Search Results (44)

The increasing adoption of additive manufacturing in the construction sector has intensified the demand for lightweight, recyclable cement-based composites with low environmental impact, suitable for automated 3D printing. Foamed concrete reinforced with dispersed fibers and incorporating recycled constituents represents a promising class of multifunctional materials. However, its environmental performance remains insufficiently characterized. This study provides a comprehensive evaluation of thermal stability, leaching behavior, and microbial resistance of 3D-printable fiber-reinforced foamed cement composites produced with recycled components. Thermogravimetric–Fourier transform infrared (TG–FTIR) analysis confirmed a characteristic three-stage thermal decomposition pathway typical of hydrated cementitious systems. All composites exhibited high thermal stability, with residual masses of 88.56–90.17% at 900 °C. The binder type exerted a stronger influence on decomposition behavior than atmospheric exposure or freeze–thaw conditioning. Leaching tests revealed strongly alkaline eluates (pH 11.0–11.4), low total organic carbon (<0.6 wt.%), and only trace concentrations of BTEX (35–41 μg/kg), PAHs, and PCBs. Alkali activation increased the release of chromium (3.6–4.0 mg/kg), arsenic (1.2 mg/kg), copper (4.5 mg/kg), antimony (0.26 mg/kg), and sulfates (2700–4700 mg/kg), accompanied by elevated total dissolved solids (~18,000 mg/kg). Nevertheless, all environmentally relevant constituents remained well below the waste acceptance criteria (WAC), confirming effective immobilization of hazardous species within the hardened matrix. The results provide new insights into the relationships among material composition, porous microstructure, and environmental safety, demonstrating that the developed 3D-printable foamed composites exhibit robust performance, suitability for safe and durable applications, and favorable environmental performance. Full article

Contamination of water bodies by emulsified gasoline hydrocarbons, particularly BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), represents a critical environmental challenge due to their toxicity and resistance to conventional treatment methods. In this study, carbonized biosorbents derived from rice husk (CRH) and walnut shell (CWS) were developed for efficient removal of emulsified gasoline from water. The materials were prepared via carbonization under CO₂ atmosphere (300–800 °C), enabling simultaneous carbonization and activation. Structural and surface properties were characterized using Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray fluorescence spectroscopy (XRF). The results demonstrated a strong dependence of adsorption performance on carbonization temperature, with maximum removal efficiencies of 90.2% (CRH-600) and 96.5% (CWS-700). The superior performance of CWS-700 was associated with its highly developed hierarchical pore structure (up to 670 m² g⁻¹), increased carbon content, and enhanced hydrophobicity. Kinetic studies revealed pseudo-second-order behavior, with equilibrium achieved within 25–30 min at near-neutral pH. Gas chromatographic analysis confirmed the complete removal of BTEX and light hydrocarbons (C1–C9) using CWS-700, highlighting its high selectivity toward aromatic compounds. The adsorption mechanism was attributed to the synergistic effect of micropore filling, hydrophobic interactions, and π-π interactions with aromatic hydrocarbons. The obtained results demonstrate that biomass-derived carbon materials, particularly walnut shell-based sorbents, are promising low-cost candidates for the treatment of complex water systems contaminated with emulsified petroleum hydrocarbons. Full article

Methane generation from anaerobic biodegradation of fugitive diluent hydrocarbons is an important source of greenhouse gas emissions from oil-sands tailings, yet predictive tools that preserve hydrocarbon-level information remain limited. This study develops a hydrocarbon-resolved methane-prediction model and tests it on a case study involving a twelve-component diluent mixture containing BTEX, normal alkanes, and iso-alkanes. The model integrates stoichiometric methane yields, compound-specific lag times, Monod-type hydrocarbon consumption, logistic activation, and a single methane-conversion factor to simulate cumulative methane production and group-level methane contributions through time. Model performance is evaluated against measured methane and residual hydrocarbon data using normalized mean square error. The model reproduces cumulative methane with improved normalized mean square error relative to the existing stoichiometric benchmarks, while group-resolved outputs and robustness analyses show that predictive performance is governed primarily by conversion efficiency and lag structure. On the other hand, inclusion of an unresolved biodegradable-substrate fraction did not strengthen model agreement. These results indicate that the modeled hydrocarbon set captures the principal methane-generating substrate pool and that the proposed framework provides an accurate and mechanistically interpretable basis for methane prediction in oil-sands tailings. Full article

