Environmental Science and Pollution Research最新文献

Simultaneous nitrification and denitrification (SND) of nitrogen-rich wastewater in microbial fuel cells (MFCs) is a new-age technology capable of treating wastewater and concurrently generating bioelectricity. Compared to the conventionally used biological nitrogen elimination processes, SND in MFC is much more energy and cost-efficient because it uses less organic carbon and excludes the nitrified liquid circulation process. In this work with a dual-chambered MFC, carbon-rich synthetic wastewater (CRSW) with an invariable glucose concentration of 2 g/L has been treated in the anodic chamber and nitrogen-rich synthetic wastewater (NRSW) containing 1 g/L, 2 g/L, and 3 g/L ammonium chloride (NH₄Cl) concentration has been treated in the cathodic chamber and concurrently bioelectricity has been generated. Results showed that CCV-2 with 2 g/L NH₄Cl load in closed circuit (CCV) mode generated the highest cell voltage, current density, and volumetric power density of 80.56 mV, 23.69 mA/m², and 12.97 mW/m³. Removal of chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), nitrite, and nitrate was also highest in CCV-2 being 90.25%, 92.18%, 85.78%, and 86.53% respectively. With further increment of NH₄Cl concentration to 3 g/L concentration there was a decrement in COD, TKN, nitrite, nitrate, and power generation output because TKN concentration higher than 3 g/L slowed down the growth of exoelectrogenic bacteria and decreased organic and nitrogen removal rate along with power output. All experiments in CCV mode gave better results than their counterparts operated in open circuit (OCV) mode. In microbial community structure analysis, the dominant genus was found to be Brevendimonas, Sphingomonadaceae, and Achromobacter in the cathodic chamber treating NRSW.

As the demand for electric vehicles increases, effective solutions for recycling end-of-life lithium-ion batteries become crucial. Since lithium iron phosphate (LFP) batteries represent a significant portion of the automotive battery market, this research introduces an innovative method to produce concentrated lithium solutions by combining a calcination process with a microwave-assisted hydrometallurgical process. The initial steps involve safe collection and disassembly of discarded batteries to preserve components and minimize contamination. The cathode coils are separated and ground to a particle size smaller than 0.25 mm, concentrating 96% of the lithium compounds. Afterward, the cathode material undergoes calcination for 1 h at temperatures ranging from 300 to 900 °C in air and N₂ atmospheres. For samples treated in an oxidative atmosphere, the complete phase conversion of LiFePO₄ to Li₂Fe₃(PO₄)₃ occurs at 500 °C, whereas in an inert atmosphere, this phase change fully manifests at 700 °C. Different sulfuric acid concentrations (0.5, 1.0, and 1.5 mol/L) are subsequently used in the microwave-assisted leaching process for all the calcined and non-calcined cathodic powders. Using leaching with aqua regia as a reference for the complete leaching of metals, the best results in terms of lithium selectivity are achieved with samples calcined at 500 °C and leached with 0.5 mol/L sulfuric acid. Under these conditions, 75% of all the lithium and only 2.5% of all the iron are extracted in solution. This result demonstrates that calcination in an air atmosphere prior to a hydrometallurgical process plays a fundamental role in achieving high lithium selectivity without the need for any other additives.

Solar energy is widely acknowledged as a renewable and environmentally friendly energy source. Efficient storage of heat energy is a crucial challenge in solar thermal applications. Phase change materials (PCMs) have gained prominence due to their unique ability to store and release thermal energy through phase transition. The advantageous characteristic of PCMs is their low melting point, facilitating efficient heat storage and retrieval through latent heat of vaporization. This comprehensive review focuses on selecting suitable PCMs for diverse applications, considering their melting point and thermal properties. PCMs with high heat capacity and excellent solar radiation absorption are favored in solar applications, especially for systems requiring large thermal energy storage capacities. This review article underscores the importance of PCMs in low-temperature (0-120 °C) solar thermal applications such as solar desalination, solar water heaters, solar cookers, solar dryers, solar air heaters, and solar chimneys, emphasizing their role in practical heat storage and release. By carefully selecting PCMs based on melting point and thermal properties, the performance and efficiency of solar thermal systems can be optimized, contributing to a greener and more sustainable future.

Air pollution is a significant global challenge with profound impacts on human health and the environment. Elevated concentrations of various air pollutants contribute to numerous premature deaths each year. In Europe, and particularly in Poland, air quality remains a critical concern due to pollutants such as particulate matter (PM), which pose serious risks to public health and ecological systems. Effective control of PM emissions and accurate forecasting of their concentrations are essential for improving air quality and supporting public health interventions. This paper presents four advanced deep learning-based forecasting methods: extended long short-term memory network (xLSTM), Kolmogorov-Arnold network (KAN), temporal convolutional network (TCN), and variational autoencoder (VAE). Using data from eight cities in Poland, we evaluate our methods' ability to predict particulate matter concentrations through extensive experiments, utilizing statistical hypothesis testing and error metrics such as mean absolute error (MAE) and root mean square error (RMSE). Our findings demonstrate that these methods achieve high prediction accuracy, significantly outperforming several state-of-the-art algorithms. The proposed forecasting framework offers practical applications for policymakers and public health officials by enabling timely interventions to decrease pollution impacts and enhance urban air quality management.

