Search Results (224)

To address the issue of excessive chemical fertilizer use in agricultural production, this study conducted a pot experiment with four treatments: CK (no fertilization), T1 (the application of potassium magnesium sulfate fertilizer), T2 (the application of slow-release fertilizer equal to T1), and T3 (the application of slow-release fertilizer with the same fertility as T1). The effects of these treatments on garlic seedling yield, growth quality, chlorophyll content, photosynthetic characteristics, and the soil environment were investigated to evaluate the feasibility of replacing conventional fertilizers with slow-release formulations. The results showed that compared with CK, all three fertilized treatments (T1, T2, and T3) significantly increased the plant heights and stem diameters of the garlic sprouts (p < 0.05). Plant height increased by 14.85%, 17.81%, and 27.75%, while stem diameter increased by 9.36%, 8.83%, and 13.96%, respectively. Additionally, the chlorophyll content increased by 4.34%, 7.22%, and 8.05% across T1, T2, and T3, respectively. Among the treatments, T3 exhibited the best overall growth performance. Compared with those in the CK group, the contents of soluble sugars, soluble proteins, free amino acids, vitamin C, and allicin increased by 64.74%, 112.17%, 126.82%, 36.15%, and 45.43%, respectively. Furthermore, soil organic matter, available potassium, magnesium, and phosphorus increased by 109.02%, 886.25%, 91.65%, and 103.14%, respectively. The principal component analysis indicated that soil pH and exchangeable magnesium were representative indicators reflecting the differences in the soil’s chemical properties under different fertilization treatments. Compared with the CK group, the metal contents in the T1 group slightly increased, while those in T2 and T3 generally decreased, suggesting that the application of slow-release fertilizer exerts a certain remediation effect on soils contaminated with heavy metals. This may be attributed to the chemical precipitation and ion exchange capacities of phosphogypsum, as well as the high adsorption and cation exchange capacity of bentonite, which help reduce the leaching of soil metal ions. In summary, slow-release fertilizers not only promote garlic sprout growth but also enhance soil quality by regulating its chemical properties. Full article

This study investigates cement–bentonite slurries with hydration accelerators for borehole backfilling applications in infrastructure reconstruction projects. Two formulations with different accelerator dosages (5 and 10 kg/m³) were evaluated through combined experimental testing and Moving Particle Semi-implicit (MPS) numerical modeling to optimize material performance. The research focuses on time-dependent rheological evolution and its impact on construction performance, particularly bleeding resistance and workability retention. Experimental flow tests revealed that both formulations maintained similar initial flowability (240–245 mm spread diameter), but the higher accelerator dosage resulted in 33% flow reduction after 60 min compared to 12% for the lower dosage. Bleeding tests demonstrated significant improvement in phase stability, with bleeding rates reduced from 2.5% to 1.5% when accelerator content was doubled. The MPS framework successfully reproduced experimental behavior with prediction accuracies within 3%, enabling quantitative analysis of time-dependent rheological parameters through inverse analysis. The study revealed that yield stress evolution governs both flow characteristics and bleeding resistance, with increases several hundred percent over 60 min while plastic viscosity remained relatively constant. Critically, simulations incorporating time-dependent viscosity changes accurately predicted bleeding behavior, while constant-viscosity models overestimated bleeding rates by 60–130%. The higher accelerator formulation (10 kg/m³) provided an optimal balance between initial workability and long-term stability for typical borehole backfilling operations. This integrated experimental–numerical approach provides practical insights for material optimization in infrastructure reconstruction projects, particularly relevant for aging infrastructure requiring proper foundation treatment. The methodology offers construction practitioners a robust framework for material selection and performance prediction in borehole backfilling applications, contributing to improved construction quality and reduced project risks. Full article

Clay is a widely used material with unique properties that vary depending on water content and applied pressure. In this study, the electromechanical behavior of clay samples from Afyonkarahisar, Turkey, is investigated by examining the relationship between electrical resistivity, water content, and mechanical loading under uniaxial pressure. The samples with a water content of 10%, 20%, and 30% were tested using a uniaxial loading machine in accordance with ASTM D 2216 and the Turkish standard TS 1900-1. The analysis included measurements of stress, deformation, and electrical conductivity of the soil. A comparative assessment of samples with varying water content revealed that at low moisture levels (10%), the specific electrical resistivity initially decreases due to soil compaction and reduced porosity. However, as stress increases further, resistivity rises significantly as microcracks begin to develop, disrupting conductive pathways. In contrast, at higher water contents (20% and 30%), resistivity consistently decreases with increasing stress, while conductivity increases markedly. This indicates that at elevated saturation levels, the presence of water facilitates charge carrier mobility through ionic conduction, resulting in lower resistivity and higher conductivity. Comparisons with previous studies on clays such as bentonite and kaolinite reveal similar qualitative trends, although differences in the rate of resistivity change suggest a distinct mineralogical influence in Afyonkarahisar clay. This study contributes to a deeper understanding of the geotechnical behavior of this regional clay and supports more accurate performance predictions in engineering and construction applications. Full article

