Search Results (27,625)

The aqueous phase (AP) produced during hydrothermal liquefaction (HTL) contains high organic loads and a chemically complex mixture of dissolved intermediates, posing significant environmental management challenges. Aqueous phase recycling (APR) has emerged as a strategy to enhance bio-crude yield, improve energy recovery, and reduce freshwater consumption by reintroducing reactive water-soluble species into subsequent cycles. However, repeated recycling can lead to the accumulation of N-containing compounds and phenolics, potentially diminishing bio-crude quality and heating value through secondary polymerization and condensation reactions. Simultaneously, the carbon and nutrient-rich character of AP presents opportunities for valorization via anaerobic digestion, microalgae cultivation, and supercritical water gasification. Despite growing interest, APR-HTL research remains feedstock-specific, and a systematic understanding of AP compositional evolution across multiple recycling cycles is limited. This review synthesizes recent progress, highlighting mechanistic linkages between AP composition, bio-crude performance, and integrated biorefinery strategies. Full article

The aim of this study was to investigate the effects of exogenous gibberellin (GA₃) and uniconazole (S₃₃₀₇) on the growth of C. oleifera spring shoots, and ultimately to seek ways to improve the quality of its panicles. Five-year-old ‘Huaxin’ trees were sprayed with 2400 mg/L GA₃ or 800 mg/L S₃₃₀₇ at the leaf expansion stage. Growth parameters, physiological indicators, and endogenous hormone levels were measured. The results showed that GA₃ significantly enhanced shoot extension and internode lengthening, whereas S₃₃₀₇ treatment exhibited the opposite inhibitory effects. GA₃ treatments increased the content of soluble sugar, enhanced the activity of SOD and POD, decreased the activity of CAT, decreased MDA accumulation, indicating that membrane lipid peroxidation was alleviated. The results of endogenous hormone analysis indicated that GA₃ and S₃₃₀₇ reduced the concentration of ABA and IAA, increased the content of tZ, and altered the distribution of endogenous GA₃. Overall, GA₃ enhanced spring shoot growth by regulating endogenous hormone balance, enhancing nutrient accumulation and antioxidant capacity. These results provide the theoretical and technical basis for the high-quality spike formation and high-yield of cultivation of C. oleifera. Full article

To address freshwater scarcity in agriculture, the use of brackish and reclaimed water for alternate irrigation has emerged as a viable alternative. This study evaluated four biochars (rice husk, peanut shell, rice straw, and wheat straw, applied at 2%) and three silicon fertilizers (Lang-Si (S1), Nayou-Si (S2), and sodium metasilicate pentahydrate (S3)) as amendments for sandy loam soil (Lang-Si, Nayou-Si, foliar spray at 1000× dilution; sodium metasilicate pentahydrate, foliar spray at 150 mg∙L⁻¹). Their effects on soil salinity, physicochemical properties, and microbial community structure were assessed under alternate irrigation with brackish and reclaimed water. Alternate irrigation reduced soil electrical conductivity and increased total phosphorus (TP) content compared to single-source irrigation. The effects of amendments varied by type. Biochars improved soil fertility and reduced salinity: peanut shell biochar decreased EC by 15.5%; rice husk biochar increased total nitrogen (TN), TP, and organic matter (OM) by 11.8%, 8.2%, and 10.1%, respectively; and wheat straw biochar elevated subsurface soil TN and OM by 14.1% and 40.0%. Straw-derived biochars and sodium metasilicate pentahydrate maintained higher bacterial α-diversity (Shannon index ≥ 6.67). These effects corresponded with the nutrient adsorption capacity of biochars and the ionic stress alleviation by soluble silicon. The correlation analysis identified OM, TN, TP, and EC as the key drivers shifting the microbial community. Straw-derived biochars and sodium metasilicate pentahydrate are suitable amendments for alternate irrigation systems. These materials balance salinity control, fertility improvement, and microbial conservation, offering practical options for sustainable use of brackish and reclaimed water in agriculture. Full article

