Environmental Science and Pollution Research最新文献

This work explores the potential of waste materials as a source of renewable energy and valuable products through co-processing. It discusses the mixing, blending, co-pyrolysis, and co-gasification of low-rank coal (LRC), fecal sludge, and wastewater sludges, comprising domestic wastewater sludge (DOM), commercial wastewater sludge (COM), and industrial wastewater sludge (IND), to produce synthesis gas, NH₃, and H₂SO₄. The study examines and compares the syngas yields of each sample from the co-pyrolysis and co-gasification processes, while considering the effects of temperature and pressure at the first process and then evaluating the sensitivity analysis of the process with steam-to-biomass ratio and equivalence ratio during the second process through the methodological approach using ASPEN Plus. The simulation showed a higher gas yield than experiments (with an increase in N₂ yield at 500 °C), highlighting the benefit of co-pyrolysis. This modeling approach could function as a method for selecting samples based on temperature and pressure. The study found that co-gasification showed better syngas yields compared to co-pyrolysis. It was observed that some specimens are deficient in CO₂ and CH₄ yields at the co-gasification process. It also assessed the formation mechanisms of NH₃ and H₂SO₄, as well as the utilization of the H₂SO₄ produced through straw's acid hydrolysis. The LRC with fecal sludge and DOM/IND with LRC/COM produced the highest yields of H₂SO₄ and NH₃ at 5.26% and 69.52% respectively. The D-xylose formed from the hydrolysis is above 40%. The study suggests that co-processing waste materials for renewable energy and valuable products is promising.

The treatment and management of landfill leachate is challenging due to its complex and variable composition. To comply with regulations, reverse osmosis (RO) is applied as an advanced treatment for highly polluting leachate, considering its satisfying removal efficiencies. Still, operational drawbacks such as membrane fouling and concentrate management limit the full promotion of RO technology for leachate purification. This study presents the technical performance of a full-scale RO facility located at the Hamici landfill in Algeria. Leachate characteristics were assessed over 24 months from 2022 to 2023. Our work also evaluates the feasibility and limitations of RO technology, especially under high loads of organic compounds. The leachate had a high organic matter concentration, with chemical oxygen demand (COD) values ranging from 9940 to 21,500 mg L^-1, 5-day biochemical oxygen demand (BOD₅) from 1175 to 3666 mg L^-1, and ammonia nitrogen (NH₄⁺) levels reaching up to 3494 mg L^-1. Despite the fluctuations of the leachate's quality, the RO treatment maintained consistently satisfactory abatement, about 98% for COD, 90% for BOD₅, and 94% for NH₄⁺. However, membrane fouling was recurrent due to the high pollutant load of the leachate, resulting in repetitive downtimes and membrane replacement. Extensive and costly consumption of sulfuric acid (H₂SO₄, 98%), up to 12,800 kg per month for pH adjustment before the RO unit, chemicals for membrane cleaning, and high energy demand were identified as the primary operational challenges in the present case study. Additionally, the hydrogen sulfide (H₂S) emissions on-site and the RO's concentrate management need to be addressed to improve the sustainability of RO technology in the leachate treatment chain.

To investigate the dynamic properties of fiber-reinforced sand, this study used natural sand from the Tarim Basin in Xinjiang as the research object. Meanwhile, in response to the dual-carbon strategy, environmentally friendly and biodegradable natural biomass lignin fibers were selected as the modification material. Dynamic strength tests with different fiber contents were conducted via cyclic triaxial tests, and the liquefaction resistance and dynamic strength indices of the reinforced sand under different confining pressures, consolidation ratios, and vibration frequencies were comparatively analyzed. The results show that the fiber content and consolidation ratio significantly affect the dynamic strength of sand: with the increase in vibration frequency, the viscoelastic hysteresis effect of the fiber material weakens the improvement effect at high frequencies. Based on the test data, a multi-variable nonlinear model for the dynamic internal friction angle-considering fiber content (F_c), consolidation ratio (K_c), vibration frequency (f), and number of vibrations (N)-was established. The model has an R² of 0.980 and an RMSE of 0.794°. Verification results indicate that the model's prediction accuracy meets engineering requirements within the range of conventional parameters. The research findings can provide a theoretical basis for the seismic design of lignin fiber-reinforced sand foundations.