This study examines the formation of the clay mineral simonkolleite (Skl) in bentonites contaminated with zinc(II) chloride (ZnCl₂), a process that has been little documented in heterogeneous systems such as contaminated bentonites. We explain the contamination mechanisms and provide new insights into the mineralogical, structural, and physicochemical transformations occurring within these materials. The objective, explored for the first time, was to assess how the ZnCl₂-induced mineral phase formation influences the properties of bentonites used as sealing materials, particularly regarding changes in specific surface area and porosity. Three bentonites were analyzed: Ca-bentonite from Texas (STx-1b), Na-bentonite from Wyoming (SWy-3), and Ca-bentonite from Jelsovy Potok, Slovakia (BSvk). Treatment with ZnCl₂ solution led to ion exchange and the formation of up to ~30% simonkolleite, accompanied by a concurrent decrease in montmorillonite content by 9–30%. A suite of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS), was employed to characterize these transformations. The contamination mechanism of ZnCl₂ involves an ion exchange of Zn²⁺ within the montmorillonite structure, the partial degradation of specific montmorillonite phases, and the formation of a secondary phase, simonkolleite. These transformations caused a ~50% decrease in specific surface area and porosity as measured by the Brunauer–Emmett–Teller (BET) nitrogen adsorption and Barrett–Joyner–Halenda (BJH) methods. The findings raise concerns regarding the long-term performance of bentonite-based barriers. Further research should evaluate hydraulic conductivity, mechanical strength, and the design of modified bentonite materials with improved resistance to Zn-induced alterations. Full article

Over the past several decades, extensive research has advanced the understanding of liquefaction in clean sands and sand–silt mixtures under seismic loading. However, the influence of plastic (i.e., clayey) fines on the liquefaction behavior of sandy soils remains less well understood. This study investigates how the quantity and plasticity of fines affect both the susceptibility to liquefaction and the resulting failure mode. A series of stress-controlled cyclic triaxial tests were conducted on sand specimens containing varying proportions of non-plastic silt, kaolinite, and bentonite. Specimens were prepared at a constant relative density with fines content ranging from 0% to 37%. Two liquefaction modes were examined: flow liquefaction, characterized by sudden and large strains under undrained conditions, and cyclic mobility, which involves gradual strain accumulation without complete strength loss. The results revealed a clear relationship between soil plasticity and liquefaction mode. Specimens containing non-plastic fines or fines with a liquid limit (LL) below 20% and a plasticity index (PI) of 0 exhibited flow liquefaction. In contrast, specimens with LL > 20% and PI ≥ 7% consistently displayed cyclic mobility behavior. These findings help reconcile the apparent contradiction between laboratory studies, which often show increased liquefaction susceptibility with plastic fines, and field observations, where clayey soils frequently appear non-liquefiable. The study emphasizes the critical role of plasticity in determining liquefaction type, providing essential insight for seismic risk assessments and design practices involving fine-containing sandy soils. Full article

Sustainable agriculture increasingly relies on strategies that improve soil fertility while reducing the environmental footprint of chemical inputs. The primary objective of this research was to disentangle the individual and combined effects of crop rotation and fertilization on soil quality. This study aimed to determine whether the effectiveness of fertilization was modified by rotational practices—exploring whether these interactions were additive, antagonistic, or synergistic. This study assessed the impact of two-year open-field crop rotations—broccoli–tomato and broccoli–pepper—combined with organic and mineral fertilization on soil chemical and biological properties. Treatments included sulfur bentonite enriched with orange waste (SBO), horse manure (HM), mineral fertilizer (NPK), and an unfertilized control (CTR). Soil samples were collected after each crop cycle and analyzed for enzymatic activities (fluorescein diacetate hydrolase, dehydrogenase, catalase), microbial biomass carbon (MBC), organic matter, total nitrogen, and macro- and micronutrient content. The results showed that organic amendments, particularly SBO and HM, significantly increased microbial activity, MBC, and nutrient availability compared to NPK and CTR. Organic treatments also led to a reduction in soil pH (−12%) and a more balanced ionic profile, enhancing soil biological fertility across both rotations. By contrast, the NPK treatments favored higher nitrate and chloride concentrations (3.5 and 4.6 mg * g⁻¹ dw, respectively) but did not improve biological indicators. Improvements were more pronounced in the second crop cycle, suggesting the cumulative benefits of organic amendments over time. These findings highlight the potential of combining organic fertilization with crop rotation to enhance soil health and support long-term sustainability in horticultural systems. Full article

