Distribution of plutonium in a ternary system of water-colloid-bentonite: Implications for radionuclide migration.

Study on microstructure and permeability of modified cut-off wall materials under chemical environmental effects.

The increasing presence of microplastics (MPs) in aqueous matrices has driven the search for efficient and sustainable technologies for their removal. In this context, this work investigates the development of green polymeric membranes based on poly-(vinyl alcohol) (PVA) reinforced with bentonite clay nanoparticles (ArNPben), aiming to establish relationships between structure, properties, and performance in microplastic filtration. The membranes were produced by the solvent evaporation phase inversion method, employing PVA at different concentrations (6-10% w/v), citric acid as a cross-linking agent, and glycerol as a plasticizer, with the incorporation of bentonite (1-5% w/w). Characterization was performed using morphological, spectroscopic, and thermal techniques (SEM, FTIR, TGA, and DSC), associated with the evaluation of transport behavior and retention efficiency. The results demonstrated that the controlled incorporation of bentonite promotes structural reorganization of the polymer matrix, directly affecting hydraulic permeability, stability, and interaction with particles. A critical dispersion limit of the inorganic phase was observed, where low concentrations favor the formation of homogeneous and functionally efficient structures, while higher concentrations induce structural heterogeneity and increased resistance to transport. The formulation containing 6% (w/v) PVA and 1% (w/w) bentonite showed the best overall performance, combining structural stability and permeation capacity, achieving an average PM removal efficiency of 99.78 ± 0.13% in tests conducted under controlled pressure. Evidence obtained by FTIR and TGA confirmed the retention of polymeric material on the surface of the membranes after use. The results highlight the potential of the developed hybrid membranes as a sustainable and technically viable alternative for application in water treatment systems contaminated by microplastics, contributing to the advancement of technologies based on materials with low environmental impact.

Passivation is a feasible approach for remediating heavy metal-contaminated soil. However, how passivation stability depends on material type, dosage, and plant cultivar remains unclear. Phosphate rock powder (PR) and bentonite (BN) were applied for passivation at three dosages, and the passivation activity was evaluated on high- and low-Cd-accumulating wheat cultivars. Phosphate rock powder (PR) and BN decreased the available Cd content in the soil by 11.52-26.65% and 11.08-35.00%, and in the wheat grains by 7.28-49.94% and 14.14-57.61%, respectively. PR3 and BN3 enhanced wheat yield by 12.77-21.31% and 12.23-18.67%, respectively. The passivation activity of both materials increased with increasing dosage. The optimal ranges for effective, stable Cd passivation were 0.29-0.61 and 3.85-8.46 t ha-1 for PR and BN, respectively. Path analysis revealed that PR acts mainly through increases in soil available phosphorus and associated changes in Cd fractions, whereas BN acts primarily through the soil cation exchange capacity; grain Cd was chiefly associated with reactive Cd fractions. The different Cd accumulation capacities of wheat cultivars affected the passivation effects of PR and BN. The soil of Jimai22 showed significantly lower EXC-Cd and Carb-Cd and significantly higher FeMnOz-Cd than Zhoumai18. Moreover, soil pH was higher for Jimai22 than for Zhoumai18. These results suggest that combining the selection of suitable passivation materials, optimising the dosage and planting low-Cd-accumulating cultivars is an effective strategy for maintaining Cd passivation in weakly alkaline soils.

Lewis acidic bentonite catalysts enable rapid (<10 min) and quantitative removal of 5'-O-dimethoxytrityl (DMTr) and 5'-O-(2-methoxypropyl) hydroxyl protecting groups. These catalysts selectively deprotect the 5'-OH of protected nucleosides in the presence of standard therapeutic oligonucleotide modifications. Similarly fast and quantitative deprotection of nucleotide dimers was observed, highlighting this method as an attractive option for simplified liquid phase oligonucleotide synthesis (LPOS).

Adsorption and detoxification of ochratoxin A using hydrophobic bentonite clay.