This study evaluates the feasibility of continuous indoor pollutant monitoring as an indirect method for assessing extended ventilation performance in residential buildings. This research addresses key limitations of conventional short-term tracer-gas methods, which cannot account for occupant lifestyle, environmental fluctuations, and extended ventilation variability. The study employs a diffusion-based framework to interpret pollutant-concentration equalization across the residential space over extended monitoring periods. We conducted field experiments in an apartment unit equipped with both ducted and non-ducted ventilation systems. Pollutants (PM_2.5, CO₂, HCHO, and aromatic VOCs (BTEX + styrene)) were uniformly emitted. PM_2.5 and CO₂ were continuously monitored at six spatially distributed points using calibrated sensors, while HCHO and aromatic VOCs were quantified by repeated active sampling and laboratory analysis. Under ducted ventilation, average pollutant reduction rates reached 86.8% for PM_2.5, 58.3% for CO₂, and 53.6% for HCHO. Simultaneously, spatial concentration variance decreased by up to 71% within 120 min, indicating strong diffusion-driven equalizations. These results support the feasibility of extended ventilation performance monitoring using continuous pollutant sensing, with implications for IAQ management, energy optimization, and future integration with data-driven predictive models. Full article

Volatile aromatic compounds (BTEX: benzene, toluene, ethylbenzene, and xylenes) are toxic and odor-active volatile organic compounds of environmental and health concern. Conventional biofiltration systems often rely on organic packing materials that deteriorate over time, motivating the evaluation of more durable inorganic alternatives. In this study, andesite, a volcanic rock, was assessed as a packing material in a laboratory-scale biotrickling filter (BTF) for the removal of BTEX from air streams. The reactor was operated under controlled conditions at different empty-bed residence times, and BTEX concentrations were monitored using TD-GC/MS. Removal performance was interpreted in relation to biofilm development, supported by physicochemical characterization of the packing material and contextual microbial analysis of the microbial community structure by amplicon sequencing. The results showed that the andesite-packed BTF achieved high BTEX removal efficiencies after an acclimation period, with stable operation under the tested conditions. Microbial analysis revealed the dominance of bacterial groups commonly associated with aerobic degradation of aromatic hydrocarbons. These findings indicate that andesite can function as a mechanically stable and biologically compatible inorganic support for BTEX treatment in biotrickling filters at the laboratory scale. The study is limited to bench-scale operation and community-level microbial analysis; therefore, further work is required to evaluate long-term performance, scale-up potential, and functional metabolic interactions. Full article

Using the Ministry of Environment’s fixed-site air quality monitoring network, we analyzed multiple hazardous air pollutants (HAPs)—including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals—during 2021–2024 and compared their concentrations with internationally reported levels. Pronounced spatial heterogeneity was observed across stations, particularly for VOCs and heavy metals. Stations A, E, and F were dominated by alkanes, whereas stations B, C, and D exhibited higher proportions of oxygenated VOCs (mainly aldehydes and ketones). Across the network, formaldehyde (0.015 μg/m³), dichloromethane (2.60 μg/m³), toluene (2.53 μg/m³), and acetaldehyde (0.004 μg/m³) were identified as the most abundant species. Stations A and E served as VOC hotspots—formaldehyde peaked at station A and toluene at station E—likely due to nearby industrial and port activities. Concentrations of BTEX generally decreased throughout the study period, with a minor rebound at station C in 2022. Regarding heavy metals, elevated concentrations of lead (16.83 ng/m³), nickel (4.71 ng/m³), and arsenic (1.29 ng/m³) were observed at station A, again suggesting influences from industrial or port-related emissions. Overall, formaldehyde, benzene, and 1,2-dichloroethane were identified as key pollutants of concern, with station A representing the most critical hotspot in the monitoring network. Full article