The study uses co-solvent-based transesterification to turn chicken dung into biodiesel. Dry rendering was used to create chicken waste from lost fleshing and processing wastes, with a maximum fat percentage estimated to be 10% overall. The rendered chicken dung was then converted to biodiesel by employing potassium hydroxide as a base catalyst, methanol as the primary solvent, and ethanol as a co-solvent. Reaction parameters that were separately adjusted for methanol- and ethanol-based transesterification were used to identify the ideal range for the parameters. Along with production optimization, the biodiesel/waste chicken methyl ethyl ester (WCMEE) produced was assessed for its thermal and physicochemical qualities in compliance with ASTM D6751 requirements. The intriguing discovery that WCMEE are more fuel-efficient than fatty methyl esters is due to the presence of ethyl esters. According to the results, adding 10% chicken fat biodiesel did not appreciably alter engine torque, but because biodiesel has a lower heating value, specific fuel consumption rose by 6.3%. The peak pressure inside the cylinder increased significantly, and combustion began sooner. While NOx emissions rose by 10%, CO and HC emissions fell by 15% and 10%, respectively.

This study addresses complementary treatment systems' economic feasibility and environmental benefits to reduce pharmaceutical micropollutants in urban water supplies in Curitiba, Brazil. The research evaluated powdered activated carbon (PAC) dosing systems in drinking water treatment plants (DWTPs), analyzing implementation and operational costs in relation to the environmental benefits represented by the shadow price of removed pharmaceutical micropollutants. The results indicate that while technically viable, the high cost of PAC systems renders the project economically unfeasible, with a removal cost of US$1.3941 per mg/L of micropollutant, far exceeding the estimated environmental benefit of US$0.4134 per mg/L. Over a 30-year horizon, the cost per m³ of treated water with PAC accounts for approximately 78.52% of the cost of a conventional DWTP, emphasizing the need for alternative funding models. The study highlights the critical importance of integrating environmental benefits into economic analyses and proposes an industry-financed fund by pharmaceutical companies to support the modernization of these systems, aligning with principles of social and environmental justice.

In this study, polysulfone capsules impregnated with the ionic liquid tetradecyltrihexylphosphonium decanoate (IC) were synthesized and applied to remove the reactive dye black (RB) an aqueous solution. The impregnated capsules were characterized by scanning electron microscopy (SEM), surface analysis by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). Some adsorption parameters were investigated, such as the effect of adsorbent dosage (0.01-1.5 g/30 mL), pH (2-12), and temperature (293-323 K). At pH 8, the dye was completely removed and the process was characterized as exothermic. The kinetic model that best represented the adsorption of RB was the pseudo-first-order. The analysis of the variation of the dye concentration (150-1000 mg L^-1) was performed and the Langmuir, Freundlich, and Redlich-Peterson models were presented in their nonlinear form. The maximum adsorption capacity identified by the Langmuir model was $q_{\max }$ of 276.94 mg g^-1, and the capsules could be reused for up to 4 cycles, showing removal percentages above 50% and cumulative loading of 520.8 mg g^-1. In addition, a fixed bed column adsorption study was carried out. These results indicate that the proposed material has a high adsorptive capacity and has potential for application in the treatment of industrial textile effluents containing reactive dyes. In addition to considerably reducing the toxic effects of the dye on Lactuca sativa, when compared with pure IL.

Green hydrogen from renewable resources is one of the most critical levers for counteracting global warming caused by anthropogenic greenhouse gas emissions and, at the same time, increasing energy security. Green hydrogen is about to move from an early innovation stage to an industrial scale. Leaders can shape this transition using ecosystem theory. We used an exploratory mixed-methods study design to investigate the architecture of such an ecosystem with actors and the characteristics with objectives, roles, and key activities. We interviewed in the first step 22 experts using a semi-structured interview guide and facilitated in the second step a focus group discussion with 24 participants to test the insights gained from the expert interviews for their practicality. The data analyzed by qualitative content analysis revealed four main actor segments sufficient to describe participation in the green hydrogen ecosystem (GHE). The focus group discussion adds a fifth group, which could be described as the central expert council actor segment, which optimizes the processes between the actors, emphasizing that all actor segments are pursuing a common objective, the decarbonization under the Paris Agreement from 2015. Three actor segments in the ecosystem are identified as leaders to realize the common objective: equipment and service providers, governments and authorities, and the hydrogen market. The subjective perception of a low return on investment, considering the efforts an actor needs to contribute to the joint value creation and the achievement of the actor's individual objectives, is with the actor segments with the leadership responsibility. In the medium to long term, this could lead to tensions and an imbalance in the ecosystem, which could be mitigated by a more transparent distribution and allocation of key activities in proportion to the achievement of objectives.

This study explores the causes of the acidic nature of the metal-rich, dilute groundwaters in the highland area of Ho Chi Minh City (HCMC), which is populated and mostly used for domestic, agricultural, and industrial purposes. The groundwater is generally very dilute (176 ± 128 µS/cm in electrical conductivity, 70 ± 220 µeq/L in alkalinity), but high in redox potential (343 ± 55 mV), and nitrate concentrations (19 ± 19 mg/L). Since the area corresponds to the highland and, thus, serves as a groundwater recharge zone. However, 53% and 90% of the investigated groundwater samples (n = 58) showed pH lower than 4 and 5, respectively, and, thus, 43%, 21%, and 7% of groundwater samples showed Al, Pb, and Cr concentrations exceeding their respective drinking water standards recommended by World Health Organization. Although nitrification is the most common acidification driver in the agricultural and/or urbanized lands, the nitrate concentration in this study area is strangely low compared to similar acidic groundwaters reported from other agricultural regions. To find out the causes of acidification, this study investigated the geochemical processes from the extensive groundwater chemistry data and performed geochemical simulations by changing water alkalinity and cation exchange capacity (CEC) of sediment and matching the results with the observed water chemistry data to confirm our hypothesis. Based on this approach, we could reveal that groundwaters of this study could become very acidic due to its dilute nature and low sediment CEC. Since groundwaters are generally very dilute in the recharge area, our finding provides another reason for the discreet management of highland areas where groundwater recharge is concentrated.