In this study, a statistical analysis of results reported in the literature was conducted through a 2ⁿ experimental design on the synthesis of bifunctional catalysts used in the production of lighter fuels, aiming for optimization while considering factors such as support (bentonite and vermiculite), acidity modifier (zirconium and cerium), metal (tungsten and molybdenum), metal content (5% and 10%), promoter (nickel and cobalt), and heteropolyacids (tungstophosphoric acid and molybdophosphoric acid), identifying their influence on textural properties and catalytic performance. Regarding the textural properties, vermiculite proved to be the most favorable support due to its high porosity. It was also established that the implemented metals impart positive characteristics to the catalysts due to their various properties; however, incorporating large amounts led to an adverse effect by clogging the pores. Catalytic performance was analyzed in isomerization and cracking reactions, which were enhanced by the use of cerium due to the presence of Brønsted acid sites and molybdenum for its stability. In this way, the statistical analysis conducted in this study was crucial for identifying the influence of key factors on the textural properties and catalytic performance of bifunctional catalysts. Using a 2ⁿ experimental design allowed for a systematic evaluation of variables reported in the literature, such as support, acidity modifiers, metals, metal content, promoters, and heteropolyacids. Full article

A barrier wall is a vertical engineered layer designed to block contaminated soil, thereby controlling pollution sources, preventing pollutant migration to groundwater, and limiting pollution spread. Cement–bentonite barrier walls, widely adopted for their seepage control capability, structural strength, and cost-effectiveness, face sustainability challenges due to high cement consumption. This study systematically investigates the coupled effects of steel slag substitution rate and bentonite dosage on the mechanical–permeability of barrier materials for the first time and proposes steel slag (containing dicalcium silicate (C₂S) and tricalcium silicate (C₃S) phases similar to cement clinker) as a partial cement substitute in steel slag–cement–bentonite barrier materials, aiming to reduce cement usage and utilize industrial waste. Through unconfined compressive strength tests, direct shear tests, and variable head permeability tests, the effects of steel slag substitution rates (0~50%) and bentonite dosages (46~54%) on material performance were systematically investigated. Key findings include (1) unconfined compressive strength decreases linearly with increasing steel slag substitution but grows exponentially with bentonite dosage; (2) cohesion exhibits a negative exponential relationship with steel slag substitution and a linear positive correlation with bentonite content—the unconfined compressive strength of the materials with bentonite dosage of 50% and 54% were 1.51 and 2.84 times higher than those with bentonite dosage of 46%, respectively; (3) cohesion and unconfined compressive strength conform to c = (0.23~0.39)q_u; (4) permeability decreases with higher steel slag substitution and bentonite dosage, achieving controlled low permeability (<1 × 10⁻⁷ cm/s). This research provides a sustainable solution for barrier wall construction by integrating waste recycling and performance optimization. Full article

The increasing use of nanostructured silver-containing inorganic materials raises concerns about their impact on aquatic organisms. This study assessed the toxicity of silver-modified bentonite composites on Chlamydomonas sp. Two materials were tested: silver-exchanged bentonite (Ben-Ag) and its reduced form (Ben-Ag (H₂)).Microalgae were exposed to 0.5 IC₅₀, 1.5 IC₅₀, and 2 IC₅₀. Ben-Ag showed higher toxicity than Ben-Ag (H₂), which even promoted algal growth at low doses. Fluorescence microscopy revealed morphological shrinkage in treated cells. Increased phenol content, elevated malondialdehyde (MDA) levels, and altered antioxidant enzyme activities further confirmed Ben-Ag toxicity, along with reduced growth and photosynthetic pigments. Transcriptomic analysis revealed significant changes in gene expression under Ben-Ag exposure. Genes involved in photosynthesis (petB, psbL), caspase activity (casp), and carotenoid metabolism (Q2CHY) were down-regulated, indicating stress-induced damage. In contrast, genes encoding stress response enzymes (SOD, peroxidase), carbon metabolism enzymes (rbcL, PGQ1), and β-carotene biosynthesis (Q2BKT) were up-regulated, reflecting cellular defense mechanisms. Overall, the study highlights the high toxicity of Ben-Ag to Chlamydomonas sp., emphasizing the importance of evaluating environmental risks before using such materials in aquatic environments. Full article