Trace metal contamination in lotic freshwater systems exhibits pronounced heterogeneity arising from coupled hydrological connectivity, geochemical partitioning, and anthropogenic forcing, complicating exposure characterization in urban and peri-urban catchments. Addressing this complexity requires integrative analytical approaches capable of deciphering system-level controls, prompting an investigation of the environmental structuring and governing controls of dissolved trace metal signatures in a human-impacted stream using a system-oriented computational framework. To capture temporal variability associated with seasonal hydrological contrasts and heterogeneous pollution inputs, a station-based, season-resolved sampling strategy was implemented during the wet and dry seasons. Physicochemical gradients (pH, temperature, dissolved oxygen, and electrical conductivity), inorganic nitrogen species (NH₃, NO₂⁻, and NO₃⁻), and phosphorus fractions (total phosphorus, TP; total orthophosphate, TOP; soluble reactive P, SRP) were jointly analyzed with dissolved concentrations of chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). Regression-based machine learning models were used to quantify element-specific sensitivities to hydrochemical drivers under wet–dry periods and to identify optimal predictive configurations. Predictive performance was consistently high for trace metals (R² generally >0.95), with Random Forest providing the best accuracy for Cr, Ni, Pb, Cd, As, and Hg, whereas Cu was most reliably captured by an XGBoost tree ensemble (R² = 0.994). Explainability analyses revealed heterogeneous, metal-specific control regimes: Cr was primarily driven by temperature, Ni by NO₂⁻ and redox-sensitive conditions, Cd by NH₃ and temperature, and As by Hg in combination with phosphorus-related and redox-linked proxies, while Pb showed comparatively lower predictability relative to other metals. Trace metal distributions are therefore structured primarily by differential environmental sensitivity rather than uniform source-driven inputs, reinforcing the need for integrative computational frameworks when interpreting freshwater contamination under intensifying anthropogenic and climatic pressures. Full article

Effective electrochemical CO₂ reduction to liquid fuels requires that the local catalytic environment facilitates the desired reactivity, yet a microscopic understanding of this environment is difficult to achieve from experiment alone. In this work, a 3D reaction-diffusion model was developed to explore the effects of electrode surface area and local geometry on the performance of a heterogeneous catalyst that performs a two-step CO₂ reduction cascade reaction to CO and then CH₃OH under aqueous conditions. Kinetic parameters for the model were inspired by experimental results using a cobalt phthalocyanine (CoPc) catalyst. Three-dimensional architectures composed of arrays of square pillars with varying dimensions and either smooth or periodically modulated surfaces were tested, revealing the extent to which geometry modulates the performance of the cascade reactions. Although structural variations modulate local concentration gradients, we find that electrochemically active surface area predominantly governs the overall cascade reaction. Moreover, the results suggest that supersaturation of CO, with concentrations up to ten-fold higher than the equilibrium solubility limit, might be critical for more efficient conversion to CH₃OH. For any given geometry, the spatially averaged ratio of [CO] to [CO₂] is dictated by the electrochemically active surface area and determines the yield of CH₃OH. For a fixed surface area, geometries that spatially confine the electrolyte yield moderate local [CO] to [CO₂] ratios within small volumes. In contrast, less confining geometries result in a broader distribution of local ratios spread over larger volumes, with both configurations yielding the same spatially averaged [CO] to [CO₂] ratio. These insights provide valuable design principles—highlighting the critical importance of surface area and possibly CO supersaturation—for engineering advanced electrode architectures that leverage intermediate trapping and CO supersaturation to enhance overall performance in tandem CO₂ reduction systems. Full article

The solubilization of poorly water-soluble drugs remains a critical challenge in pharmaceutical research. The formulation of solid dispersions employing mesoporous silica nanoparticles (MSN) constitutes a key strategy for enhancing the hydrophilicity and oral bioavailability of Biopharmaceutics Classification System (BCS) Class II drugs. Although several commercial mesoporous silica excipients have been approved for pharmaceutical use, there remains room for improvement regarding drug loading capacity, stability, and controllability of drug release. Methods: for this purpose, dendritic mesoporous silica nanoparticles (DMSN) with a radial dendritic structure and pH-responsive degradation properties were designed and synthesized using celecoxib (CEL) as the model drug, featuring a pore size of 21.51 nm. CEL was loaded onto DMSN and seven commercial solid dispersion excipients using the solvent evaporation method. Results: owing to its high surface area, pore volume, and radial structure, DMSN achieved 39.72% drug loading in an amorphous state, markedly improving wettability, dissolution, and physical stability. Accelerated stability tests showed that DMSN inhibited recrystallization, outperforming traditional solid dispersions. Pharmacokinetic studies in rats demonstrated that the oral bioavailability of CEL-DMSN was 1.29-fold higher than that of commercial celecoxib capsules. Conclusions: in conclusion, these results confirmed the potential of DMSN in enhancing the stability, promoting oral absorption, and reducing gastrointestinal irritation of poorly soluble drugs. Full article

