Search Results (753)

In recent years, biofuels and bioenergy derived from algae have gained increasing attention, fueled by the growing demand for renewable energy sources and the urgent need to lower CO₂ emissions. This research examines the generation of bioethanol and biomethane using freshly harvested and sedimented algal biomass. Employing a factorial experimental design, various trials were conducted, with ethanol yield as the primary optimization target. The findings indicated that the sodium hydroxide concentration during pretreatment and the amylase dosage in enzymatic hydrolysis were key parameters influencing the ethanol production efficiency. Under optimized conditions—using 0.3 M NaOH, 25 μL/g starch, and 250 μL/g cellulose—fermentation yielded ethanol concentrations as high as 2.75 ± 0.18 g/L (45.13 ± 2.90%), underscoring the significance of both enzyme loading and alkali treatment. Biomethane potential tests on the residues of fermentation revealed reduced methane yields in comparison with the raw algal feedstock, with a peak value of 198.50 ± 25.57 mL/g volatile solids. The integrated process resulted in a total energy recovery of up to 809.58 kWh per tonne of algal biomass, with biomethane accounting for 87.16% of the total energy output. However, the energy recovered from unprocessed biomass alone was nearly double, indicating a trade-off between sequential valorization steps. A comparison between fresh and dried feedstocks also demonstrated marked differences, largely due to variations in moisture content and biomass composition. Overall, this study highlights the promise of integrated algal biomass utilization as a viable and energy-efficient route for sustainable biofuel production. Full article

Sweet potato is a valuable root due to its nutritional benefits, health-promoting properties, and technological applications. The peel, often discarded during food processing, can be employed in the food industry, supporting a circular economy. Purple sweet potato peel (PSPP) is rich in anthocyanins, which can be used as natural colourants and antioxidants. Optimising their extraction can enhance yield and reduce costs. The current work aimed to optimize anthocyanin and antioxidant recovery from PSPP using a Box-Behnken design and sonotrode ultrasound-assisted extraction (sonotrode-UAE). Three independent variables were analysed: extraction time (2–6 min), ethanol concentration (35–85%), and liquid-to-solid ratio (10–30 mL/g). The dependent variables included total monomeric anthocyanin content (TMAC), individual anthocyanins, and antioxidant activity. TMAC in 15 extracts ranged from 0.16 to 2.66 mg/g PSPP. Peonidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside was the predominant anthocyanin. Among four antioxidant assays, Ferric-reducing antioxidant power (FRAP) showed the highest value. Ethanol concentration significantly influenced anthocyanin and antioxidant recovery (p < 0.05). The model demonstrated adequacy based on the coefficient of determination and variation. Optimal extraction conditions were 6 min with 60% ethanol at a 30 mL/g ratio. Predicted values were validated experimentally (coefficient of variation <10%). In conclusion, PSPP is a promising matrix for obtaining anthocyanin-rich extracts with antioxidant activity, offering potential applications in the food industry. Full article

Despite being recognized as toxic in anaerobic systems, sulfide’s potential to enhance hydrogen fermentation via microbial modulation remains underexplored. This study evaluated the combined effects of sulfide concentration (0–800 mg S/L) and heat pretreatment on hydrogen production during dark fermentation (DF). Without pretreatment, hydrogen yield reached 83 ± 2 mL/g COD at 0 mg S/L but declined with increasing sulfide, becoming negligible at 800 mg S/L. In contrast, heat-pretreated inocula showed markedly improved performance: peak cumulative production (4628 ± 17 mL) and yield (231 ± 1 mL/g COD) were attained at 200 mg S/L, while the maximum production rate (1462 ± 64 mL/h) occurred at 400 mg S/L. These enhancements coincided with elevated acetic and butyric acids, indicating a metabolic shift toward hydrogen-producing pathways. The microbial analysis of heat-pretreated samples revealed an enrichment of Clostridium butyricum (from 73.1% to 87.5%) and Clostridium perfringens, which peaked at 13.5% at 400 mg S/L. This species contributed to butyric acid synthesis. At 800 mg S/L, Clostridium perfringens declined sharply to 0.6%, while non-hydrogenogenic Levilinea saccharolytica proliferated, correlating with reduced butyric acid and hydrogen output. These findings indicate that sulfide supplementation, when combined with heat pretreatment, selectively restructures microbial communities and metabolic pathways, enhancing DF performance. Full article

