Environmental Science and Pollution Research最新文献

The sugar industry generates a large amount of sugarcane bagasse residues, which are used for power generation, thus seeking energy balance. During this process, fly ash is generated, which in many cases is disposed of in sanitary landfills and/or open-air dumps. Nevertheless, their incorporation into processes in order to contribute to the circular economy is a current challenge. Accordingly, the main objective of this work was to evaluate alternatives for these ashes in two different sectors, as are construction and environmental fields. Thus, two options have been considered in this study, as are (1) replacement of cement with this waste in the manufacture of mortars and (2) use as an adsorbent in the removal of emerging compounds, such as amoxicillin. The ashes were characterized by several methods, such as XRD, XRF, BET, and proximate and ultimate analyses. Replacements of up to 60% cement with fly ash in the manufacture of mortars are suitable, as they lead to compressive strengths below that of a type H mortar. In the adsorption tests, a removal of 99% was attained with activated ashes, whereas a removal of 96% was attained with the non-activated ones. Based on these results, sugar industry can promote circular economy processes thanks to the advantages of this type of material.

A comparison was made between homogeneous and heterogeneous advanced oxidative processes using TiO₂ supported on non-woven fabric (NWF) in the degradation of the pharmaceutical meloxicam, using a LED radiation. Degradation tests were performed using homogeneous photoperoxidation, Fenton, and photo-Fenton processes. The photo-Fenton process promoted the greatest degradation. The conditions that led to the best results were then used to perform a kinetic study. After 300 min, the system stabilized, reaching 95% degradation. The experimental data followed a pseudo-first order kinetic law. The photocatalyst characterization results indicated a good reproducibility of the superposition method, indicating that the support process was efficient. Among the heterogeneous processes evaluated, the TiO_2sup/LED process was selected, since the photocatalyst results did not show significant differences between the degradations achieved. In the kinetic study, the system was stabilized after 180 min, with a degradation of 94%. The experimental data also obeyed pseudo-first order kinetic law. When comparing the two processes, the degradation was similar, although photocatalysis was able to minimize the toxicity of the solution and reduce the chemical oxygen demand by 78% while the photo-Fenton only reduced 48%. Moreover, photocatalysis required 32% less energy than the photo-Fenton process under the same conditions. The photocatalysis with TiO_2sup and LED radiation, therefore, proved to be effective for the degradation of meloxicam.

In this work, 1, 2 and 3 wt % Ag were deposited on SBA-15 by the impregnation method to investigate the UV-assisted photocatalytic degradation of methyl orange (MO) and methylene blue (MB). The catalysts were characterized by atomic absorption spectroscopy (AAS), nitrogen physisorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV‒Vis diffuse reflectance spectroscopy. The XRD peaks at 38.7, 44.7, 65.0, 77.8 and 82.0° were identified as Ag⁰, which was confirmed via XPS. Decreasing bandgap energy values of 5.3, 3.5, 2.40 and 2.17 eV were observed with increasing Ag wt % for SBA-15, 1Ag/SBA-15, 2Ag/SBA-15, and 3Ag/SBA-15, respectively. The best photocatalytic degradation was obtained with 2Ag/SBA-15, achieving 100% degradation for MO and MB in 30 and 45 min, respectively. Consequently, the higher dispersion of Ag-NPs observed in the TEM micrographs could be explained. Ag⁰ acted as both an electron trap and a plasmonic sensitizer, which suppressed electron‒hole recombination. Pseudo-first-order kinetics were observed in the photocatalytic process for all four catalysts evaluated, reaching the highest constants for the 2Ag/SBA-15 catalyst, with values of 0.1458 and 0.1872 min^-1 for MB and MO, respectively. Hydroxyl radicals (•OH) are crucial for the degradation of both dyes, and the 2Ag/SBA-15 catalyst was still stable after five cycles.

Thermal energy storage systems have gained increasing attention in recent years as effective solutions for improving energy efficiency and promoting sustainability. In this study, an eco-friendly phase change material (PCM) composite was developed by upcycling spent coffee grounds (SCG) into a value-added thermal energy storage material. SCG were employed as a natural supporting matrix, while a eutectic mixture of lauric acid (LA) and stearic acid (SA) with a mass ratio of 70:30 served as latent heat storage component. The composite was prepared by using a vacuum impregnation method. To determine the optimal PCM loading, the LA-SA content was varied between 10 and 70 wt%, and a maximum stable loading of 30 wt% was identified based on leakage performance. The leakage behavior, morphological structure, chemical composition, and thermal properties of composites were systematically investigated by leakage tests, FTIR, XRD, DTA/TG, and DSC analyses. 5%CuO@e-PCMC coded composite showed an effective heat storage efficiency (E), relative thermal storage efficiency (μ), and enthalpy efficiency (λ) as 9%, 80%, and 0.1, respectively. Thermal analysis tests confirmed that the composite structure remained stable without significant degradation over repeated phase change cycles. The results demonstrated that the developed SCG-based PCM composite was a cost-effective and an environmentally friendly candidate for low-temperature thermal energy storage applications, particularly in 33-36 °C range, making it well suited for textile and thermal comfort applications. The ability of SCG to stably accommodate up to 30 wt% of the LA-SA eutectic mixture highlighted their potential as a sustainable and natural alternative supporting material for thermal energy storage and thermal management systems.