BTEX compounds (benzene, toluene, ethylbenzene, and xylene isomers) are aromatic hydrocarbons widely used in various industries. Due to their volatility, they become persistent pollutants in workplace air, posing serious risks to worker health. The aim of this study is to systematically map academic publications on BTEX exposure and health effects and to evaluate the impact of exposure levels in industrial settings on worker health. Publications obtained from the Web of Science database between 2010 and 2025 were bibliometrically analyzed in terms of productivity, collaboration networks, thematic trends, and analysis methods. In addition, the sources of BTEX compound dispersion, analysis methods, and industrial hazard classifications were evaluated through content analysis. According to the findings, Iran and China stood out as the most active countries, with publication intensity peaking in 2023. BTEX exposure was observed to be particularly high in the petrochemical sector. However, there is a lack of studies that systematically address the direct effects on worker health. This study aims to contribute to the more effective management of BTEX-related exposure risks by providing decision-makers with scientifically based and interpretable analyses. Full article

This study investigates the atmospheric concentrations, spatiotemporal distribution, the associated health risks and the ozone formation potential of benzene, toluene, ethylbenzene and xylenes (BTEX) across 33 monitoring sites of Greece over a one-year period. Samples were collected using passive diffusive samplers and analyzed by gas chromatography–mass spectrometry (GC-MS). The highest BTEX concentrations were detected during winter and autumn, particularly in urban and industrial areas such as in the Attica and Thessaloniki regions, likely due to enhanced emissions from combustion-related activities and reduced atmospheric dispersion. Health risk assessment revealed that hazard quotient (HQ) values for all compounds were within the acceptable limits. However, lifetime cancer risk (LTCR) for benzene exceeded the recommended limits in multiple regions during the colder seasons, indicating notable public health concern. Source apportionment using diagnostic ratios suggested varying seasonal emission sources, with vehicular emissions prevailing in winter and marine or industrial emissions in summer. Xylenes and toluene exhibited the highest ozone formation potential (OFP), underscoring their role in secondary pollutant formation. These findings demonstrate the need for seasonally adaptive air quality strategies, especially in Mediterranean urban and semi-urban environments. Full article

This study aimed to investigate the concentrations of BTEX (benzene, toluene, ethylbenzene, ortho-xylene (o-), and meta and para-xylene (m-,p-)) in Croatian households between December 2023 and January 2025. The results showed that BTEX concentrations were higher indoors than outdoors, suggesting a considerable contribution from indoor sources. Significant statistical differences were found between indoor and outdoor levels of ethylbenzene, m-,p-xylene, and o-xylene, especially during cold periods when indoor activities increase and ventilation decreases. Spearman’s correlation analysis showed weak correlations between benzene and other BTEX compounds, implying multiple distinct sources such as cooking, smoking, and outdoor air infiltration. Full article

The aim of this work was the preparation of ceramic monolithic catalysts for the catalytic oxidation of gaseous mixture of benzene, toluene, ethylbenzene and o-xylene BTEX. The possibility of using zirconium dioxide (ZrO₂) as a filament for the fabrication of 3D-printed ceramic monolithic carriers was investigated using fused filament fabrication. A mixed manganese and iron oxide, MnFeO_x, was used as the catalytically active layer, which was applied to the monolithic substrate by wet impregnation. The approximate geometric surface area of the obtained carrier was determined to be 53.4 cm², while the mass of the applied catalytically active layer was 50.3 mg. The activity of the prepared monolithic catalysts for the oxidation of BTEX was tested at different temperatures and space times. The results obtained were compared with those obtained with commercial monolithic catalysts made of ceramic cordierite with different channel dimensions, and with monolithic catalysts prepared by stereolithography. In the last part of the work, a kinetic analysis and the modeling of the monolithic reactor were carried out, comparing the experimental results with the theoretical results obtained with the 1D pseudo-homogeneous and 1D heterogeneous models. Although both models could describe the investigated experimental system very well, the 1D heterogeneous model is preferable, as it takes into account the heterogeneity of the reaction system and therefore provides a more realistic description. Full article