The spatial variability of soil physicochemical properties significantly influences irrigation efficiency, nutrient availability, and the long-term sustainability of irrigated agriculture in semi-arid regions. This study aimed to quantify and model the spatial distribution of soil properties in a semi-arid irrigation district in central Mexico (Irrigation District 001 “Pabellón de Arteaga”, Aguascalientes), providing spatially explicit information for differential irrigation and fertilization management. Ninety-seven crop and four natural sampling sites were established under a stratified random design at two soil depths (0–30 and 30–60 cm). Geostatistical and machine learning models (Ordinary Kriging, OK; Generalized Additive Models, GAM; and Random Forest, RF) were applied to predict spatial patterns, and their performance was evaluated using statistical metrics. The findings reveal high spatial and vertical variability, with most properties (such as organic matter, total nitrogen, and texture) showing significant stratification with depth. In contrast, others (pH and electrical conductivity, EC) remained remarkably homogeneous vertically. Correlation patterns were identified, highlighting the negative influence of alkaline pH (≈8.0) on the availability of micronutrients (Fe²⁺ and Mn²⁺) and the positive association between EC and soluble cations (Ca²⁺, K⁺, and Na⁺). Moran’s Index confirmed significant spatial autocorrelation for most properties, reducing the effective sample size by 30–70%. The comparative evaluation of predictive models demonstrated the superiority of RF over OK and GAMs for predicting chemical properties, thanks to its ability to capture nonlinear relationships and complex interactions. However, the overall predictive performance was moderate, reflecting the multifactorial complexity of the edaphic system. This study lays the foundation for the development of an accessible, low-cost Decision Support System by providing a robust methodological framework for spatial soil characterization and contributing to more sustainable, resilient agriculture, where decision-making is based on quantitative data and predictive models. Full article

The origin of Mesozoic granites associated with the Dahutang W-Cu-Mo orefield in northern Jiangxi, which hosts the world’s second-largest tungsten deposit, remains a compelling subject despite extensive geochemical and geochronological studies. In this contribution, we present wolframite mineral and whole-rock geochemistry, as well as monazite and zircon U-Pb ages, for the Mesozoic granites to constrain our understanding of the petrogenesis of these granites and their coupling relationship with the mineralization. The following two magmatic phases and four types of rocks in the study area are identified: the early stage (152–147 Ma) biotite (G1) granites and the late stage (144–130 Ma) two-mica (G2),muscovite (G3), and albite (G4) granite series. These two magmatic phases are temporally coincident with two mineralization stages (~150 Ma and 144–139 Ma). All the Mesozoic granites share the characteristics of high silica content, peraluminosity (A/CNK > 1.1), and low Zr + Nb + Ce + Y values (<200 ppm); they are derived from the partial melting of a Proterozoic crustal source and classified as S-type granites. Specifically, the G1 granites are characterized by relatively high MgO (~0.5%), CaO (~1%), and low P₂O₅ (0.13%–0.20%). They formed through a relatively high degree of partial melting at approximately 766 °C (zircon saturation temperatures), a process influenced by biotite dehydration reactions, with minor contributions from mantle-derived materials. In contrast, the G2–G4 granite series exhibits more typical peraluminous S-type granite features, such as high Al₂O₃, Na₂O, and P₂O₅ (mostly > 0.2%) contents, and low Sr and Ba contents. They are products of low-degree partial melting that occurred under conditions close to muscovite breakdown at ~726 °C. Additionally, fluid–melt interaction is recorded in both granites by distinctive geochemical signatures, including enrichment in Sn (>30 ppm), Cs (>35 ppm), Li (>250 ppm), F (>0.4%), and W (10–1000 ppm), coupled with low K/Rb (<150) and Nb/Ta (<5) ratios. The near-chondritic Zr/Hf (22.6–34.1) and Y/Ho (24.5–31.5) ratios of the G1 granites imply a relatively limited role of magmatic fluid–melt interaction during its evolution. For the G2–G4 granites, however, intense crystal fractionation and late-stage fluid–melt interaction are well-documented by their highly variable and low ratios of Y/Ho (14.8–41.4), Nb/Ta (0.89–5.57), Zr/Hf (8.84–41.67), and K/Rb (13.96–128.29). In the long-lived, reduced, and volatile-rich aqueous environment of the G2–G4 magmas, fractional crystallization and albitization collectively enhanced the solubility and hydrothermal transport capacity of W, Sn, Li, Nb, and Ta by multiple orders of magnitude. In contrast, in the earlier, more oxidized G1 magmas (which incorporated mantle materials), the exsolution and hydrothermal transport of Cu and Mo were associated with localized greisenization, but their capacity diminished with fractional crystallization. Historically, mineral exploration in the Dahutang mining area has focused primarily on W, Cu, and Mo. Based on this research, we conclude that there is significant mineral potential for rare metals (particularly Sn, Li, and Ta), and future exploration should prioritize areas adjacent to the evolved G2–G4 peraluminous leucogranites to search for new concealed mineral occurrences. Full article