Hydrological drought, a persistent challenge in Iran, profoundly impacts water resources, particularly river discharge patterns critical for effective management. This study aims to quantify how hydrological drought shapes the chaotic, multiscale, and predictable dynamics of Atrak River discharge from 1978 to 2018, using an integrated approach of chaos theory, multifractal analysis, and cross-correlation techniques. Daily discharge data and monthly drought indices were used, with monthly data applied for dynamic analysis. Cross-correlation revealed drought intensifies sensitivity to initial conditions and randomness, with delayed effects (lag = 2 months for Lyapunov Exponent [LE]-SDI; lag = -3 for Approximate Entropy [ApEn]-SDI). Sensitivity analysis showed outlier removal shifts CC lags and directions, reduces LE by 74.5% on average, and narrows multifractal spectra (Δα smaller, left-truncation delayed to 41 years), confirming cleaner detection of intrinsic chaos. Autocorrelation-adjusted CC (prewhitening) yielded non-significant p-values (> 0.05) at all lags, indicating apparent delays partly reflect serial dependence. Bootstrap resampling (B = 1000) showed high LE uncertainty in short (31-point) segments, decreasing with longer series, and more chaotic months post-outlier removal. Sample Entropy validated ApEn, confirming moderate-to-low irregularity and seasonal predictability (lowest in June, highest in January). Multifractal spectra revealed a 41-year flood cycle and 25-year drought cycle. These findings improve drought and discharge forecasting models, enabling precise water allocation and reservoir management strategies to mitigate drought impacts in Iran.

The remediation of nanoscale particulate matter generated during restaurant cooking processes presents a unique challenge, characterized by higher flow rates than most engines but at significantly lower pollutant concentrations. As such, it combines the worst aspects of both scenarios. We present a novel solution to this persistent challenge using transient plasma generated by high-voltage (20 kV) nanosecond pulse discharge. This approach has recently demonstrated potential for enhancing electrostatic precipitation (ESP) in capturing oil-based aerosol particles from restaurant emissions and diesel particulates.(Jang, Yoo et al. 2023) However, prior studies have been limited to small-scale systems operating at low flow rates (~ 2.8 CFM, i.e., 0.0013 m³/s). Here, we report particulate matter (PM) mass concentrations plotted over 7-min cooking cycles with 24 hamburgers at 1000X higher flow rates than those reported previously. At flow rates of 2000 and 3000 cubic feet per minute (CFM), i.e., 0.94 m³/s and 1.416 m³/s, we achieve 93.7% and 86.9% reduction in PM, respectively. This system uses a total of 805 Watts of electrical power, which is less than 5% of a typical rooftop blower power (i.e., 18 kW). This system provides the additional benefit of reducing odor. The PE-ESP enables the system to operate at significantly higher flow rates (3000 CFM, i.e., 1.416 m³/s) than current filter-based technologies without creating a large backpressure on the fan (i.e., blower). In fact, our system produces a pressure drop of just 0.85 inches of water gauge (inwg) (212 Pa) at 2000 CFM (0.94 m³/s) and 1.91 inwg (476 Pa) at 3000 CFM (1.416 m³/s), which is considerably lower than current filter-based technologies and well below the blower limit, which can only tolerate a pressure drop of up to 10 inwg (2494 Pa) and represents a relatively firm design constraint. This plasma-enhanced approach demonstrates the potential for deploying such a system to restaurants to improve the efficacy of the remediation of smoke.

Malachite Green (MG), a widely used textile dye, is a toxic and non-biodegradable product commonly found in industrial wastewater. In this work, Fe₃O₄/g-C₃N₄ nanocomposites showed as an eco-friendly photocatalyst, effectively degrading the persistent pollutant to support sustainable wastewater treatment. Fe₃O₄ nanoparticles (NPs) were synthesized using a green route with Camellia sinensis (green tea) leaf extract method and integrated with g-C₃N₄, to form a hetero-structured photocatalyst. X-ray diffraction (XRD) analysis confirmed the successful formation of Fe₃O₄ and the preserved structural integrity of g-C₃N₄ structure. UV-visible diffuse reflectance spectroscopy (UV-vis DRS) revealed that Fe₃O₄ and g-C₃N₄ nanocomposites exhibit enhanced visible-light absorption. Photoluminescence (PL) spectra indicated suppressed recombination of photogenerated charge carriers, implying improved charge separation. Field emission scanning electron microscopy (FESEM) revealed a crumpled, sheet-like morphology. Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analysis confirmed the mesoporous nature of the nanocomposites. Photocatalytic tests under visible light irradiation demonstrated a remarkable degradation efficiency of 99.20% for MG dye at pH 11, significantly outperforming the individual components. Liquid Chromatography-Mass Spectrometry (LC-MS) confirmed the presence of intermediate products, supporting a stepwise degradation mechanism of MG dye through demethylation and oxidative reactions.