Amidst the escalating global challenges of deforestation and climate change, effective forest governance has become a critical global imperative. As a key actor in this arena, China presents a crucial case for understanding state-led environmental governance. This study addresses the thematic evolution and governance structure of China’s forest policy planning from 1980 to 2024. Grounded in multi-level governance (MLG) theory, we apply the Non-negative Matrix Factorization (NMF) topic model to a corpus of 1265 policy documents sourced from the PKULaw database, spanning four administrative levels from central to county. An analysis of 13 core policy themes reveals a significant transition, shifting from early regulatory development and resource utilization to a modern emphasis on ecological protection, scientific monitoring, financial support, and governance innovation. The findings delineate a complex governance architecture: a vertical division of labor (central guidance, local implementation), a horizontal model of inter-departmental interaction where specialized management coexists with comprehensive coordination, and adaptive governance reflecting regional heterogeneity. These results illuminate the dynamic evolution of power allocation, central–local relations, and synergy within China’s forest sector. This study not only provides new empirical evidence and an analytical framework for understanding China’s natural resource policy transition but also offers scientific insights for optimizing multi-level forest governance systems and enhancing policy synergy and efficacy. Full article

Currently, the Longmaxi shale in the Sichuan Basin is the most successful stratum of shale gas production in China. However, because Longmaxi shale mostly has high over-maturity, a low-maturity sample cannot be obtained for gas generation thermal simulations, and as a result, a gas generation model has not yet been established for it. Therefore, models of other shales are usually used to calculate the amount of gas generated from Longmaxi shale, but they may produce inaccurate results. In this study, a Longmaxi shale sample with an equivalent vitrinite reflectance calculated from Raman spectroscopy (EqVR_o) of 1.26% was obtained from Well Yucan 1 in the Chengkou area, northeast Sichuan Province. This Longmaxi shale may have the lowest maturity in nature. Pyrolysis simulations based on gold tubes were performed on this sample, and the gas generation line was obtained. The amount of gas generated during the low-maturity stage was compensated by referring to gas generation data obtained from Lower Silurian black shale in western Lithuania. Thus, a gas generation model of the Longmaxi shale was built. The model showed that the gas generation process of Longmaxi shale could be divided into three stages: (1) First, there is the quick generation stage (EqVR_o 0.5–3.0%), where hydrocarbon gases were generated quickly and constantly, and the generation rate was steady. A maximum of 458 mL/g TOC was reached at a maturity of 3.0% EqVR_o. (2) Second, there is the stable stage (EqVR_o 3.0–3.25%), where the amount of generated gas reached a plateau of 453–458 mL/g TOC. (3) Third, there is the rapid descent stage (EqVR_o > 3.25%), where the amount of generated gas started to decrease, and it was 393 mL/g TOC at an EqVR_o of 3.34%. This model allows us to more accurately calculate the amount of gas generated from the Longmaxi shale in the Sichuan Basin. Full article

This study aimed to evaluate the effect of including silage from devilfish waste (SF-Hypostomus plecostomus) and probiotics (PB-Pediococcus acidilactici BX-B122 and Bacillus coagulans BX-B118) in ruminants on greenhouse gas production. The diets evaluated contained 0, 8, 14 and 20% of silage made from SF and the addition of PB at a dose of 0.2 mL/g of diet, using steers and sheep (rams) as rumen inoculum donors in a completely randomized statistical design with a 2 × 4 × 2 factorial arrangement. Asymptotic gas production (GP) was influenced (p < 0.01) by the interactions between rumen liquor (RL), SF, and PB. The inclusion of SF and PB resulted in a higher (p < 0.01) GP rate in sheep; however, the values were reduced with increasing levels of SF. Asymptotic CH₄ in the rumen fluid of steers decreased with an increasing SF percentage up to 14%. Probiotics had different effects on the rumen fluid of sheep and steers. In steers, probiotics substantially reduced (p < 0.01) CH₄ synthesis while supplementation increased it in sheep rumen fluid. Similarly, diets with probiotics had higher CO formation (p < 0.05) in sheep and steer liquor. Similarly, CO decreased (p < 0.05) with increasing levels of SF. In the rumen fluid of sheep and steers, the probiotics were found to reduce H₂S, while there was an SF-dose-dependent decrease in H₂S concentration. The ruminal pH and dry matter digestibility of sheep were higher than in steers. It can be concluded that increasing SF levels generally reduced the total gas and CH₄ production, with probiotics further enhancing this reduction, especially in CH₄ per unit of gas. Full article

