Search Results (6,684)

Hydrotreated vegetable oil (HVO) is a second-generation biofuel with physicochemical properties similar to conventional diesel. Composed mainly of n-paraffins, it offers favorable autoignition characteristics. Produced by hydrotreating vegetable oils or animal fats, including waste sources such as used cooking oil, HVO contributes to lower greenhouse gas emissions and waste utilization. Thanks to its similarity to diesel, it can be used directly or in blends without engine modifications. Blending reduces fossil fuel use and pollutant emissions while maintaining engine performance. This study investigates the autoignition behavior of diesel, neat HVO, and HVO–diesel blends containing 25%, 50%, and 75% HVO by volume. Experiments were conducted in a constant-volume combustion chamber at 550 °C and 650 °C to simulate engine-relevant conditions. Autoignition quality was assessed using ignition delay, combustion delay, average and maximum pressure rise rate, maximum pressure rise, apparent heat release rate, and derived cetane number. The results show that higher HVO content increases the sensitivity of ignition delay, combustion delay, and average pressure rise rate to lower chamber temperature. In addition, a linear increase in derived cetane number was observed with increasing HVO concentration, providing new insights into ignition and combustion behavior of renewable fuel blends. Full article

Tambatinga (Colossoma macropomum × Piaractus brachypomus), a hybrid Amazonian fish recognized for its superior growth performance, represents a valuable and sustainable source of collagen-rich raw material. Due to its tropical origin, the species’ skin may contain higher levels of amino acids, which can enhance the functional and structural properties of gelatin derived from it. The valorization of fish processing residues for biopolymer production not only mitigates environmental impacts but also reinforces the principles of the circular economy within aquaculture systems. This study explores the development of biopolymer films from Tambatinga skin, an abundant by-product of Brazilian aquaculture. The skins were cleaned and subjected to a hot water–acid extraction process to obtain gelatin. The extracted gelatin exhibited high proline and hydroxyproline contents (12.47 and 9.84 g/100 g of amino acids, respectively) and a Bloom strength of 263.9 g, confirming its suitability for film formation. Films were prepared using 2 g of gelatin per 100 g of film-forming solution, with glycerol added at 10 and 20 g/100 g of gelatin. The resulting films were transparent, flexible, and showed uniform surfaces. Increasing the glycerol concentration reduced tensile strength (from 59.4 to 37.9 MPa) but improved elongation at break (from 116% to 159.1%) and modified the films’ thermal behavior. Moreover, Tambatinga gelatin films demonstrated excellent UV-blocking performance (below 300 nm) and lower water vapor permeability compared to other gelatin-based films reported in the literature. These findings highlight the potential of fish skin—typically regarded as industrial waste—as a renewable and high-value raw material for the production of sustainable biopolymers. This approach supports resource efficiency, waste reduction, and the broader goals of sustainable development and circular bioeconomy. Full article

During cocoa processing, approximately ten times more cacao pod husk (CPH) waste is generated than cacao beans. Due to its high lignocellulosic content, CPH is an alternative feedstock for the production of fermentable sugars and bioproducts. In this study, CPH enzymatic hydrolysates were used as a carbon source to produce Lacticaseibacillus biosurfactants. CPH was subjected to alkaline pretreatment followed by enzymatic hydrolysis using the commercial enzyme cocktail Cellic Ctec2. The resulting hydrolysates were used to formulate culture media for growing Lacticaseibacillus rhamnosus and Lacticaseibacillus casei. Cell growth and the activity of extracellular and cell-bound biosurfactants were evaluated. The highest glucose concentration in the hydrolysates (11.45 g/L) was achieved using 15% (w/v) solids loading of alkaline-pretreated CPH and an enzymatic load of 20 FPU/g CPH over 3 h. The maximum emulsification index (E24) was 60%, observed with the extracellular biosurfactant from L. rhamnosus cultured in CPH-based medium without supplementation. L. casei extracellular biosurfactants were effective at inhibiting Pseudomonas aeruginosa PA14 biofilm formation (39–45%) in CPH-based media supplemented with peptone, yeast extract, and both nutrients. These findings highlight the potential of CPH enzymatic hydrolysates as a sustainable carbon source for biosurfactant production with emulsification and antibiofilm activity, contributing to the valorization of cocoa agro-industrial waste. Full article

