2023)
Article
Engineering, Geological
Zhixiong Zeng, Yu-Jun Cui, Jean Talandier
Summary: The study examined the compaction properties of bentonite/claystone mixtures with varying bentonite fractions and water contents to establish a suitable fabrication protocol for compacted blocks. Results showed that as bentonite fraction increased, overall compressibility decreased, while compressibility at lower vertical stress increased with higher water content. Higher water content led to reduced swelling pressure and hydraulic conductivity due to increased intercalated water and decreased inter-aggregate pore volume.
ENGINEERING GEOLOGY
(2021)
Article
Chemistry, Physical
Nadine J. Kanik, Artur Kuligiewicz, Jeffrey T. Cullen
Summary: This study examined the effects of different pre-treatments on the structural H-isotope composition of clay minerals. The results showed that different pre-treatments had varied impacts on different clay minerals, and the choice of pre-treatment should be based on the specific properties and mineralogy of the samples.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Lorenzo Lisuzzo, Giuseppe Cavallaro, Stefana Milioto, Giuseppe Lazzara
Summary: This study proposes Pickering emulsions based on wax and halloysite clay nanotubes for coating silk sutures to increase their loading capacity towards eosin. The presence of halloysite/wax microspheres on the surface of silk sutures has also been explored for controlled release of hydrophobic drugs. The influence of the coating on the thermal and mechanical properties of the sutures has been studied using various techniques. In conclusion, the wax/halloysite Pickering emulsions can successfully generate hydrophobic microdomains on the surface of silk sutures, leading to enhanced flexibility and improved loading capacity towards eosin.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Bruna F. Alves, Rita C. P. Nunes, Luiz C. Bertolino, Elizabete F. Lucas
Summary: Operational problems in the oil industry caused by the precipitation of paraffins can be prevented by using polymeric additives. This article evaluates the use of polymeric nanocomposites as pour point reducers in different types of crude oil and finds that they are more efficient than pure poly(ethylene-covinyl acetate) (EVA) in reducing the pour point. The nanocomposites also modify the wax crystals and reduce the viscosity of the oil samples.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
K. A. Daniels, C. C. Graham, A. C. Wiseall, J. F. Harrington, P. Sellin
Summary: Geological storage with clay buffer is widely preferred for removing hazardous radioactive waste. The impact of fluid salinity and void space on the swelling behavior of barrier bentonites was examined through experiments. The findings suggest that clay swelling is suppressed at higher salinities, which affects the void-filling process.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
N. Werling, A. Kuligiewicz, A. Steudel, R. Schuhmann, F. Dehn, K. Emmerich
Summary: Thermal treatment of clay minerals can be used to produce building materials and environmentally friendly binders. This process involves dehydration, dehydroxylation, breakdown of structure, and recrystallization of high temperature phases. Rehydration and rehydroxylation are important factors to consider for geopolymers and SCM.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Xuan Wang, Hao Ding, Zhuoqun Xu, Jianmeng Zhang, Yanbin Yao
Summary: Rutile nano-TiO2 was loaded onto the surface of sericite to prepare sericite-rutile composite particles, which were then modified with HDTMS and sprayed onto the substrates to form sericite-rutile/HDTMS composite coatings with UV shielding and superhydrophobic self-cleaning properties. The coating exhibited good UV shielding rate and remained superhydrophobic after UV irradiation. The hierarchical structure of the sericite-rutile composite and the low surface energy of HDTMS contributed to the superhydrophobicity and UV shielding effect of the coating.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Kailang Sun, Taojun Zhang, Jie Zhou, Yonghong Liu, Minfeng Zeng, Zhen Yang, Ruokun Feng, Xiaorong Ren, Peng Zhang, Baoyi Wang, Xingzhong Cao
Summary: Chitosan-Pd0 nano particles encapsulated in Al, Co-pillared montmorillonite nanocomposites were successfully synthesized using a facile one-pot heat treatment method. The Al, Co pillaring effectively expanded the surface area and generated numerous mesopores in the interlayer space of the MMt. The resultant nanocomposite exhibited similar high comprehensive catalytic performances as the one prepared by the regular divided-multistep method. The encapsulation of CS chains and doping of Co in the Al pillaring also contributed to the improved catalytic performance.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Nathalie Fagel, Isabel Israde-Alcantara, Reza Safaierad, Marttiina Rantala, Sabine Schmidt, Gilles Lepoint, Pierre Pellenard, Nadine Mattielli, Sarah Metcalfe
Summary: Environmental conditions significantly influence clay minerals, and studying clay sediments in tropical lakes can provide valuable insights into past environmental conditions. In this study, multiproxy records from sediment cores of three crater lakes in central Mexico were analyzed. The results showed that disordered kaolinite, formed through hydrolysis and hydrothermal alteration, was the predominant mineral in the sediments. The abundance of kaolinite varied in relation to organic carbon and organic matter-related elements, and showed opposite trends with lithogenic elements. Geochemical data suggested that the increase in kaolinite abundance is linked to the formation of organo-mineral aggregates and lake level changes in closed basins.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
M. J. Martin-Alfonso, A. Mejia, F. J. Martinez-Boza, P. Partal
Summary: The drilling industry is facing new challenges to develop eco-friendlier drilling fluids. Organic modified sepiolite dispersed in oil can be an excellent additive with suitable rheological properties. This study investigated the effect of alkyl ammonium modifiers on the microstructure and rheological properties of sepiolite-vegetable oil dispersions under high-temperature and high-pressure conditions.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Weiquan Zhan, Siyuan Yang, Shenxu Bao, Liuyi Ren, Cheng Liu
Summary: The interaction between talc and the depressor CMC was investigated through molecular dynamics simulation and density functional theory calculation. It was found that CMC showed stronger adsorption on the edge plane of talc due to enhanced interactions with polar groups and water molecules. The study also revealed specific interactions between H atoms in CMC and O atoms in the edge plane, as well as between O atoms in CMC and Si, Mg atoms in the edge plane. Hydration shells on the basal and edge planes of talc were examined to explain the phenomenon.
APPLIED CLAY SCIENCE
(2024)
Article
Chemistry, Physical
Pierre Dramou, Yiyang Sun, Xu Ni, Fangqi Wang, Hua He
Summary: In this study, a magnetic nanocomposite was prepared and used for the separation of rutin from real samples through magnetic solid phase extraction (MSPE). The nanocomposite exhibited high specific surface area, chemical and thermal stability, water solubility, and easy separation in aqueous solution. Characterization and experiments confirmed the successful synthesis and efficient enrichment ability of the nanocomposite.
APPLIED CLAY SCIENCE
(2024)