The propagation of plastic pollution has triggered widespread microplastics (MPs) contamination, increasingly being detected across diverse ecosystems, including agricultural landscapes. However, there is a critical knowledge gap regarding MP contamination in food crops cultivated near municipal waste dumping ground. Therefore, this study involves in investigating the occurrence and characterization of MPs in agricultural soil, vegetables (Cabbage, Chili, Brinjal, Spinach and Tomato), and their rinsed water samples. A total of 25 vegetable samples and 25 soil samples were collected from each field using a stratified design. In addition, 25 rinsed-water samples were obtained from the corresponding vegetable samples collected from the agricultural fields present in the vicinity of Dhapa dumpsite in Kolkata, India. The results of this study revealed that chili was highly contaminated with 19.00 ± 2.92 MPs g^-1 and cabbage was least contaminated with 10.20 ± 4.27 MPs g^-1. Polymeric profiling of the identified MPs revealed the presence of a varied range of polymers including polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE) with varying dominance patterns. Soil, rinsed water, and all vegetable exhibited polymer hazard Index (PHI) scores > 1000, corresponding to a level V hazard classification. Estimates of per day MP consumption (based on per capita consumption rate) indicates that spinach is associated with higher levels of MP consumption, while tomato and chilies contribute to lower levels in both rural and urban populations. The results underscore potential risks to human upon exposure, highlighting the urgent need for mitigation approaches, regulatory frameworks on dumping wastes, and sustainable agricultural practices to reduce MP contamination in food chain.

The air pollution tolerance index (APTI) and the anticipated performance index (API) are crucial indices for selecting plant species suitable for green belt development in polluted areas. The APTI of plants is related to changes in the total chlorophyll (TC), total ascorbic acid (TAC), relative water content (RWC) and pH of leaf extract (PLE) due to the dust accumulation (DA) on the leaves. In addition, the API of a plant includes its APTI value along with morphological characteristics and economic value that provide an assessment of a plant's suitability for plantation in polluted areas. This research aims to find pollution-tolerant tree species using the APTI and API as tool indices. In polluted areas, TAC increases with increasing DA on the leaves, but TC, PLE and RWC did not show a definite increasing trend. Based on APTI and API scores, Ficus benghalensis is classified as an excellent performer, Ficus religiosa, Mangifera indica and Syzygium cumini are considered very good performers and Eucalyptus globulus is rated as a good performer in response to DA. Accordingly, these plant species could be recommended for plantation in and around urban cities in tropical areas to support the development of urban forests and green belts, thereby contributing to the mitigation of air pollution.

This study presents the synthesis and characterization of rGO/CS/Ag nanozyme, an artificial enzyme with peroxidase-like activity. A complex nanozyme composed of reduced graphene oxide (rGO), silver (Ag), and chitosan (CS) is reported in this study for the first time as a catalyst material and synthetic enzyme for detecting the carbaryl pesticide. FTIR analysis confirmed the reduction of graphene oxide (GO) to reduced graphene oxide (rGO) using urea, which removes oxygen-containing functional groups while still leaving some oxygen groups intact. XRD analysis showed a reduction in the interlayer spacing of rGO after reduction, with the nanozyme displaying a uniform distribution of Ag on the rGO surface. SEM and BET analysis revealed a mesoporous structure in the rGO/CS/Ag nanozyme, with a large surface area suitable for catalytic applications. The catalytic activity was tested using a TMB-H₂O₂ system, and the results showed good peroxidase activity, with the nanozyme showing a high affinity for the TMB substrate. Furthermore, inhibition studies using the pesticide carbaryl confirmed that the nanozyme operates through a non-competitive inhibition mechanism. Carbaryl detection was successfully achieved with a low detection limit (0.0036 mM), demonstrating the potential of this nanozyme for environmental monitoring and sensor applications. This study highlights the promising catalytic and detection capabilities of the rGO/CS/Ag nanozyme in various applications, including catalysis and sensing.