Hot water extraction (HE), enzyme-assisted hot water extraction (EAHE), ultrasonic-assisted extraction with NADES (UAE-NADES) and ultrasonic-assisted extraction with NADES and enzyme pretreatment (UAE-NADES-E) were employed to extract polysaccharides from Peucedani Decursivi Radix (PDR) and their structures were characterized for the first time. UAE-NADES-E was found to be the most effective extraction method, and the extraction process was optimized by Box–Behnken design (BBD)-response surface methodology (RSM) experiments. The optimal extraction process was determined by using a NADES system with a molar ratio of betaine to 1,3-butanediol of 1:3, a water content of 30%, a liquid/solid ratio of 40:1 mL/g, an ultrasound time of 30 min, an ultrasound temperature of 45 °C and an alcohol precipitation time of 6 h; the polysaccharide extraction yield reached 19.93%. Further, the structures of polysaccharides from PDR extracted by the above four methods were characterized by FT-IR, SEM, gel and anion-exchange chromatography. Eight monosaccharides were detected in the PDR polysaccharides extracted by the four methods. The PDR polysaccharides extracted by the UAE-NADES-E method had lower molecular weights compared with those extracted by the other methods. Moreover, the PDR polysaccharides exhibited obvious antioxidant activity, as revealed by DPPH, ABTS+ and hydroxyl radical scavenging experiments, meaning they have the potential to be developed as natural antioxidants. Full article

Red sage (Salvia miltiorrhiza Bunge) is a perennial herb containing various bioactive compounds that promote human health. In this study, single-factor experiments were first conducted, followed by the optimization of extraction conditions to maximize the saponin content from red sage root extracts. In the single-factor experiments, the highest saponin content (47.5 ± 0.88 mg/g) was obtained using 80% ethanol, a solvent-to-material ratio of 40:1 (mL/g), an extraction period of 3 h, and an extraction temperature of 60 °C. Response Surface Methodology (RSM) was performed to optimize the extraction parameters with a material-to-solvent ratio of 41.31:1 (mL/g), an extraction temperature of 58.08 °C, and an extraction time of 3.16 h. Under these optimized conditions, the experimental saponin content reached 47.71 ± 0.15 mg/g. Additionally, crude extract of red sage exhibited antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals with an IC₅₀ value of 16.24 µg/mL. This extract also demonstrated anticancer against 61.79 ± 3.57% HepG2 cancer cells at a concentration of 100 µg/mL. Full article

Rare earth elements (REEs) have garnered significant global attention due to their essential role in advanced technologies. Sri Lanka is endowed with various REE-bearing minerals, including the apatite-rich deposit in the Eppawala area, commonly known as Eppawala rock phosphate (ERP). However, direct extraction of REEs from ERP is technically challenging and economically unfeasible. This study introduces a novel, integrated approach for recovering REEs from ERP as a by-product of nitrophosphate fertilizer production. The process involves nitric acid-based acidolysis of apatite, optimized at 10 M nitric acid for 2 h at 70 °C with a pulp density of 2.4 mL/g. During cooling crystallization, 42 wt% of calcium was removed as Ca(NO₃)₂.4H₂O while REEs remained in the solution. REEs were then selectively precipitated as REE phosphates via pH-controlled addition of ammonium hydroxide, minimizing the co-precipitation with calcium. Further separation was achieved through selective dissolution in a sulfuric–phosphoric acid mixture, followed by precipitation as sodium rare earth double sulfates. The process achieved over 90% total REE recovery with extraction efficiencies in the order of Pr > Nd > Ce > Gd > Sm > Y > Dy. Samples were characterized for their phase composition, elemental content, and morphology. The fertilizer results confirmed the successful production of a nutrient-rich nitrophosphate (NP) with 18.2% nitrogen and 13.9% phosphorus (as P₂O₅) with a low moisture content (0.6%) and minimal free acid (0.1%), indicating strong agronomic value and storage stability. This study represents one of the pioneering efforts to valorize Sri Lanka’s apatite through a novel, dual-purpose, and circular approach, recovering REEs while simultaneously producing high-quality fertilizer. Full article

