Search Results (15,091)

The increasing contamination of agricultural soils with microplastics (MPs) represents an emerging environmental challenge. While conventional plastics such as low-density polyethylene (LDPE) persist for decades, biodegradable alternatives like polybutylene adipate terephthalate (PBAT) are promoted as eco-friendly solutions. However, their environmental safety for crop plants and soil microbiota remains poorly understood. In this study, we evaluated the effects of LDPE and PBAT microplastics (1% w/w) on the growth and physiological state of winter wheat (Triticum aestivum L.) cultivated in soil, either alone or in combination with the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and the plant-beneficial fungus Trichoderma citrinoviride. Growth parameters (root and shoot length and mass), germination index, chlorophyll content, antioxidant enzyme activity, and lipidomic profiles of wheat were assessed. PBAT stimulated biomass accumulation but simultaneously triggered oxidative stress and remodeled membrane phospholipids, indicating physiological disturbance. T. citrinoviride enhanced wheat growth and mitigated oxidative stress under non-contaminated conditions; however, its beneficial effect was generally suppressed in the presence of PBAT and/or 2,4-D. The results suggest that, despite its biodegradability, PBAT may pose a higher phytotoxic potential than conventional LDPE, particularly by altering oxidative balance and membrane lipid composition in wheat. Full article

Z-cut lithium niobate single crystal demonstrates considerable promise for contact-based ultrasonic nondestructive testing and structural health monitoring (SHM) transducers due to its high piezoelectric coefficients, strong electromechanical coupling capability, and environmentally friendly lead-free composition. As a simulation-based theoretical exploration, this study systematically investigates the impact of gap spacing and electrode width in concentric ring configurations on the resonant characteristics and pulse-echo response of ultrasonic transducers by establishing a parametrized finite element model. Numerical simulations reveal that electrode geometry plays a critical role in determining both the effective electromechanical coupling coefficient and echo signal strength. Optimizing the electrode ring width achieved an effective electromechanical coupling coefficient (<!-- MathType@Translator@5@5@MathML2 (no namespace).tdl@MathML 2.0 (no namespace)@ --> Full article

Zeolite imidazolate frameworks (ZIFs)-derived carbon materials have garnered widespread attention as peroxymonosulfate (PMS) activators in removing antibiotics because of their excellent catalytic performance. However, most carbon materials derived from ZIFs exhibit limited efficacy in treating high-concentration (>10 ppm) antibiotic wastewater, and their synthesis methods are environmentally unfriendly. Herein, we develop a simple and environmentally friendly preparation method to synthesize a new type of nitrogen-doped carbon-supported carbon nanotubes coated with cobalt nanoparticle (Co-CNTs@NC) composites via high-temperature calcination of cobalt–zinc bimetallic ZIFs. The material characterization results confirm the successful preparation of Co-CNTs@NC composites featuring a high specific surface area (512.13 m²/g) and a Co content of 5.38 wt%. Across an initial pH range of 3.24–9.00, the Co-CNTs@NC/PMS catalytic system achieved over 84.17% degradation of 20 mg/L tetracycline hydrochloride within 90 min, demonstrating its favorable pH tolerance. The singlet oxygen-dominated degradation mechanism was confirmed by quenching experiments and electron paramagnetic resonance characterization. This work can provide technical guidance and reference significance for the preparation of metal–carbon materials derived from ZIFs with excellent efficiency of removal of high-concentration antibiotics. Full article

This paper presents a numerical study on the deployment of Overfire Air (OFA) technology in coal-fired thermal power plants in Kazakhstan to reduce harmful emissions. The simulation utilized a digital model of the combustion chamber of the BKZ-75 boiler at Shakhtinsk thermal power plant, which utilizes high-ash Karaganda coal containing 35.10% ash. During the development of two-stage combustion technology, different methods of supplying extra air via OFA injectors were examined. Various positions within the combustion chamber were evaluated for their placement: at heights of h = 0.165 m; 0.75 m; 1.375 m; 2.25 m; 2.5 m; 8 m; 9.4 m; 10 m; 11 m; and 12 m. The baseline combustion mode (OFA = 0%) and several additional air injector settings were analyzed, including OFA levels of 5%, 10%, 15%, 18%, 20%, 25%, and 30% of the total air volume. Numerical simulations generated temperature distributions along with carbon monoxide (CO) and nitrogen (NO) concentration fields, both inside and outside the combustion chamber outlet. Research indicates that the most effective reduction in pollutant emissions happens when OFA injectors are positioned at 9.4 m and supply supplementary air at an OFA rate of 18%. Under these settings, the carbon monoxide concentration at the combustion chamber outlet decreases by approximately 36%, while nitrogen oxide levels drop by 25%, compared to the baseline condition (OFA = 0%). These insights can be utilized to upgrade boiler units, promoting cleaner fuel combustion in coal-fired thermal power plants. Full article