Effect of sintering temperature on the performance of Co₃O₄-coated bentonite clay based interfacial solar evaporators: A sustainable solution for desalination

The rising growth of agricultural waste poses significant challenges to environmental sustainability, community health, and commercial stability. However, the development of multifunctional bio-based additives that simultaneously provide reinforcement and antioxidant performance in natural rubber (NR) composites remains limited. This study examines the potential of an aluminum (lignin/silica/fatty acid) hybrid (Al(LSF)), derived from rice straw black liquor, as a dual-functional additive with reinforcing and antioxidant properties in natural rubber (NR) composites. The Al(LSF) hybrid was analyzed by XRF, SEM-EDX, TEM, particle size analysis, and zeta potential measurements. Morphology, curing behavior, mechanical properties, and thermo-oxidative aging resistance of Al(LSF) in NR matrices were also investigated. Results showed that Al(LSF) exhibited nanoscale characteristics enabling uniform dispersion in the NR matrix. The incorporation of Al(LSF) (1–4 phr) improved curing properties, as evident by the decreased optimum curing time by approximately 18.3% as compared to TMQ/NR composites. Tensile strength of NR composites increased by approximately 45.4%, and elongation at break reduced by approximately 26.4% at 1 phr loading of Al(LSF) hybrid. The improvement in thermo-oxidative aging resistance of NR composites with Al(LSF) could be observed from th increased aging coefficient from 0.43 to 0.55 (approximately 27.9%). NR composites reinforced with Al(LSF) displayed better mechanical strength and aging properties than those filled with conventional fillers such as silica and sodium bentonite, depending on hybrid loading. Al(LSF)/NR composites can be explored for applications requiring improved long-term thermo-oxidative aging resistance and mechanical strength, such as tires, conveyor belts, gaskets, shoe soles, and other rubber products used outdoors exposed to extreme environmental conditions. Therefore, Al(LSF) hybrid could be considered as a potential multifunctional bio-additive to enhance mechanical strength and thermo-oxidative stability of NR while valorizing agricultural waste.

Abstract Accurate, low-cost measurement of volumetric water moisture (VWC) is needed for environmental monitoring and hydrology, yet many microwave methods require two-port fixtures or invasive sampling. A compact one-port UHF sensor based on a short-circuited Goubau line (G-line) with complementary split-ring resonator (CSRR) loading is reporyed for soil moisture assessments. The sensing mechanism is absorption at a reflection-dip in reflection coefficient, whose resonant frequency shifts with soil permittivity. A dispersion analysis motivates operation in the \SIrange{0.65}{0.75}{GHz} range, where temperature dependence of soil permittivity is moderate. The sensor is realized as a microstrip-fed G-line with a via short and CSRR inductive loading; measurements are performed using a controlled sample holder. The method is validated on four soils (Ottawa sand, bentonite, marl, and red clay), yielding linear regressions between the dip frequency $F$ (MHz) and volumetric water content (VWC, \%) with $R^2 = 0.929$--$0.984$. The sensitivity ranges from 1.81--2.19~MHz/\%VWC, and the limit of detection (three-run repeatability, $3.3\sigma$) is 0.21~\%VWC. The results demonstrate a traceable, one-port route to VWC estimation using a low-complexity G-line probe suited to integration in environmental sensing systems.

Summary Wellbore instability remains a persistent and complex challenge in drilling engineering, posing significant threats to operational safety and efficiency, particularly when employing water-based drilling fluids (WBDFs). Conventional mitigation strategies often rely on mechanical/chemical coupling approaches that adjust fluid density and incorporate chemical stabilizers or plugging agents; however, their effectiveness diminishes under extreme downhole conditions. To address this limitation, we propose a novel biological wellbore stabilization method that integrates a heat- and drilling-fluid-resistant bacterium (SY113T) capable of microbially-induced calcium carbonate (CaCO3) precipitation. The SY113T strain was isolated, cultivated, and systematically evaluated for its adaptability and stabilization performance under simulated drilling conditions. Morphologically, SY113T exhibits cell dimensions of 0.8–2.4 µm and demonstrates exceptional thermal tolerance, maintaining vigorous growth at temperatures up to 120°C and within a pH range of 8–10, even in the presence of drilling fluid treatment agents. Under urea concentrations of 1–6% and calcium ion (Ca²+) concentrations of 0.5–4%, the bacteria metabolically produced urease exhibits high catalytic activity, enabling efficient microbially-induced CaCO3 precipitation reactions. Artificial cores immersed in sodium bentonite (Na-Bent) slurry containing SY113T and its culture medium exhibited a 28.5% increase in uniaxial compressive strength (UCS) compared with those soaked in pure water, and a 22.6% improvement over samples treated with conventional chemical stabilizers. Building upon these findings, a microbial wellbore-stabilizing WBDF formulation was developed through optimized chemical additive selection and the incorporation of SY113T, forming a synergistic mechanical/chemical/biological stabilization system. Rheological tests confirmed that SY113T and its culture medium exert negligible influence on fluid rheology while simultaneously reducing filtration loss and linear expansion. Mechanical evaluations further revealed that both artificial and field cores treated with the microbial WBDF demonstrated remarkable UCS enhancements of 46.2% and 81.2%, respectively, relative to pure water, and exceeded those achieved by conventional inhibitory drilling fluid systems by 24.9% and 17.0%, respectively. The experimental results demonstrate that the SY113T strain exhibits remarkable adaptability and mineralization activity under simulated downhole harsh conditions, offering a biological solution with significant potential for enhancing wellbore stability.