The widely utilized TiO₂ nanoparticles (NPs) tend to accumulate in wastewater and affect microbial growth. This work investigated the impacts of prolonged TiO₂ NP addition to filamentous aerobic granular sludge (AGS) using two identical sequencing batch reactors (SBRs, R1 and R2). R1 (the control) had no TiO₂ NP addition. In this reactor, filamentous bacteria from large AGS grew rapidly and extended outward, the sludge volume index (SVI₃₀) quickly increased from 41.2 to 236.8 mL/g, mixed liquid suspended solids (MLSS) decreased from 4.72 to 0.9 g/L, and AGS disintegrated on day 40. Meanwhile, the removal rates of COD and NH₄⁺-N both exhibited significant declines. In contrast, 5–30 mg/L TiO₂ NPs was added to R2 from day 21 to 100, and the extended filamentous bacteria were effectively controlled on day 90 under a 30 mg/L NP dosage, leading to significant reductions in COD and NH₄⁺-N capabilities, particularly the latter. Therefore, NP addition was stopped on day 101, and AGS became dominant in R2, with an SVI₃₀ and MLSS of 48.5 mL/g and 5.67 g/L on day 130. COD and NH₄⁺-N capabilities both increased to 100%. Microbial analysis suggested that the dominant filamentous bacteria—Proteobacteria, Bacteroidetes, and Acidobacteria—were effectively controlled by adding 30 mg/L TiO₂ NPs. XRF analysis indicated that 11.7% TiO₂ NP accumulation made the filamentous bacteria a framework for AGS recovery and operation without NPs. Functional analysis revealed that TiO₂ NPs had stronger inhibitory effects on nitrogen metabolism compared to carbon metabolism, and both metabolic pathways recovered when NP addition was discontinued in a timely manner. These findings offer critical operational guidance for maintaining the stable performance of filamentous AGS systems treating TiO₂ NP wastewater in the future. Full article

To obtain actionable information for humanitarian and other emergency responses, an accurate classification of news or events is critical. Daily news and social media are hard to classify based on conveyed information, especially when multiple categories of information are embedded. This research used large language models (LLMs) and traditional transformer-based models, such as BERT, to classify news and social media events using the example of the Sudan Conflict. A systematic evaluation framework was introduced to test GPT models using Zero-Shot prompting, Retrieval-Augmented Generation (RAG), and RAG with In-Context Learning (ICL) against standard and hyperparameter-tuned bert-based and bert-large models. BERT outperformed GPT in F1-score and accuracy for multi-label classification (MLC) while GPT outperformed BERT in accuracy for Single-Label classification from Multi-Label Ground Truth (SL-MLG). The results illustrate that a larger model size improves classification accuracy for both BERT and GPT, while BERT benefits from hyperparameter tuning and GPT benefits from its enhanced contextual comprehension capabilities. By addressing challenges such as overlapping semantic categories, task-specific adaptation, and a limited dataset, this study provides a deeper understanding of LLMs’ applicability in constrained, real-world scenarios, particularly in highlighting the potential for integrating NLP with other applications such as GIS in future conflict analyses. Full article

The mineral processing of a low-grade tungsten-molybdenum ore (LGTMO) was investigated to assess the potential of recovering molybdenum (Mo) and tungsten (W). Techniques such as Polarizing Microscope (PM), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Mineral Liberation Analysis (MLA), and Advanced Mineral Identification and Characterization System (AMICS) were employed. The recoverable metals in the ore are Mo (0.158% ± 0.03%) and W (0.076% ± 0.02%). Mo exists in two forms: 63.30% as molybdenite and 36.7% as powellite (CaMo_xW_1−xO₄). W is present as 75.26% scheelite and 24.74% powellite. The complete dissociation rates of molybdenite and scheelite-powellite are 27.14% and 88.87%, respectively. Particles of scheelite-powellite with a diameter less than 10 µm account for 34.61%, while molybdenite particles with a diameter below 10 µm make up 72.73%. Scheelite-powellite is mainly associated with olivine and dolomite, while molybdenite is mainly associated with pyroxene, calcite, and hornblende. Based on the process mineralogy, the mineralogical factors influencing the flotation recovery of molybdenite and scheelite-powellite were analyzed. Finally, a complete hydrometallurgical leaching test was carried out. The optimal experimental conditions are as follows: liquid-solid ratio of 6 mL/g, KMnO₄ concentration of 0.015 mol/L, Na₂CO₃ concentration of 0.12 mol/L, NaHCO₃ concentration of 0.024 mol/L, leaching time of 4 h, and leaching temperature of 85 °C. Under these conditions, the leaching efficiencies of Mo and W reach 79.23% and 41.41%, respectively. This study presents a novel approach for the recovery of refractory W and Mo resources in LGTMO while simultaneously providing a theoretical basis for the high-efficiency utilization of these resources. Full article