Elucidating the response mechanisms of seashore paspalum (Paspalum vaginatum) roots to salt stress is crucial for breeding salt-tolerant varieties. This study aimed to investigate the morphological, physiological, and surface electrochemical responses of seashore paspalum roots to salt stress. The salt-tolerant genotype Sealsle2000 and salt-sensitive genotype 17U-45 were subjected to 300 mM salt stress for 4 and 8 days. Results showed that salt stress exerted a more pronounced inhibitory effect on root growth than on shoot growth, with Sealsle2000 exhibiting less growth inhibition compared to 17U-45. Under salt stress, Sealsle2000 adsorbed more Na⁺ on the root surface and sequestered them within the roots than 17U-45; furthermore, Sealsle2000 was able to maintain higher K⁺/Na⁺ ratios. In terms of physiological mechanisms, Sealsle2000 maintained higher activities of superoxide dismutase and catalase, as well as elevated levels of osmotic adjustment substances (proline and soluble sugars) in roots, which collectively alleviated membrane lipid peroxidation damage and osmotic stress. Compared to 17U-45, Sealsle2000 possessed more negative charges and functional groups on the root surface, which contributed to its higher Na⁺ adsorption capacity and enhanced salt tolerance. Collectively, these findings establish a theoretical framework for understanding the salt tolerance mechanisms of seashore paspalum and other plants. Full article

The persistence of water-soluble polymers such as polyvinylpyrrolidone (PVP) in aquatic environments presents a major challenge for conventional wastewater treatment. Herein, a sunlight-active TiO₂/activated carbon (TiO₂/AC) composite fabricated via a simple physical mixing route is reported for the synergistic adsorption and photocatalytic mineralization of PVP K30. The optimal composite (2:1 weight ratio) exhibits a high surface area (412 m² g⁻¹) and an integrated anatase–carbon architecture. The process operates through a sequential “adsorb-and-shuttle” mechanism, whereby PVP is first concentrated on the composite in the dark (30.2% removal in 8 h) and subsequently degraded under solar irradiation. This dual function leads to 86.4% PVP removal and 72.1% total organic carbon (TOC) mineralization, demonstrating true polymer destruction rather than mere surface accumulation. The composite demonstrates robust performance in simulated wastewater, retaining over 68% PVP removal and 55% TOC mineralization in a complex matrix containing competing inorganic ions and natural organic matter. Spectroscopic and thermogravimetric analyses confirm PVP chain scission and near-complete removal of adsorbed residues. An optimized ethanol-washing protocol enables effective catalyst regeneration, with the composite retaining 85% of its initial activity after five cycles. A detailed techno-economic analysis confirms the economic viability of this regeneration strategy at industrial scales (>1000 kg/year), projecting cost savings exceeding 60% compared to fresh catalyst use. Importantly, the PVP-loaded spent TiO₂–AC was successfully repurposed as an electrocatalyst for the urea oxidation reaction, achieving a high current density of 163.7 mA cm⁻², which surpasses the performance of the pristine composite. The greenness of the overall process was validated using analytical eco-scale (ESA), method volume intensity (AMVI), and white analytical chemistry (WAC) metrics. Overall, this work presents a sustainable, solar-driven platform that advances a circular economy model, integrating effective polymer wastewater remediation with subsequent energy valorization of the spent material. Full article