This systematic review aims to describe the current state of research on soil remediation utilizing digestates inoculated with fungi, as a cost-effective alternative. This study was performed according to the PRISMA 2020 guidelines, and nine papers were finally selected for review. The application of digestates augments the soil microbial community in terms of bacterial strains, mycorrhizal colonization, and enzymes. Digestates inoculated with fungi have notable impacts on soil stabilization. Some authors reported an improvement of up to 100% in plant growth when using digestates. HM removal rates of 17% for Si, 40% for Cd, and up to 80% for Pb have been achieved. Antibiotics and PFCAs showed low or no accumulation. The biomass source used for anaerobic digestion has a very important impact on the resulting digestate’s quality and effect in soils: the use of cattle manure resulted in an increase in biomass yield from 9% up to 100% when compared to manure co-digested with organic wastes. The fungal strain, environmental conditions, and existing contaminants must be considered with respect to the specific practical application. These insights can contribute to the management of environmental risks and the prevention of negative impacts on human health, ecosystems, and the economy. Full article

Railway hazardous chemical transportation, a high-risk activity that endangers personnel, infrastructure, and ecosystems, directly undermines the sustainability of the transportation system and regional development. Traditional risk management algorithms, which rely on empirical rules, result in sluggish emergency responses (with an average response time of 4.8 h), further exacerbating the environmental and economic losses caused by accidents. The standalone DBSCAN algorithm only supports static spatial clustering (with unoptimized hyperparameters); it lacks probabilistic reasoning capabilities for dynamic scenarios and thus fails to support sustainable resource allocation. To address this gap, this study develops a DBSCAN–Bayesian network fusion model that identifies risk hotspots via static spatial clustering—with ε optimized by the K-distance method and MinPts determined through cross-validation—for targeted prevention; meanwhile, the Bayesian network quantifies the dynamic relationships among “hazardous chemical properties-accident scenarios-material requirements” and integrates real-time transportation and environmental data to form a “risk positioning-demand prediction-intelligent allocation” closed loop. Experimental results show that the fusion algorithm outperforms comparative methods in sustainability-linked dimensions: ① Emergency response time is shortened to 2.3 h (a 52.1% improvement), with a 92% compliance rate in high-risk areas (e.g., water sources), thereby reducing ecological damage. ② The material satisfaction rate reaches 92.3% (a 17.6% improvement), and the neutralizer matching accuracy for corrosive leaks is increased by 26 percentage points, which cuts down resource waste and lowers carbon footprints. ③ The coverage rate of high-risk areas reaches 95.6% (a 16.4% improvement over the standalone DBSCAN algorithm), with a 27.5% reduction in dispatch costs and a drop in resource waste from 38% to 11%. This model achieves a leap from static to dynamic decision-making, providing a data-driven paradigm for the sustainable emergency management of railway hazardous chemicals. Its “spatial clustering + probabilistic reasoning” path holds universal value for risk control in complex systems, further boosting the sustainability of infrastructure. Full article

Seafood-derived carbonate waste, primarily calcium carbonate (CaCO₃), has attracted growing interest for sustainable reuse, yet the unique potential of aged biogenic sources remains underexplored. Blue crab (Callinectes sapidus) shells are particularly distinctive: they consist of Mg-calcite with an intrinsic 3D-porous structure and naturally embedded astaxanthin, a potent antioxidant not found in other calcite- or aragonite-based residues. While organic degradation over time is often assumed to compromise functionality, this study demonstrates that five-years-aged crustacean shell waste retains both its crystallinity and bioactive carotenoids after calibrated ball milling. Across four powder batches produced under distinct milling conditions by varying frequencies and durations, dynamic light scattering confirmed only subtle particle size variation, while Raman spectroscopy, XRD, FT-IR, and SEM-EDX confirmed structural and chemical integrity and highlighted the subtle amorphization induced by slightly different milling parameters, which, in turn, driven to slightly different conversion efficiency into phosphate mineral. Strikingly, all powders underwent rapid transformation into dicalcium phosphate dihydrate (brushite) enriched with carotenoids upon reaction with phosphoric acid. This work reveals, for the first time, that years-aged biogenic Mg-calcite waste not only preserves its naturally embedded carotenoids but also offers a direct route to functional phosphate composites, establishing its untapped value in environmental and biomedical applications. Full article