This study investigates the immobilization of cesium and barium contaminants in borate waste solutions using clinoptilolite-bearing and mordenite-bearing additives within cement matrices, with a focus on their adsorption capacity. These zeolites were incorporated at varying ratios into blends of Portland cement (PC) and calcium sulfoaluminate cement (CSAC). A batch adsorption experiment was conducted, utilizing borate waste solutions containing trace concentrations of simulated cesium-137 radioisotopes and its metastable decay product barium-137, to evaluate their effectiveness in reducing the leachability of these contaminants after a 28-day solidification period. The experimental setup included a comprehensive analysis involving ASTM standard leaching tests over 11 days, alongside compressive strength testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD) for morphological and chemical assessment at the cement mineral level. Inductively coupled plasma optical emission spectroscopy (ICP-OES) and mass spectroscopy (ICP-MS) analyses were conducted on the leachate from the solidified cement pastes to study the physical and chemical changes of the cement pastes matrices. Results showed that cement paste matrices with untreated clinoptilolite-bearing samples exhibited the highest cesium adsorption capacity in the boric acid liquid waste, whereas KCuHFC-treated zeolite-bearing (i.e., clinoptilolite-bearing and mordenite-bearing) samples showed diminished capacity for cesium adsorption from the boric acid liquid waste. The use of 5% clinoptilolite in the PC/CSAC blend produced optimal physical and chemical stability, highlighting its potential for effective cesium immobilization in waste management.

Developing countries with a high growth of young population are often faced with the burden of a housing deficit. Manufacture and utilization of locally abundant natural materials in building services remain the most viable option in mitigating such challenges. However, environmental safety and public health concerns due to toxic pollutants in such construction materials should be given priority attention. The need to develop local sustainable construction materials that meet the United Nations' 2030 target for Sustainable Development Goals (SDGs) necessitated this study. Agbani has large deposits of quality clay minerals that have been studied. The authors blended and reinforced Agbani clay with granite to produce composite clay materials that can be used in building services. The samples were heated to 900 °C, 1000 °C, 1100 °C, and maximum temperature of 1200 °C. XRF, XRD, physical properties, mechanical behaviour, and physicochemical properties of the samples were characterized using different combined experimental techniques. The result of the XRF analysis shows that SiO₂, Al₂O₃, and Fe₂O₃ constitute the major oxides while the XRD analysis shows that quartz, orthoclase, kaolinite, and albite dominate the mineralogical composition of the clay. The results of the physical properties of the Agbani clay deposit suggest remarkable improvement in the physical properties such as apparent porosity, bulk density, and water absorption with the addition of granite and firing at 1200 °C. Mechanical property results show that impact strength, impact energy, modulus of rupture, and compressive strength all increased with the addition of granite and firing to elevated temperature. However, the plasticity limit was adversely affected as it reduced. For all the clay samples produced, blending them with granite and firing at 1200 °C led to a significant reduction in the toxic materials such as lead, mercury, arsenic, phosphorous, and chloride.

Leaf-based leather is a biodegradable, negative carbon emissions, and economically suitable material compared to the conventional leather-making process. In this research, jute leaf (30 gm), cellulose (2 gm), and natural rubber latex (10 ml) composition combined composite exhibited superior tensile strength (9.58 MPa). Fourier transform infrared spectroscopy (FTIR) showed that formed aryl groups in this composite material indicated jute leaves crosslink with natural rubber latex and cellulose. Scanning electron microscopy (SEM) also represents porosity and reduced fiber pull-out. However, when thermoplastic polyurethane (TPU) was heat-compressed with this composite material, it enhanced tensile strength properties (28.9 MPa) and elongation (15.3%). Due to TPU crosslinking, FTIR confirms aryl signatures and urethane linkages formed by hydroxyl-NCO reactions, enhancing chain interactions and mechanical integrity, and SEM shows a porous microstructure supporting cohesion and interfacial adhesion. Contact-angle measurements (~ 85°) indicate the same hydrophobicity, comparable to animal leather (~ 90°). The jute leaf composite degraded within 4 months in the soil, whereas the TPU-compressed variant biodegraded within 6 months. This work presents a sustainable jute leaf bio-composite to replace leather in products such as backpacks, wallets, bags, book and file covers, automotive or home décor, creating bioeconomic opportunities in Bangladesh.