With the advancement of aero-engine thrust-to-weight ratios, turbine blades now incorporate complex hollow structures fabricated using ceramic cores. The emergence of light-curing 3D printing technology for ceramic cores offers a viable solution to producing such complex structural components. To avoid the breakage of the core when removing the support after the printing of the general paste, we used a rheological additive, organic bentonite, to prepare a light-curing 3D-printed silicon-based ceramic core paste that can allow for unsupported printing. This study pursues two primary research objectives: Firstly, the effect of organic bentonite on the rheological behavior and stability properties of silicon-based ceramic was investigated. Secondly, we conducted a comprehensive analysis of how organic bentonite modification influences the performance of silicon-based ceramics. The results show that, firstly, the addition of organic bentonite dramatically improves the rheology and stability of silicon-based ceramic paste, and that the optimal content is between 1 and 2 wt.% for the best effect. Second, after the primary sintering process (1250 °C), partial bentonite can produce a small amount of cordierite phase and promote the generation of cristobalite. The room-temperature performance of the ceramic core can be improved. However, organic bentonite, after secondary sintering at 1550 °C, completely forms cordierite and reduces the amount of square quartz produced. Then, it negatively affects the high-temperature performance of the ceramic core. Therefore, when the content of organic bentonite is 1 wt.%, the ceramic paste has superior rheology and stability, making unsupported printing possible. Our study revealed an apparent porosity of 32.43%, a bulk density of 1.64 g/cm³, a sintering shrinkage value of 2.94%, a room-temperature flexural strength of 24.7 MPa, a high-temperature (1550 °C) flexural strength of 10.1 MPa and a high-temperature deflection of 1.24 mm, which meet the requirements of core printing. Full article

Cement–bentonite cut-off walls are widely used in geoenvironmental engineering such as landfill liners and contaminated site remediation, due to their low permeability and structural stability. However, excessive cement use reduces the swelling capacity of bentonite and increases environmental burdens. This study proposes incorporating polypropylene fibers (PPFs) into cement–bentonite cut-off walls to improve their performance under lower cement dosages. A total of 16 formulations were tested with different cement and fiber contents. Unconfined compressive strength (UCS), direct shear, and falling head permeability tests were conducted over 7, 14, and 28 days, respectively. Microstructural changes were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that compared to the conventional high-cement mixture without fibers, a formulation with moderate cement content and 2% PPF achieved higher compressive strength, comparable shear strength, and significantly lower permeability. Microstructural analysis confirmed that fiber addition enhanced cement hydration and preserved bentonite, forming a compact microstructure with reduced porosity. Furthermore, cost and carbon emission analyses revealed that the above optimized formulation reduced both material cost and embodied carbon by approximately 12.5% and 22.3%. These findings provide a sustainable and cost-effective approach to improve the mechanical and hydraulic performance of cement–bentonite cut-off walls. Full article

Heavy metal (HMs) toxicity has severely impacted wheat production and is considered an emerging threat to human health due to bioaccumulation. The application of organic and inorganic amendments has proven effective in mitigating HM’s phytotoxicity by limiting their mobility in soil and plants. A pot experiment was conducted to evaluate the efficiency of biochar (BC), bentonite (BN), and rock phosphate (RP), both individually and in combination, in alleviating lead (Pb) toxicity and enhancing wheat growth, and physiological attributes. The present investigation revealed that BC, BN, RP, and their combined mineral biochar amendments (MBAs) at 1.5% level significantly enhanced wheat growth along with reducing DTPA-extractable Pb in soil by 30.0–49.8% and Pb uptake in roots by 15.7–37.5% and in shoots by 34.5–48.5%. Antioxidant enzymatic activities were improved, and stress indicators were reduced in roots and shoots of wheat under Pb stress, including hydrogen peroxide (H₂O₂) by 50.7 and 81.0%, malondialdehyde (MDA) levels by 16.0 and 74.9%, and proline content by 34.5 and 64.0%, respectively. The effectiveness of the treatments is described in descending order viz. MBA-1 > MBA-3 > MBA-2 > BC > RP > BN under Pb stress. In conclusion, the integration of biochar, bentonite, and rock phosphate is a promising strategy for sustainable and cleaner cereal crop production under heavy metal stress conditions. Full article