In recent years, sustainability and the concept of a circular economy have grown in importance within almost all industrial sectors. Especially in the chemical industry, recycling of polymer waste streams has become an important pathway to avoid plastic waste being landfilled or incinerated. Additionally, traditional carbon sources, such as fossil fuels, can be substituted with streams of recycled polymer. For example, polyethylene terephthalate (PET), which is utilized in plastic bottles and textiles, may be recycled via glycolysis. This depolymerization yields the monomer bis(2-hydroxyethyl) terephthalate (BHET). This study focuses on the thermal behavior and stability of BHET, both in pure form as well as in the presence of ethylene glycol (EG), as it results from PET glycolysis. For this, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), powder X-ray diffraction (PXRD), and thermogravimetry (TG) were utilized. The results exhibited pure BHET polymerizing to PET at temperatures above 120 °C, while further increasing temperatures increased the reaction kinetics. Additionally, no reaction was observed in BHET/EG mixtures at any temperature investigated, which can be attributed to the presence of EG shifting the equilibrium of the reaction towards the BHET, thus inhibiting polymerization. Based on these results and the determined BHET/EG (solubility) phase diagram, potential purification strategies based on crystallization are proposed. Full article

Background/Objectives: Clonazepam (CLZ), a BCS Class II drug, presents significant oral delivery challenges due to its low aqueous solubility. This study explores the systematic development of solid self-emulsifying drug delivery systems (S-SEDDS) using Quality by Design (QbD). The primary objective was to evaluate and compare advanced mathematical optimization frameworks, specifically Derringer’s Desirability Function (D) and Weighted Goal Programming (WGP), to identify a robust formulation that enhances drug solubilization while ensuring superior processability and flowability. Methods: Liquid SEDDS were solidified by adsorption onto a porous matrix (Aerosil^® 200/Lactose). A multi-objective optimization was conducted to define a robust Design Space (DS), comparing D against WGP. The trade-offs between competing Critical Quality Attributes (CQAs), specifically powder flowability (angle of repose, AR), blending efficiency (BE), and CLZ recovery (CR), were evaluated. Characterization included morphology from Environmental Scanning Electron Microscopy (ESEM), droplet size analysis, and pH-dependent dissolution studies. Results: D provided a highly robust baseline, yielding constant optimal coordinates (F2, F3 = +1; F4 = 0) across all sensitivity levels, with a predicted AR of 40.46°, BE of 0.12 and CR of 90.0%. However, WGP successfully refined this solution by allowing a more flexible weighting of goals, achieving a more favorable compromise with an AR of 38.96°, a BE of 0.11, and a CR of 90.23%. The optimized system maintained nanometric droplet sizes (<200 nm) and showed a controlled, pH-independent release profile, reaching 80% drug solubilization at 6 h. Conclusions: Integrating WGP into the QbD framework offers a more versatile and precise optimization than the traditional D for complex pharmaceutical systems. This approach ensures the production of high-quality S-SEDDS, bridging the gap between mathematical modeling and the stringent requirements of industrial solid dosage manufacturing. Full article