Life cycle assessment as a tool for eco-design of modified materials for water treatment

This study addresses the critical challenge of sustainable wastewater treatment by investigating and valorizing agro-industrial residues as high-performance, zero-waste coagulants. The scope of this engineering investigation was the optimization and comparative assessment of 4 readily available materials – bentonite (BN), eucalyptus leaf powder (ELP), agave powder (AP), and the novel nopal fibrous residue powder (NFRP) – as alternatives to aluminium sulphate (AS) for urban wastewater treatment. The core novelty and innovation lie in the successful utilization of the discarded fibrous residue of the nopal cactus; this approach fundamentally shifts the paradigm from complex, resource-intensive extraction of nopal mucilage to the direct, simple use of a high-volume waste product. This leverages the lignin- and tannin-rich components, which are shown to be responsible for bio-flocculation, making the process intrinsically simpler, cheaper, and scalable, relative to state-of-the-art mucilage-based technologies. The statistical analysis confirmed significant differences in pollutant removal based on the material (p &lt; 0.01). Agave powder (AP) was statistically superior for clarity, achieving a maximum turbidity removal percentage (TRP) of 97.76 ± 2.180% at an optimal dose of 20 mg/L, statistically outperforming AS. Conversely, for the removal of organic pollutants, the chemical standard AS was superior in single-dose trials, with COD reduction (CODR) ≈ 88.5%. However, the synergistic combination of NFRP (100 mg/L) and BN (60 mg/L) achieved the highest CODR ≈ 92.13 ± 0.398%, successfully exceeding the performance of AS. Furthermore, AP demonstrated high effectiveness in ammoniacal nitrogen removal (≈ 75%), highlighting its multi-pollutant capacity.

Sulfonamide antibiotic residues in milk are considered highly dangerous to human health and food safety due to their persistence and potential for bioaccumulation. Conventional removal methods were often costly and inefficient, highlighting the need for sustainable and effective alternatives. The study aimed to assess the efficiency of organically modified bentonite clay (OMB-16) in the removal of sulfonamide antibiotics (sulfadimidine sodium, sulfadiazine, and sulfaguanidine) from milk and to optimize the conditions to achieve maximum adsorption capacity. The extraction efficiency of OMB-16 was evaluated in comparison with unmodified bentonite, and key parametersm including solution pH, adsorbent loading, and elution solvent—were optimized. Quantification was performed using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV), which demonstrated that OMB-16 exhibited better extraction performance than untreated bentonite. The recovery percentages using OMB-16 reached 90% for sulfadimidine and sulfadiazine, which were higher than the 80% and 75% recoveries obtained using unmodified bentonite, respectively. The best results were achieved at a mildly acidic pH of 4–5, while methanol was identified as the most efficient desorption solvent. The intra- and inter-day precision of the OMB-16 method was also evaluated, and the results confirmed that the method was reproducible. It was further observed that the HPLC-UV method was sensitive and specific, demonstrating good linearity (R² ≥ 0.99) and low limits of detection. Overall, this study showed that OMB-16 was an effective and reliable adsorbent for removing pharmaceutical residues from complex food matrices such as milk, with potential applications in food safety monitoring and residue analysis.

