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Iron (Fe) is an essential micronutrient that affects biological production. Iron-containing clay minerals are an important source of bioavailable iron. However, the dissolution of iron-containing clay minerals at temperatures below the freezing point has not been investigated. Here, we demonstrate the enhanced reductive dissolution of iron from a clay mineral in ice in the presence of iodide (I) as the electron donor. The accelerated production of dissolved iron in the frozen state was irreversible, and the freeze concentration effect was considered the main driving force. Furthermore, the formation of magnetite (FeO) after the freezing process was observed using transmission electron microscopy analysis. Our results suggest a new mechanism of accelerated abiotic reduction of Fe(III) in clay minerals, which may release bioavailable iron, Fe(II), and reactive iodine species into the natural environment. We also propose a novel process for magnetite formation in ice. The freezing process can serve as a source of bioavailable iron or act as a sink, leading to the formation of magnetite.
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http://dx.doi.org/10.1021/acs.est.3c06144 | DOI Listing |
PLoS One
September 2025
Daqing Yongzhu Petroleum Technology Development Co Ltd., Daqing, China.
Background: Strongly water-sensitive reservoirs with high clay content face challenges in conventional development due to clay swelling and impeded seepage. CO2 injection shows potential for enhanced oil recovery (EOR) and carbon sequestration; however, the role of clay minerals in regulating CO2-induced asphaltene deposition and sequestration remains unclear.
Methodology: We conducted experiments on clay-oil interactions, nuclear magnetic resonance (NMR), measurements of crude oil properties, and long core water flooding tests to evaluate deposition, reservoir damage, and CO2 sequestration.
Biomacromolecules
September 2025
Department of Chemical Engineering, CERES, University of Coimbra, Rua Sílvio Lima, Pólo II, 3030-790 Coimbra, Portugal.
Cellulose nanofibrils (CNFs) produced via deep eutectic solvent (DES) pretreatment were used, for the first time, to prepare composite films/nanopapers with fibrous clays (sepiolite and palygorskite). Highly transparent films containing up to 50% clay were successfully obtained, avoiding energy-intensive homogenization processes and clay chemical modifications, with absolute transparency losses relative to the transparency of the neat CNF film of ∼15% for 50% sepiolite. Higher transparency losses were found for TEMPO-oxidized CNF and cationic CNF composite films prepared for comparison purposes.
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August 2025
Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia.
The unconfined compressive strength of organic-rich clay shale is a fundamental parameter in geotechnical and energy applications, influencing drilling efficiency, wellbore stability, and excavation design. This study presents machine learning-based predictive models for unconfined compressive strength estimation, trained on a comprehensive dataset of 1217 samples that integrate non-destructive indicators such as ultrasonic pulse velocity, shale fabric metrics, wettability potential and destructive field-derived parameters. A dual-model framework was implemented using Support Vector Machine, Decision Tree, K-Nearest Neighbor, and Extreme Gradient Boosting (XGBoost) algorithms.
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August 2025
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China.
To mitigate the adverse ecological impacts of inorganic solidified materials on modified red clay and address the issues of low bearing capacity and extensive cracking under hydraulic erosion, this study investigates the use of low-environmental-impact materials to improve the mechanical fracturing of red clay. In this context, this study focuses on modifying red clay using an environmentally friendly biopolymer, xanthan gum (XG). Through a series of laboratory mechanical and microstructural tests, the effects of XG on the mechanical fracturing, California Bearing Ratio (CBR), and microstructural characteristics of red clay are examined.
View Article and Find Full Text PDFNPJ Microgravity
August 2025
Advanced Ceramics, University of Bremen, Bremen, Germany.
The long-term goal of establishing a sustained human presence on Mars requires the capacity to produce essential consumables on-site. To this end, we develop strategies for processing inorganic oxidic powders and biomass into highly particle-filled composites using direct ink writing (DIW) 3D printing. Our approach relies on a simulant of a Martian regolith unit rich in hydrated clay minerals and food-grade spirulina, used as proxies for local regolith and cyanobacterial biomass, respectively.
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