This work aims to study the catalytic properties of Fe, Cr, and Cu catalysts deposited on chitosan–silica (SBA-15) composites in liquid phase oxidation of cyclohexane (CH) with H₂O₂ and photocatalytic hydrogen evolution reaction. The catalysts were obtained by consecutive adsorption of chitosan (CS) and metal ions (Fe³⁺, Cr³⁺, Cu²⁺) on SBA-15 at ambient conditions. Characterization of the catalysts by XRD, IR spectroscopy, XPS, TEM, SEM, etc., showed the CS and metal ion adsorption on the solid support. Modification with CS provided better immobilization of the metal ions on SBA-15. The synthesized catalysts demonstrated different performance in liquid phase oxidation of cyclohexane with H₂O₂ under mild conditions at 40 °C and atmospheric pressure. Cyclohexane conversion on Fe–CS/SBA-15 (18.5%) and Cr–CS/SBA-15 (21.6%) was higher than on Cu–CS/SBA-15 (9.3%). The influence of different conditions of the reaction such as time, temperature, catalyst dosage, substrate and oxidant ratio on cyclohexane conversion in the presence of the most efficient Cr–CS/SBA-15 catalyst was also studied. The optimal reaction conditions were found to be the following: duration of reaction—4 h, temperature of reaction—50 °C, m_cat—0.03 g, a substrate/H₂O₂ ratio of 1:3. In addition, Cr–CS/SBA-15 and Fe–CS/SBA-15 catalysts were studied in a photocatalytic H₂ evolution reaction. The Fe-containing catalyst demonstrated superior efficiency in photocatalytic H₂ evolution. The total volume of hydrogen produced within 3 h was 103 mL/g. Thus, this study demonstrates that chitosan possesses promising potential in the design of the supported catalysts for cyclohexane oxidation and photocatalytic hydrogen evolution reactions. Full article

The Ni/SiO₂ and the ceria-promoted Ni-CeO₂/SiO₂ were prepared by the impregnation method and co-impregnation method, respectively. The performance of the carbon dioxide reforming of methane (CDR) over Ni/SiO₂ and Ni-CeO₂/SiO₂ was investigated under the conditions of CH₄/CO₂ = 1.0, T = 800 °C, and GHSV = 60,000 mL·g⁻¹·h⁻¹. As a result, a high CDR performance, especially stability, was obtained over Ni-CeO₂/SiO₂, in which the conversion of CH₄ was very similar to that of the thermodynamic equilibrium (88%), and a negligible decrease in CH₄ conversion was observed after 50 h of the CDR reaction. Ni/SiO₂ and Ni-CeO₂/SiO₂ before and after the CDR reaction were subjected to structural characterization by XRD, TEM, TG–DSC, and physical adsorption. It was found that the addition of CeO₂ into Ni/SiO₂ significantly affected its surface area, the size and dispersion of Ni, the reduction behavior, and the coking properties. Moreover, the redox property of Ce³⁺-Ce⁴⁺, which accelerates the gasification of the coke, made Ni-CeO₂/SiO₂ successfully operate for 50 h without observable deactivation. Thus, the developed catalyst is very promising for the CDR. Full article

Distillers grains are the main by-products of the brewing industry, with a large output but a low degree of resource utilization. Exploring more efficient comprehensive utilization technologies for distillers grains is of great significance for increasing the added value of the brewing industry. This study took Moutai distillers grains as the research object, and the ultrasonic-assisted extraction process of crude flavonoids from distillers grains was first optimized. On this basis, the in vitro antioxidant and anti-inflammatory effects of the crude flavonoid extract were further explored. The results show that the optimal process parameters for ultrasonic-assisted extraction of crude flavonoids were an ethanol concentration of 95%, liquid-to-solid ratio of 26 mL/g, and ultrasonic time of 36 min (with a fixed ultrasonic power of 500 W). Under such conditions, the yield of crude flavonoid extract from Moutai distillers grains was 25.39% ± 5.05%. In vitro antioxidant results showed that 2 mg/mL of crude flavonoid extract had good DPPH and ABTS free radical scavenging activities (78.17% and 75.21%, respectively). In vitro anti-inflammatory results showed that 0.5% crude flavonoid extract (the survival rate of HaCaT cells treated with this concentration was greater than 80%) significantly reduced the secretion of the inflammatory factors IL-6 and IL-1β induced by TNF-α and IFN-γ. In summary, this study showed that Moutai distillers grains may provide easily accessible and inexpensive raw materials for the functional food and cosmetic industries. Full article