Ca2+-rich brines strongly destabilize bentonite-based drilling fluids by weakening hydration and increasing filter-cake permeability. In this work, raw sodium bentonite (Na-Bt) and a series of cation-exchanged bentonites (Li-, Mg-, Ca-, and K-Bt) were comparatively investigated to clarify how cation-dependent hydration characteristics and interlayer structure govern filtration behavior under saline conditions. XRD, zeta potential, TG-DTG, BET, and SEM were employed to correlate basal spacing, surface electrostatic properties, thermal/water-loss behavior, surface area and pore-structure characteristics, and filter-cake microstructure with API fluid loss. Among the examined 2 wt% brines, CaCl2 produced the most severe deterioration and was therefore selected as the representative screening condition. Under 2 wt% CaCl2, Li-Bt exhibited the lowest FLAPI (141 mL), which was substantially lower than that of Na-Bt (265 mL), indicating the most favorable intrinsic resistance to Ca2+-dominated salinity. The cation-exchange analysis further showed that Li-Bt and Mg-Bt had relatively higher calculated exchange degrees than Ca-Bt and K-Bt under the present preparation conditions. Based on the 2 wt% CaCl2 dataset, a descriptor-based relation between FLAPI, hydrated ionic radius (rh), and basal spacing (d001) was established, and an Al-modified bentonite provided an out-of-sample verification with close agreement between predicted and measured filtration loss. Additional tests in 1-3 wt% CaCl2 showed that although absolute fluid loss increased with brine severity, the relative ranking of the cation-exchanged bentonites remained broadly unchanged. TG-DTG, BET, and SEM results further provided complementary evidence for the structural and microstructural differences among the samples. Overall, the results demonstrate that hydration-related response, interlayer structure, and surface/pore characteristics jointly govern the filtration behavior of cation-exchanged bentonites, providing a useful basis for screening salt-tolerant clay materials for Ca2+-rich brines.

ABSTRACT Coal-derived char has shown improving the geotechnical performance of cement-stabilized soils. This study aimed to assess the effects of coal char on the hydraulic and durability characteristics of a soil mixture composed of equal sodium bentonite and sand, stabilized with 20% cement. The addition of coal char enhanced both hydraulic and durability properties of the cement-stabilized soil. The inclusion of coal char in cement-stabilized soil further reduced the saturated hydraulic conductivity (Ksat) up to 38%, suggesting decreased water infiltration and greater soil compaction. The soil freezing characteristic curve (SFCC) showed that adding char to cement-stabilized soil samples retained more unfrozen water after 12 freeze-thaw (FT) cycles, which can reduce frost heave for better freeze–thaw resistance. Soil water characteristic curve (SWCC) results demonstrated that char addition improved moisture retention at low suction levels, which could prolong hydration, reduce shrinkage & cracking, and improve drought resilience in arid environments.

Due to the negative carbon footprint of cement production and the decreasing availability of commonly used supplementary cementitious materials (SCM), the thermal activation of non-kaolinite clays for use as pozzolanas was investigated. The calcination potential of two bentonites was studied and compared with the performance of kaolin clay in terms of density, specific surface area, granulometry, thermal analysis, and chemical and phase compositions. Based on thermal analysis, the clays were calcined at 500°C, 550°C, 600°C and 650°C (for three hours) with a heating rate of 10°C min −1 . Then, blended pastes were prepared with the studied clays with a substitution rate of 10% of Portland cement. The pozzolanic activity of prepared pastes was investigated by isothermal calorimetry, lime saturation test (LST), changes in mechanical properties and pH activity test. Tests performed on raw clays revealed the following findings: i) temperatures needed for activation were above 550°C; ii) during firing, the bentonitic clays tend to agglomerate, which, however, can be fixed by additional milling. Results of testing on blended cements can be summarised as follows: iii) all activation temperatures show good potential for thermal activation of bentonites in terms of isothermal calorimetry; iv) lime saturation test showed a slower onset of pozzolanic reaction for bentonites compared to kaolin; v) best mechanical properties were achieved for clays heated to 600°C. • The activation of bentonites was successful for temperatures above 550°C. • Bentonitic clays tend to agglomerate during thermal activation. • Hydration heat curves of bentonitic clays overlapped for all studied temperatures. • Ca(OH) 2 consumption by bentonite clays was initially slower but later accelerated. • Best values of mechanical properties of bentonitic clay pastes were found for 600°C.