The Organic Rankine Cycle (ORC)-based waste-heat recovery system represents an important technological pathway toward decarbonization in the maritime industry. This study focuses on the design and optimization of a multi-heat-source Organic Rankine Cycle (MHSORC) power generation system specifically developed for large marine diesel engines, which simultaneously utilizes exhaust gas, cylinder jacket water, and scavenging air as heat sources. Unified thermodynamic, economic, and environmental models are constructed to evaluate the coupled performance of the system.Eight low GWP working fluids are assessed, and a multi-objective optimization is performed to balance efficiency, cost, and environmental impact. The optimal design point is subsequently identified using a decision-making algorithm. The results indicate that, for the MHSORC, higher evaporating temperatures and lower condensing temperatures improve system performance, and the heat-source temperature exerts a direct and substantial influence on that performance. Among the candidate fluids, R601 exhibits the best overall performance, whereas R1234ze performs the worst. With R601 as the working fluid, the MHSORC achieves an exergy efficiency of 41.69%, a LCOE of 0.0495 $/kWh, and greenhouse gas emissions of 0.8019 kt of CO_2,eq. Full article

Background/objectives: Antimicrobial resistance (AMR) is a growing public health concern, and misuse of antibiotics in livestock farming contributes to its emergence. In Blantyre, Malawi, small-scale pig and poultry farming is widespread, but the knowledge, attitudes, and practices (KAP) driving antimicrobial use (AMU) remain poorly understood. This study aimed to assess the KAP regarding AMU and manure management among pig and poultry farmers in Blantyre, Malawi. Methods: This cross-sectional study surveyed 118 randomly selected farmers to assess AMU patterns, sources of antibiotics, adherence to withdrawal periods, disposal practices, and awareness of AMR and regulations. Data was collected using a structured questionnaire and analyzed with descriptive statistics and inferential tests (with statistical significance set at p < 0.05). Results: Antibiotic use was reported by 88% of farmers, primarily for therapy (93.3%) and prophylaxis (85.6%), including for viral diseases such as Newcastle disease in poultry and African swine fever in pigs. Oxytetracycline (91.5%), penicillin (50.8%), and trimethoprim-sulfamethoxazole (39.8%) were the most used antibiotics, predominantly sourced from agrovet shops (73.7%). While 61% of farmers knew antibiotic misuse could lead to AMR, significant gaps were observed: 68.6% had no formal training, 55.9% were unaware of regulations, and 42% sold/consumed products before the end of the withdrawal period. Most farmers disposed of expired antibiotics (80.5%) and packaging (92.4%) in household waste. Higher education and prior training were significantly associated with good knowledge. Conclusions: This study reveals significant knowledge–practice gaps and high-risk behaviors, such as misuse for viral diseases and unsafe disposal, that exacerbate AMR risks. Interventions must prioritize targeted farmer education, strengthening of veterinary extension services, and stricter regulation of agrovet shops to promote antimicrobial stewardship and support Malawi’s National Action Plan on AMR. Full article

Cationic polyelectrolytes, characterized by positively charged functional groups, play an essential role in industries ranging from food solutions, water treatment, medical, cosmetic, textiles and agriculture due to their electrostatic interactions, biocompatibility, and functional versatility. This paper critically examines the transition from petroleum-based synthetic polymers such as poly(diallyldimethylammonium chloride) and cationic polyacrylamides to sustainable natural alternatives derived from agri-forestry resources like starch derivatives and cellulose. Through a cradle-to-gate life cycle assessment, we highlight the superior renewability, biodegradability, and lower carbon footprint of bio-based polycations, despite challenges in agricultural sourcing and processing. This study examines cationization processes by comparing the environmental limitations of traditional chemical methods, such as significant waste production and limited scalability, with those of second-generation reactive extrusion (REX), which enables solvent-free and rapid modification. REX also allows for adjustable degrees of substitution and ensures uniform charge distribution, thereby enhancing overall functional performance. Groundbreaking research and optimization achieved through the integration of artificial intelligence and machine learning for parameter regulation and targeted mechanical energy management underscore REX’s strengths in precision engineering. By methodically addressing current limitations and articulating future advancements, this work advances sustainable innovation that contributes to a circular economy in materials science. Full article