Gas extraction from coal seams can significantly mitigate gas accidents and improve resource utilization. The effectiveness of borehole sealing directly determines the concentration and efficiency of gas drainage. In recent years, liquid-phase sealing materials, represented by non-solidifying pastes, gel-based materials, and inorganic retarders, have gradually become a research hotspot. Compared to the traditional solid sealing materials such as cement-based or organic polymers, liquid-phase sealing materials can effectively seal secondary fractures caused by mining vibration through grout replenishment. However, the influence of each component in liquid-phase non-solidified materials on sealing properties such as fluidity, water retention, and permeability remains unclear. To address these issues, a novel liquid-phase non-solidified hole sealing material was developed using bentonite as the base material, sodium dodecyl benzene sulfonate as the dispersant, and sodium carboxymethyl cellulose as the thickener. Initially, single-factor experiments were applied to investigate the effects of material ratios on the fluidity, water retention, and permeability. Subsequently, orthogonal experimental design and response surface methodology were used to establish nonlinear quadratic regression models relating these properties to water–bentonite ratio, dispersant content, and thickener content. The results indicated that an optimal water–bentonite ratio enhances both fluidity and permeability, while dispersants improve water retention and permeability and thickeners primarily boost water retention. Finally, the optimized composition was determined as a water–bentonite ratio of 4.41:1, a dispersant content of 0.38%, and a thickener content of 0.108%. We believe that the developed slurry materials will maintain excellent sealing performance through the entire gas extraction period. Full article

The application of slow-release fertilizers is essential for improving fertilizer utilization efficiency and promoting sustainable agricultural development. Unlike traditional single organic polymer-coated or inorganic-coated fertilizers, this study utilized biodegradable modified polyvinyl alcohol (PVA) as a binder and cheap, readily available phosphogypsum–bentonite as an inorganic coating material to develop a novel slow-release potassium magnesium sulfate fertilizer (SRPMSF). This study initially examined the influence of SA dosage on PVA properties. XRD, FTIR, TGA, and water resistance analyses revealed that sodium alginate exhibits good compatibility with polyvinyl alcohol, enhancing its heat and water resistance. Ultimately, PVA–SA-2 (1.2% sodium alginate) was chosen as the optimal binder for SRPMSF production. Furthermore, this study investigated the impact of bentonite on the physical and slow-release properties of the SRPMSF by varying the phosphogypsum-to-bentonite ratio. This experiment included five treatment methods: the treatments consist of SRPMSF-1 (0 g bentonite), SRPMSF-2 (phosphogypsum/bentonite ratio of 4:1), SRPMSF-3 (3:2), SRPMSF-4 (2:3), and SRPMSF-5 (1:4). A control group (PMSF) was also included. The results indicated that, as the bentonite content increased, both the particle size and compressive strength of the coated slow-release fertilizer increased, with the SRPMSF particle sizes ranging from 3.00 to 4.50 mm. The compressive strength of the SRPMSF ranged from 20.85 to 43.78 N, meeting the requirements for industrial production. The soil column leaching method was employed to assess the nutrient release rate of the fertilizers. The experimental results indicated that, compared to the PMSF, the SRPMSF effectively regulated nutrient release. Pot experiments demonstrated that the SRPMSF significantly enhanced garlic seedling growth compared to the PMSF. In conclusion, a new type of slow-release fertilizer with good slow-release performance is prepared in this paper, which can improve the utilization rate of fertilizer and reduce the economic loss and is conducive to the sustainable development of agriculture. Full article

Portulaca oleracea L. is an important herb with the same origin in medicine and food. To achieve the precise sowing of P. oleracea, this study employed a mixed experimental design to optimize the pellet formulation of the seeds. Fillers such as kaolin, bentonite, and talcum powder were used, along with binders including polyvinyl alcohol, sodium alginate, and sodium carboxymethyl cellulose. The physical characteristics and germination properties of the pelletized seeds were evaluated to determine the optimal formulation. The results indicated that, after pelletizing, the seeds exhibited a higher seed viability and vigor, germination rate, and germination index. Specifically, the seed singulation rate correlated positively with the kaolin content, the disintegration rate was proportional to the amount of talcum powder added, and the compression resistance was positively correlated with the bentonite ratio. Using response optimization, the optimal formulation of fillers used for pelletizing P. oleracea seeds was identified as 17% talcum powder, 16% kaolin, and 67% bentonite. Single-factor experiments showed that using PVP as a binder at a mass fraction of 10% resulted in improved pelletizing indices. This study not only optimized the pelletizing formulation of P. oleracea seeds based on physical and germination properties, but also expanded the application of pelletizing in the processing of the seeds of traditional Chinese herbs. It holds significant implications for the mechanized production of small, pelletized seeds of traditional Chinese herbs. Full article