Background/Objectives: Degenerative arthritis is a chronic inflammatory disease marked by tissue degradation and vascular fibrosis. Macrophages play a central role in the inflammatory response by releasing mediators such as nitric oxide (NO), interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), and prostaglandin E2 (PGE2). This study aimed to investigate the anti-inflammatory potential of BTEX-K, a formulation of dried red ginseng combined with alpha-galactosidase, in lipopolysaccharide (LPS)-stimulated cells. Methods: LPS-treated immune cells were used to assess the anti-inflammatory effects of BTEX-K. The levels of NO, IL-6, TNF-α, and PGE2 were measured following BTEX-K treatment. The protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was evaluated. Cytotoxicity assays were conducted to determine whether the observed effects were due to cell viability loss. The involvement of MAPK signaling and NF-κB pathway modulation was examined by analyzing JNK phosphorylation, IκB degradation, and PPAR-γ expression. Results: BTEX-K significantly reduced the production of NO, IL-6, TNF-α, and PGE2 in LPS-treated cells without inducing cytotoxicity. The protein expression levels of iNOS and COX-2 were also suppressed. Furthermore, BTEX-K inhibited the LPS-induced phosphorylation of JNK in the MAPK pathway. It restored IκB levels and suppressed NF-κB activation by preventing the downregulation of PPAR-γ. Conclusions: BTEX-K demonstrates notable anti-inflammatory effects by inhibiting key inflammatory mediators and signaling pathways in immune cells. These findings support its therapeutic potential in mitigating inflammation-related symptoms, including pain, swelling, and redness, commonly seen in degenerative arthritis. Full article

Springs located in urban historic areas are important for groundwater management, the protection of green spaces, and the preservation of park functions and urban structure. This article presents the results of a study of selected Warsaw springs in the city center under conservation protection, focusing on their hydrogeological characteristics, hydrogeochemical analysis, and pressures associated with urban development. Field and laboratory analyses, as well as hydrodynamic modeling, made it possible to assess the quantity and quality of water from the springs. Hydrodynamic studies showed that the area of the spring recharge zone of 13.77 ha is characterized by an average time of water exchange of approx. 26 years and a low infiltration recharge, an average of 18 mm/year. Hydrogeochemical analyses showed that spring water has a complex, multi-ion hydrogeochemical type: Cl-SO₄-HCO₃-Ca-Na, Cl-HCO₃-SO₄-Ca-Na, Cl-HCO₃-Na-Ca, and NO₃-Cl-HCO₃-Ca-Na, including the occurrence of hazardous substances such as PAH and BTEX, PCBs, non-ionic detergents, and heavy metals. The results indicate that urbanization significantly affects groundwater levels and spring recharge areas, which can limit the availability of water in green and recreational areas. The results of the study indicate the need for action to increase groundwater resources through managed aquifer recharge for rainwater management in densely built-up areas. In terms of water quality measures, due to the unsatisfactory chemical water status, the use of spring water for irrigation of urban vegetation or its incorporation into the active recreational infrastructure of the park currently appears to be fraught with considerable risk, hence the need to take protective action in the spring recharge zone through the regular monitoring of groundwater quality, the legal designation of protection zones, and the implementation of policies that support urban water retention. It is necessary to implement pre-treatment solutions (aeration, desalination) or introduce appropriately resistant vegetation. Any type of activity that allows the use of water after treatment will certainly contribute to making the park more attractive as a place of recreation and leisure for residents. Findings from the research can support decisions on protecting green spaces and adapting cities to climate change. Full article