Plastics play a pivotal role in various industries owing to their versatility in engineering their physical, mechanical, and chemical properties while exploiting their remarkable durability, light-weight nature, and cost-effectiveness. Yet, their widespread use has led to the pollution of Earth’s water systems. Over time, plastic waste degrades into microplastics, particles smaller than 5 mm. Recent studies have highlighted the growing concerns associated with microplastics, especially in bottled beverages, including bottled water, with associated hazards still in the very early stages of being fully understood. Furthermore, the global understanding of the extent of microplastic contamination in the environment and along the food chain remains limited. This study aimed to detect, quantify, and characterise microplastics in bottled drinking water produced and sold in Malta. Samples from five brands were filtered, stained with Nile red, and quantified using fluorescence microscopy. The average microplastic concentration was found to be 35,877 ± 23,542 particles per litre, with 84% of samples exhibiting contamination, which was noted to be statistically significant. The average particle diameter was measured to be 2.3696 ± 0.0035 µm. Raman spectroscopy was used to chemically characterise 10 larger particles per brand (i.e., 50 samples), identifying the presence of cellulose, polyurethane, polymethyl methacrylate, polyethylene, and smaller quantities of other polymers. Morphological analysis classified 36 of the larger particles as fragments and 14 as fibres. Excluding laboratory-introduced contamination, the primary source of microplastic contamination in the analysed bottled water was traced to the bottle caps. Full article

Understanding the occurrence and spatial variability of potentially toxic elements in soils is essential for tracing pollution origins, assessing ecological risks, and supporting sustainable land use management. This study investigates the soil pollution with Cd, Pb, Ni, Cu, Zn, Cr, As, Mn, Sr, and Fe, their spatial distribution, and environmental risks in two areas in southwestern Romania—Isverna and Tismana—using a combination of pollution indices and Geographic Information System (GIS)-based analyses. Results indicated predominantly low to moderate pollution across both areas, with localized hotspots of high to extreme pollution, particularly with Ni and Pb, near human settlements. In contrast, Tismana showed more uniform, generally lower pollution levels, suggesting the influence of natural (lithogenic) sources. Spatial distribution maps highlighted these differences, showing more heterogeneous localized hotspots in Isverna, likely linked to anthropogenic activities such as agricultural runoff and improper domestic waste disposal. The integrated use of pollution indices and GIS mapping proved effective in identifying contamination patterns and risk zones, providing valuable insights for environmental monitoring and sustainable management of rural land. Full article

Antibiotics have revolutionized medicine and animal production, yet their extensive use has accelerated the emergence and spread of antimicrobial resistance (AMR). Beyond clinical contexts, livestock and aquaculture are now recognized as major contributors to the global resistome. This review synthesizes evidence across cattle, poultry, swine, sheep and goats, and aquaculture, highlighting how antimicrobial usage shapes resistance at the human–animal–environment interface. A substantial proportion of administered drugs is excreted unmetabolized, leading to the accumulation of unmetabolized antimicrobial residues, antibiotic-resistant bacteria (ARB), and antibiotic resistance genes (ARGs) in soils, manures, waters, sediments, and air. These reservoirs function as long-term sources and dissemination pathways through runoff, leaching, bioaerosols, effluents, and biological vectors. Despite different production systems, similar ARG families dominate, particularly those conferring resistance to tetracyclines, sulfonamides, and β-lactams. Mobile genetic elements and co-selectors such as heavy metals, disinfectants, and microplastics reinforce their persistence. Aquaculture, where water serves both as habitat and vector, emerges as a critical hotspot, while small ruminant systems remain under-researched despite their importance in many low- and middle-income countries. This synthesis highlights convergent patterns across sectors: antimicrobial use drives ARG enrichment; manures, litters, sediments, and effluents act as persistent reservoirs; and dissemination routes connect farms, ecosystems, and human populations. Within a One Health framework, mitigation requires preventive strategies—vaccination, biosecurity, and optimized waste management—supported by harmonized stewardship policies and integrated environmental surveillance. Full article