The widespread use of antibiotics in human medicine, veterinary care, and livestock production has resulted in their frequent detection in diverse environmental and food matrices, making continuous surveillance of antibiotic residues in food products essential for consumer protection. In this study, a sustainable analytical method based on dispersive liquid–liquid microextraction (DLLME) coupled with UHPLC–MS/MS was developed for the trace determination of sulfamethoxazole, sulfadimethoxine, and enrofloxacin in commercial cow milk and chicken eggs. A natural deep eutectic solvent (NADES) composed of anisaldehyde and octanoic acid (2:1, molar ratio) was employed as a biodegradable extraction solvent, and key extraction parameters were systematically optimized. Under optimized conditions, the method demonstrated excellent linearity (R² ≥ 0.9982), recoveries of 89.5–98.7%, and RSDs ≤ 6.04%. Application to 44 commercial samples from the Saudi market revealed sulfamethoxazole as the most frequently detected antibiotic, occurring in 90% of egg samples (2.17–13.76 µg kg⁻¹) and 70.8% of milk samples (0.26–26.67 µg L⁻¹). A comprehensive evaluation using ten metrics confirmed the method’s greenness, practicality, analytical performance, and innovation. Overall, the proposed NADES–DLLME–UHPLC–MS/MS approach offers a rapid, cost-effective, and environmentally friendly alternative for routine monitoring of antibiotic residues in food matrices. Full article

A well-designed layout for urban parks plays a crucial role in constructing livable cities and enhancing residents’ well-being. The provision of age-friendly park access is fundamental to building an elderly-friendly city. However, previous studies have lacked comprehensive analyses that integrate the distribution of the elderly population, park accessibility, park quality, environmental characteristics, and social equity within a unified framework. Specifically, the supply–demand imbalance mechanism underlying the spatial variations in accessibility has not been adequately addressed. This study employs an improved two-step floating catchment area (2SFCA) method, combined with Lorenz curves and urban park-adapted Gini coefficients, to examine the supply–demand relationship and allocation differences between the elderly population and parks at the neighborhood and community levels. The analysis highlights issues related to equity and accessibility and explores their spatial disparity and influencing factors. The key findings are as follows: (1) The classic 2SFCA model exhibits significant biases in evaluating park supply–demand relationships, accessibility, and equity at a fine-grained scale, indicating the necessity of high-precision modeling. (2) Park accessibility in the Old City of Nanjing follows a dual-ring pattern of high accessibility, contrasted with clustered areas of low accessibility, while accessibility equity shows a central–peripheral gradient. Overall equity is relatively low, with good walking accessibility within only about one-third of communities. (3) Park supply levels, neighborhood construction year, and plot ratios are the primary factors influencing park accessibility for elderly residents. The comprehensive aging index is positively correlated with the equity in park layout, whereas housing prices and neighborhood size do not exhibit a simple linear relationship with park accessibility or equity for elderly residents. These findings provide a comprehensive and realistic perspective for understanding elderly park accessibility and equity, offering decision-making references for enhancing urban livability, managing an aging society, and formulating spatial equity policies in the future. Full article

The production of essential oils generates substantial quantities of solid post-distillation residues, a largely unutilized waste stream rich in bioactive compounds (e.g., phenolics, flavonoids) as well as polysaccharides. Managing this organic waste presents both environmental and economic challenges. This review critically examines environmentally friendly green innovations and resource-efficient technologies within circular bio-economy strategies for valorizing these residues, focusing on four primary conversion pathways: physico-mechanical, thermochemical, biological, and chemical methods. We highlight their potential for practical applications, including the extraction of active compounds for food, cosmetic, and pharmaceutical industries, utilization in agriculture, incorporation into construction materials and wastewater treatment. Despite these opportunities, wider industrial adoption remains limited by high processing costs and the lack of scalable, cost-effective technologies. Key research gaps included the need for methods applicable at the farm level, optimization of the residue-specific conversion process, and life-cycle assessments to evaluate environmental and economic impacts. Addressing these gaps is crucial to fully exploit the economic and ecological potential of post-distillation solid residues and integrate them into sustainable circular bio-economy practices through various processes. Full article