Forests’ conversion to tea plantations is a land use transition type with high economic value in China. How this conversion affects soil weathering and nutrient characteristics remains unclear. Here, we selected six soil profiles (three pairs) from representative tea plantations and adjacent forests in China. We quantified the weathering intensity (chemical index of alteration (CIA), base-to-alumina ratio (ba), and weathering index of Parker (WIP)) by soil geography and elemental geochemistry methods and revealed nutrient distributions along with soil profiles. The results showed that soluble elements (such as K₂O, CaO, MgO and Na₂O) and SiO₂ were noticeably leached, while Al₂O₃ and P₂O₅ were enriched. The geochemical indices showed that the soil profiles of tea plantations (CIA: 80.6%, ba: 0.3 and WIP: 34.6%) experienced stronger chemical weathering than those of forest soils (CIA: 76.0%, ba: 0.4 and WIP: 39.7%). The mean sensitivity indexes (SI) of soil pH, soil organic matter (SOM), total phosphorus (TP) and total potassium (TK) were −7.0%, −24.8%, 53.7% and −8.6%, respectively. This reflected that tea plantations would lead to soil acidification, organic matter depletion, phosphorus enrichment, and potassium deficiency. Our work underscores the significant impact of anthropogenic tea-garden cultivation on pedogenesis; future management must emphasize rational fertilization to prevent soil degradation. Full article

To investigate the effects of different seedless treatments on grape coloring and fruit quality, Vitis vinifera × Vitis labrusca cv. ‘Jumeigui’ were treated with different concentrations of forchlorfenuron (CPPU) (0.5, 1 and 1.5 mg/L), thidiazuron (TDZ) (0.5, 1 and 1.5 mg/L), and 6-benzyladenine (6-BA) (10, 20 and 30 mg/L) in combination with 18 mg/L gibberellic acid (GA₃) during the seedless-fruit-setting period. After the grapes ripened, multiple quality indicators were measured to analyze and evaluate the effects of different treatments on the fruit coloration and quality of ‘Jumeigui’ grapes. The results showed that increasing concentrations of CPPU and TDZ gradually reduced the comprehensive fruit quality of ‘Jumeigui’ grapes. The treatments with 18 mg/L GA₃ + 0.5 mg/L CPPU/TDZ were relatively effective in improving the comprehensive quality of ‘Jumeigui’ grapes. With increasing concentrations of 6-BA, the comprehensive effect initially increased and then decreased. The treatment with 18 mg/L GA₃ + 20 mg/L 6-BA resulted in a soluble solids content of 20.03% and a coloring index of 4.10, demonstrating the best overall improvement in the comprehensive quality of ‘Jumeigui’ grapes. Based on practical production considerations, it is recommended to apply 18 mg/L GA₃ + 20 mg/L 6-BA during the seedless-fruit-setting period of ‘Jumeigui’ grapes to enhance coloring effects and improve fruit quality. Full article

With the development of science and technology, heat dissipation has become a bottleneck problem restricting the development of fields such as transportation, machinery, electronics, and aerospace. Aiming to resolve the bottleneck problem of low thermal conductivity in traditional commercial magnesium alloys, this paper designed alloy compositions to investigate the effects of the solid solubility of La and Ce, and the size, morphology, distribution, and volume fraction of the second phase in the microstructure of magnesium alloys during the heat dissipation performance of the Mg-RE binary system and the Mg-Mn-La(Ce) system. The research shows that through CAFE simulation calculations, regulation can be achieved via the following methods: increasing the average nucleation undercooling, which leads to larger grain sizes; reducing the nucleation density, which results in larger grain sizes; and increasing the standard deviation of the average nucleation undercooling, which reduces the area of small grains while increasing the area of large grains. The thermal conductivity of both as-cast and solid-solution Mg-La (Ce) binary alloys gradually decreases with the increase in the added elements. However, after solution treatment, the thermal conductivity of the Mg-La (Ce) binary alloys is higher than that of the as-cast alloys. The addition of the Ce element helps refine the as-cast microstructure of the Mg-0.5Mn alloy. With the increase in Ce addition, the volume fraction of the Mg12Ce phase also increases. The thermal conductivity of the as-cast Mg-0.5Mn-xCe alloy gradually increases with rising temperature. Meanwhile, at room temperature, the thermal conductivity of the as-cast Mg-0.5Mn alloy gradually decreases with the increase in Ce addition, and the rate of decline gradually slows down due to the precipitation of the Mg12Ce phase. Full article