Geosynthetic clay liners (GCLs) containing sodium bentonite (NaB) exhibit semipermeable membrane behavior. However, experimental studies to date have evaluated the existence and significance of membrane behavior only of virgin GCLs, and there is no evidence of the persistence of the phenomenon in the field. In this study, membrane behavior was measured for GCL specimens exhumed from a landfill site. The specimens were obtained from a bottom liner system that was left exposed without placement of overlying waste for over a decade. Multistage membrane behavior tests were performed with potassium chloride (KCl) solutions ranging in concentration from 5 to 50 mM to allow for comparison with the literature on membrane behavior of virgin GCLs and NaB. The results showed that membrane behavior persisted in the exhumed GCLs. However, membrane efficiency coefficients (ω) for the exhumed GCLs were <8%, which is substantially lower than ω values typically reported for virgin GCLs. The low ω values for the exhumed GCLs were attributed to cation exchange and downslope bentonite erosion that occurred in the field, as supported by measurements of exchangeable cations, swell index, and mass per unit area. Hydraulic conductivity to water also was determined to be a useful indicator of expected ω values. This study is the first experimental investigation of the persistence of membrane behavior in GCLs after field exposure. The results emphasize the sensitivity of ω to changes in bentonite exchange complex and porosity, and that caution should be exercised when using literature data for virgin GCLs to model long-term barrier performance in the field.

The article presents a method of purification of obtaining betonies clay for use in catalysis. It was found that the cleaning process includes the stages of centrifugation, drying and mechanical activation. Clay cleaning frees it from impurities and increases the proportion of the useful component - the sorption-active mineral montmorillonite. The porosity of the BET method was determined (measurement of specific surface area and porosity). The accuracy and standardization of the method for determining the adsorption activity have been carried out. An exponential dependence of the adsorption activity on the weight of the sample, (1.0 g), sorption time (35 min) and the equilibrium concentration of the dye solution (39 ml 0.15%) were established. The physicochemical and textural properties of betonies clay for the use of catalysis have been studied. It was found that bentonite clay for use in catalysis is a light gray powder, odorless, practically insoluble in water and organic solvents, with a particle size of less than 0.3 mm.

ABSTRACT This research studies the purification of montmorillonite from natural Iraqi bentonite clay (NIBC). Montmorillonite was characterized using XRD, SEM‐EDX, TEM, FTIR, DRS, and UV–vis spectrophotometry. The purified montmorillonite is then employed as an adsorbent and the catalytic degradation of organic aqueous pollutants, specifically Methylene Blue (MB). The results show that the selected organic pollutant MB was removed using both adsorption and catalytic degradation. Different isotherms were applied, including Langmuir, Freundlich, and Temkin. Kinetic and thermodynamics were also studied; MB adsorption followed the pseudo‐second‐order model, and the heat of adsorption for MB was (Δ H ° = −19.1 kJ/mol), indicating a physical process. The catalytic degradation was examined utilizing different redox agents, including H 2 O 2 , NaBH 4 , and KBrO 3 . Box‐Behnken Design (BBD) was applied to study the catalytic degradation; hence, ANOVA analysis shows the significant role of H 2 O 2 concentration ( p = 0.0141), and the synergistic effects were observed for H 2 O 2 ‐NaBH 4 ( p = 0.0082) and NaBH 4 ‐KBrO 3 ( p = 0.0012) interactions. Furthermore, Density Functional Theory (DFT), DFTB+, and molecular dynamic (MD) were applied to get a better understanding of the molecular level. Theoretical calculations, including HOMO–LUMO analysis, electron density difference (EDD), global reactivity descriptors, and Density of States (DOS), were all employed. The montmorillonite exhibits a narrow HOMO–LUMO gap (0.05 eV), high electrophilicity (ω = 18.71), and low hardness (η = 0.0242), indicating excellent electron‐transfer capability. DOS shows the availability of Fe‐d orbitals and Si‐p orbitals near the Fermi level, which facilitate the oxidation and reduction process. These results could provide a mechanistic insight into montmorillonite catalytic performance in catalytic environmental remediation.

The oil and gas industry causes man-made changes in all soil components, as well as in water and plants. Crude oil and gas are processed at the same time as the product is produced, and gas condensate and millions of tons of waste are ignored. Recycling of oil and gas waste products is essential. Sulfur is widely used in agriculture as a fertilizer and part to fight various plant pests. Soon, not only will the issue of using sulfur dioxide waste as raw materials be solved, but also the problem of contamination of environmental bodies with biological pollutants will be avoided. The use of sulfur-based waste from the oil industry is very effective for antibacterial formulations based on ammonium salts and natural bentonite materials. The developed antibacterial drug can be used to disinfect various facilities. The production tests conducted show the necessity of using the proposed disinfectants to improve the environment. This paste, which includes the proposed bactericidal preparation and bentonite clay in its composition, can be used in veterinary medicine to treat necrobacteriosis in animals. Based on our results, Ammonium sulfate and potassium sulfate obtained from sulfur-containing wastes can be used as fertilizers, and their mixture with bentonite clay can be used as an enhancer in agriculture.