Wastewater generated by academic institutions poses an environmental burden due to its composition, including household, food-related waste, and potential microcontaminants such as pharmaceutical and laboratory chemicals. This study evaluated wastewater from eleven academic institutions. Horizontal subsurface flow constructed wetlands (HSFCWs) filled with locally sourced volcanic gravel were tested for treatment performance at a selected site, the University of Rwanda, College of Science and Technology (UR-CST). Six HSFCWs operated continuously for four months: two planted with Cyperus latifolius, two with Juncus effusus, and two unplanted. Academic wastewater showed average concentrations of 715 mg/L COD, 54 mg/L NH₄⁺-N, 9 mg/L NO₃⁻-N, and 32 mg/L PO₄³⁻-P. A 4-day hydraulic retention time was effective for the treatment process. The HSFCWs achieved removal efficiencies of 69–82% (COD), 66–87% (NH₄⁺-N), 69–90% (NO₃⁻-N), and over 90% for TSS and PO₄³⁻-P, emphasizing the strong physical and chemical purification capacity of volcanic gravel as confirmed by XRF analysis. Juncus effusus outperformed Cyperus latifolius in biomass (6667 vs. 4389 g/m²) and nutrient assimilation per unit area, removing 3.75× more TP and 1.46× more TN. The desorption capacity of the substrate enabled potential phosphorus recovery of up to 50%. Volcanic gravel-based CWs offer an effective, low-cost, and sustainable approach to wastewater treatment with potential for nutrient recovery. Full article

Rambutan (Nephelium lappaceum) shell, an agro-industrial by-product, is a rich source of phenolic acids and minor anthocyanins, but its direct use is limited by instability and low bioavailability. We extracted phenolic-rich fractions and produced maltodextrin microcapsules by spray drying, then confirmed chemical entrapment and amorphization by FTIR, SEM, and XRD. The formulation showed high encapsulation efficiency and high antioxidant capacity (DPPH), selective bactericidal activity against Pseudomonas aeruginosa and Burkholderia cepacia, and strong inhibition of Staphylococcus aureus and Listeria monocytogenes biofilms, while exhibiting negligible hemolysis (<2%) across tested concentrations. Antitumor effects were moderate with low selectivity in vitro, indicating that phenolic-acid-driven redox modulation may require fractionation or delivery optimization for oncology applications. Overall, spray-dried microcapsules provided structural stability and safety while concentrating multifunctional activities relevant to food and biomedical uses. By valorizing a tropical waste stream into a bioactive, hemocompatible ingredient, this work aligns with societal goals on health and sustainable production (SDG 3 and SDG 12) and offers a scalable route to deploy underutilized phenolic resources. Full article

Satellite remote sensing has become an increasingly important approach for detecting and quantifying methane emissions across spatial and temporal scales. While most reviews in the literature have addressed aspects of methane monitoring, they often focus primarily on satellite platforms or provide discussions on retrieval methodologies. This review offers an integrated assessment of recent developments in satellite-based methane detection, combining technical evaluations of satellite instruments with detailed analysis of retrieval techniques and sector-specific applications. The paper distinguishes between area flux mappers and point-source imagers and reviews both established and recent satellite missions, including GHGSat, MethaneSAT, and PRISMA. Retrieval methods are critically compared, covering full-physics models, CO₂ proxy approaches, optimal estimation, and emerging data-driven techniques such as machine learning. The review further examines methane emission characteristics in key sectors, i.e., oil and gas, coal mining, agriculture, and waste management, and discusses how satellite data are applied in emission estimation and mitigation contexts. The paper concludes by identifying technical and operational challenges and outlining research directions to enhance the accuracy, accessibility, and policy relevance of satellite-based methane monitoring. Full article