Slugs are significant agricultural pests and act as vectors for zoonotic parasites. However, current molluscicide options are limited and associated with substantial environmental risks. This study investigates the role of aldehyde dehydrogenase (ALDH) in the biosynthesis of farnesoic acid (FA), a key intermediate in the sesquiterpenoid hormone pathway, in two slug species: Philomycus bilineatus and Laevicaulis alte. Transcriptomic analysis revealed that both species possess conserved sesquiterpenoid biosynthetic pathways, yet they exhibit distinct levels of ALDH gene expression and differences in FA content. RNA interference (RNAi)-mediated gene silencing was employed to validate the potential of these candidate genes as targets for molluscicide development. Structural modeling of ALDH proteins using AlphaFold2 demonstrated notable divergence in the architecture of their active sites, suggesting species-specific enzymatic properties. Citral, a known inhibitor of ALDH, significantly reduced FA production in vivo and exhibited contact toxicity against both slug species. The lethal concentration 50 (LC₅₀) values were determined to be 378.2 g/L for P. bilineatus and 85.2 g/L for L. alte, respectively. Molecular docking analyses indicated that citral binds within the conserved substrate-binding tunnel of ALDH, potentially inhibiting the oxidation of farnesal. These findings establish ALDH as a critical enzymatic target for disrupting endogenous hormone biosynthesis in slugs and support the development of novel, eco-friendly molluscicides targeting the sesquiterpenoid pathway. Full article

Background/Objectives: Caffeic acid is a hydroxycinnamic acid that has a wide range of applications in the medical field. The synthesis of caffeic acid using microbial fermentation technology is an environmentally friendly method. Methods: By engaging various enzymes, specifically 4-hydroxyphenylacetate 3-monooxygenase (HpaB), sourced from diverse bacterial strains, we successfully engineered a functional version of this enzyme within Escherichia coli, enabling the production of caffeic acid. In addition to the two common tyrosine ammonia lyases (TAL) and HpaC, different combinations of HpaB demonstrated varying abilities in converting the substrate L-tyrosine into the desired product, caffeic acid. Results: Under shake-flask culture conditions, the highest yield of caffeic acid was achieved with an enzyme mixture containing HpaB from Escherichia coli, reaching 75.88 mg/L. Enhancing the activity of the rate-limiting enzyme through engineering could potentially increase caffeic acid titer. This study aims to conduct a semi-rational design of HpaB through structure-based approaches to screen for mutants that can enhance the production of caffeic acid. Initially, the predicted three-dimensional structure of HpaB was generated using AlphaFold2, and subsequent analysis was conducted to pinpoint the critical mutation sites within the substrate-binding pocket. Five key amino acid residues (R113, Y117, H155, S210 and Y461) located in the vicinity of the flavin adenine dinucleotide binding domain in HpaB from Escherichia coli could be instrumental in modulating enzyme activity. Subsequently, the mutant S210G/Y117A was obtained by iterative saturation mutagenesis, which increased the titer of caffeic acid by 1.68-fold. The caffeic acid titer was further improved to 2335.48 mg/L in a 5 L fermenter. The findings show that the yield of caffeic acid was significantly enhanced through the integration of semi-rational design and fermentation process optimization. Full article

The rapid growth of online food delivery in urban areas reflects changing consumer lifestyles, but it has also contributed to increasing plastic waste and challenges in waste management. This study investigated the composition of municipal solid waste (MSW) related to online food delivery, consumer ordering behavior, and single-use plastic (SUP) generation in households in the Bangkok Metropolitan Area. Data were collected from 385 food delivery customers via online questionnaires. The results show that the proportion of plastic waste in MSW has increased, with 76.6% of participants reporting higher online food delivery usage. SUPs from food delivery, including non-essential items such as plastic films, spoons, and cutlery, were prevalent, and participants rarely selected green options to opt out of receiving them. These findings highlight the need for targeted interventions, including closed-loop management involving producers, platforms, consumers, and government. Policy recommendations include implementing extended producer responsibility (EPR) for environmentally friendly packaging, providing incentives for merchants and consumers to reduce SUP, applying the polluter-pays principle (PPP) to users, and designing government policies to regulate SUP and improve plastic waste management. Full article

Highly accurate quantitative detection of heavy metals is crucial for preventing environmental pollution and safeguarding public health. To address the demand for sensitive and specific detection of Cu²⁺ ions, we have developed carbon dots using a simple hydrothermal process. The synthesized carbon dots are highly stable in aqueous media, environmentally friendly, and exhibit strong blue photoluminescence at 440 nm when excited at 352 nm, with a quantum yield of 5.73%. Additionally, the size distribution of the carbon dots ranges from 2.0 to 20 nm, and they feature excitation-dependent emission. They retain consistent optical properties across a wide pH range and under high ionic strength. The photoluminescent probes are selectively quenched by Cu²⁺ ions, with no interference observed from other metal cations such as Ag⁺, Ca²⁺, Cr³⁺, Fe²⁺, Fe³⁺, Hg²⁺, K⁺, Mg²⁺, Sn²⁺, Pb²⁺, Sr²⁺, and Zn²⁺. The emission of carbon dots exhibits a strong linear correlation with Cu²⁺ concentration in the range of 0–14 μM via a static quenching mechanism, with a detection limit (LOD) of 4.77 μM in water. The proposed carbon dot sensor is low cost and has been successfully tested for detecting Cu²⁺ ions in general water samples collected from rivers in Taiwan. Full article