Volatile organic compounds (VOCs) contribute to air pollution and pose health risks. This study investigates VOC emissions from petroleum refining and petrochemical industries using passive and active fenceline monitoring techniques. The primary objective of this research is to compare the characteristics and detection performance of passive and active sampling methods for VOC monitoring, particularly focusing on benzene and other major components, such as BTEX. A total of 87 VOC species were analyzed, with benzene, toluene, ethylbenzene, and xylene (BTEX) being dominant. Passive sampling detected benzene at an average concentration of 3.60 µg/m³, whereas active sampling recorded 1.33 µg/m³, showing up to 2.5 times higher values in passive sampling. In certain locations, benzene levels exceeded the EPA action level of 9 µg/m³, with a peak value of 18.37 µg/m³ at one sampling point. Meteorological conditions significantly influenced VOC concentrations, with stronger winds dispersing emissions more widely. This study provides crucial data for VOC emission control and regulatory policy development, emphasizing the need for continuous monitoring and targeted reduction strategies in industrial zones. Full article

This study presented a comprehensive comparison of soil gas sampling methodologies to monitor volatile organic compounds (VOCs) at two industrial sites in northern Italy. Utilizing active sampling techniques, such as stainless-steel canisters, vacuum bottles, and sorbent tubes, alongside passive methods like low-density polyethylene (PE) membranes, sorbent pens, and Waterloo Membrane Samplers (WMS), the research examines their effectiveness under varied environmental conditions. Five field campaigns were conducted in two areas of the industrial sites characterized by BTEX and chlorinated solvent contamination. The results highlighted that active sampling, while expensive, provides real-time, high-resolution VOC concentration data, often outperforming passive methods for heavier compounds (e.g., hexachlorobutadiene). However, using the active systems in certain campaigns, challenges such as high soil humidity or atmospheric air infiltration were observed, resulting in an underestimation of the soil gas concentrations. Passive sampling systems demonstrated cost-effective, efficient alternatives, offering consistent spatial and temporal coverage. These methods showed alignment with active techniques for lighter compounds (e.g., TCE and BTEX) but faced limitations in sorbent saturation and equilibrium time for heavier VOCs (e.g., hexachlorobutadiene), requiring adjustments in exposure duration to enhance accuracy. PE samplers provided results comparable to active methods, especially for BTEX and TCE, while WMS and sorbent pens exhibited lower sensitivity for certain analytes. This underscores the importance of optimizing sampler configurations and deployment strategies. The findings emphasize the value of integrating active and passive approaches to achieve robust VOC assessments in heterogeneous subsurface environments. Full article

Levels of BTEX (Benzene, Toluene, Ethylbenzene and p-Xylene) were determined in the ambient air of two urban sites located in the Metropolitan Area of Monterrey (MAM) during two climatic seasons of 2023. The study revealed that BTEX compounds in Santa Catarina and Obispado had the following relative abundance: p-Xylene (20.09 µg m⁻³) > Toluene (19.50 µg m⁻³) > Ethylbenzene (19.34 µg m⁻³) > Benzene (17.39 µg m⁻³). Their concentrations were consistent with global reports, showing diurnal and seasonal variability. Levels were higher during the dry season due to elevated temperatures, low wind speeds, and lack of precipitation, which reduced pollutant dispersion. BTEX concentrations in Santa Catarina (industrial site) and Obispado (urban site) were influenced by local activities like industrial processes, area sources, and vehicular traffic. Wind rose analysis confirmed the influence of local sources, with higher BTEX levels when winds came from the east. This was linked to pollutant transport within MAM and thermal inversions trapping pollutants during the dry season. Benzene/Toluene (B/T) and p-Xylene/Ethylbenzene (X/E) ratios showed that the sampling sites were influenced by vehicular sources and local fresh emissions. Benzene inhalation has an unacceptable lifetime cancer risk, urging MAM authorities to implement stricter regulations to protect public health. While non-cancer risks were within acceptable limits, controlling Benzene and p-Xylene emissions remains critical to improving air quality. Full article