Gas-insulated switchgear (GIS) offers multiple advantages compared to air-insulated switchgear (AIS); primarily, due to its more compact design and reduced maintenance requirements. In recent years, environmentally friendly replacement gases for SF₆ have become an important research topic, not least because EU regulation will ban the use of SF₆ in new equipment for its member states in the coming years. For detecting defects inside equipment, partial discharge (PD) measurements are an important and well-established method, including in acceptance tests (FAT and SAT) and online monitoring. An important question is whether the PD behavior of various defects analyzed in SF₆ differs in potential replacement gases. In this work, standard geometries in form of needle plane arrangements were used to analyze the PD inception behavior of natural origin gases (synthetic air, CO₂ and N_2,) in comparison to SF₆ at various application relevant pressures. PD was measured both by the conventional (IEC 60270 conform) and UHF technique, recording the phase resolved partial discharge patterns (PRPDs), as well as emitted UHF-pulses. The tip radius and the protrusion length of the needle electrode were varied in order to investigate the influence of the electric field distribution on the PD inception behavior. Results show positive pressure dependence, but also deviations from the linear growth of PDIV, intermittent discharge behavior in synthetic air for some conditions and high-current discharges in the N₂ in the setup used. Full article

In this study, ZnO–GO nanocomposites were synthesized from waste Zn–C batteries and used for the photocatalytic degradation of malachite green (MG) under UV light. ZnO–GO nanocomposites with different GO contents (1, 2.5, and 5 wt%) were prepared at room temperature and characterized by XRD, SEM, EDS, and UV–Vis spectroscopy. The GO content significantly affects the morphology, optical properties, and photocatalytic activity of the nanocomposites. In the presence of ZnO NPs, a malachite green degradation efficiency of 96.25% was achieved in 90 min, while ZnO–1%GO, ZnO–2.5%GO, and ZnO–5%GO achieved 95.35%, 97.27%, and 99.6% MG degradation, respectively, in just 30 min. The photocatalytic degradation process of MG was optimized using Response Surface Methodology (RSM). The effects of GO content, catalyst dosage, initial MG concentration, and irradiation time on the efficiency of photocatalytic degradation were investigated, and optimal conditions were determined. Under optimal conditions, a photocatalytic degradation efficiency of 98.51% was achieved. These results indicate that ZnO–GO nanocomposites synthesized from waste Zn–C batteries are efficient and environmentally friendly photocatalysts for the treatment of dye-contaminated wastewater. Full article

Bacterial biosurfactants have potential applications in green cleaning due to their environmental friendliness. Among all isolated bacterial strains in this study, strain N33 exhibited the most potent oil-displacing activity and was identified as Pseudomonas aeruginosa. Its biosurfactant yield was approximately 550 mg/L, and structural characterization revealed it to be a glycolipid-type biosurfactant. The oil-displacing ring diameters of the biosurfactant against vegetable oil, paraffin oil, and crude oil reached 6.3 ± 0.3 cm, 5.8 ± 0.2 cm, and 3.8 ± 0.5 cm, respectively. Its critical micelle concentration (CMC) was determined to be 150 mg/L, with a corresponding surface tension of 39.55 mN/m. Notably, this bacterial biosurfactant significantly improved interfacial wettability, reducing the contact angles of vegetable oil, paraffin oil, and crude oil on oil-wetted glass slides from 93.0°, 99.0°, and 98.8° to 10.0°, 15.0°, and 19.0°, respectively. The emulsification efficiency for the three oils was 80%, 57%, and 10%, respectively. Furthermore, capillary oil removal assays verified that the biosurfactant could efficiently strip oil films from the inner walls of capillaries. These findings demonstrate that the biosurfactant produced by P. aeruginosa strain N33 possesses considerable oil-removal efficacy, thereby providing a novel candidate for the research, development, and application of green detergents. Full article

In medium-sized cities, daily travel often follows routine patterns, which may lead to suboptimal route choices. This study examines such trips and evaluates them to assess the influence of travel information. The research is motivated by the growing importance of sustainable urban mobility and the need to address traffic congestion, environmental concerns, and inefficient transportation choices in the city of Volos, Greece. To achieve that, a survey of two phases was performed. First, self-reported and GPS data of an examined group of 96 participants from the University of Thessaly, Volos, Greece, were collected. The data were used to evaluate the daily trips in terms of travel time, cost, and environmental friendliness. Second, a stated preference survey was designed, targeting motorized vehicle users of the examined group. The survey investigated the extent to which shared information on social media can be used to recommend a different route than the usual one or convince them to shift to a sustainable way of transportation. The analysis shows that travelers are more inclined to accept the recommended route after receiving travel information; however, this effect does not translate into choosing a sustainable mode of transport. We also found that women are more likely to change routes than men. Full article