Utilization of agro-industrial wastes as soil amendment manages acidity, remediates heavy metals, and ensures environmental sustainability. The present study aims to test non-conventional organic Si sources, milled rice husk char (T_MRHC), and powdered diatomaceous earth (T_DE) against burnt lime (T_BL) and calcium silicate (T_CS) for amending iron (Fe) toxicity and acidity at tillering (TI), panicle initiation (PI), and harvest (HA) of a short duration rice variety Manuratna in lateritic rice wetlands of Kerala. Irrespective of the growth stages of rice, T_MRHC recorded the lowest water-soluble Fe (WS-Fe), acid-soluble Fe (AS-Fe), manganese oxide (MnO)-occluded Fe (MN-Fe), and residual Fe (RS-Fe) fraction in soil. WS-Fe indirectly enhanced Fe adsorption into specifically adsorbed lead displaceable Fe (SP-Fe) and AS-Fe, whereas AS-Fe abridged the Fe adsorption between WS-Fe and MN-Fe > OM-Fe. Organic Si sources recorded a strong negative influence on organic matter-occluded Fe (OM-Fe) (standardized path coefficient p = - 0.94), amorphous iron oxide (FeO)-occluded Fe (AM-Fe) (p = - 0.74), and crystalline FeO-occluded Fe (CR-Fe) (p = - 0.53) content in soil. Fractions of Fe and forms of acidity were significantly (p = 0.05) and positively correlated. T_BL maintained the highest soil pH at all the critical growth stages (5.90(TI), 6.04(PI), and 5.99(HA)) of rice, which was statistically on par with T_MRHC (5.90(TI), 6.02(PI), and 5.96(HA)). The highest reduction of Fe in rice was recorded with T_BL at TI (16%) and PI (18.76%), while at HI (21%), T_MRHC was found to the most effective. T_BL and T_MRHC were statistically on par in reducing WS-Fe (at PI and HA), exchangeable acidity and extractable acidity (at TI), and total acidity (at HI). The grain yield of Manuratna rice was found to vary in the order T_CS > T_MRHC and T_BL.

Microbial communities perform important roles in nutrient cycling, degradation of environmental pollutants, and support of various life forms on Earth. Mangroves live in very harsh environments, and if not for the existence of several microbial species in their ecosystems, they would not survive. The Egyptian Red Sea coast is dominated by two mangrove species, Avicennia marina and Rhizophora mucronata, which serve as breeding grounds for marine organisms and aid in carbon sequestration. Despite their ecological significance, comparative studies examining the physiochemical properties and heavy metal concentration of mangrove sediments of two dominant species along the Egyptian Red Sea coast (Hamata, Mangrove Bay, and Saffaga) and their relationship to microbial and functional diversity are scarce. Our findings revealed significant differences in sodium ions, potassium ions, organic carbon, and bulk density at 30-50 cm depth across the locations. Heavy metal analysis revealed significantly lower concentrations of zinc and manganese and high concentrations of copper in sediment samples collected from Mangrove Bay at all sampling depths. Metagenomics analysis revealed that the dominant phyla across the three sites were Pseudomonadota, Bacillota, and Bacteroidota, along with Actenomycetota, and Chloroflexota, and unclassified bacteria. Within the phylum Bacillota, several major classes were identified, including Bacillota_A_368345, Bacillota_I, and Bacillota_C. Functional prediction revealed a higher abundance of microbes involved in energy metabolism and carbon cycle, whereas a lower abundance of microbes involved in sulfur and nitrogen cycles was noted across the sites. In conclusion, the identification of different microbial communities in sediments collected along the Egyptian Red Sea coastal areas suggests the role of different mangrove species and human activities in recruiting unique microbial species involved in promoting their survival under different environmental factors.

Building material waste stored for long periods near agricultural lands and water resources may pose a danger to the environment and human health due to the toxic chemicals and metals they contain. Clay bricks (CBs), generally produced by mixing clay and water, are formed by firing the air-dried mixture to make them durable and stable. During firing, the CB suffers some chemical and physical changes and turns into a new artificial material. CBs, known as masonry units, have been one of the most used building materials throughout the history of construction. CB may naturally contain PTMs depending on the geochemical structure of the clay used in the production phase. In this study, major and minor oxides and PTM distributions in 45 CB samples collected from 31 CB factories that provide approximately one-third of the CB utilized in buildings in Türkiye were determined for the first time using an energy-dispersive X-ray fluorescence spectrometer. The average contents (in %, dry weight) of major and minor oxides in CB samples are in order of SiO₂ (49.9) > Al₂O₃ (17.8) > CaO (9.5) > MgO (8.2) > Fe₂O₃ (7.5) > SO₃ (3.6) > Na₂O (3.3) > K₂O (1.8) > TiO₂ (0.9) > P₂O₅ (0.2) > MnO (0.1). The average contents (in mg/kg dw) of Fe, Ti, Mn, Cr, Sr, V, Ni, Zr, Zn, Cu, Co, Pb, and As in CB samples were analyzed as 52779, 5329, 736, 341, 233, 192, 190, 110, 85, 44, 39, 14, and 8, respectively. According to the enrichment factor results based on the Earth's crust average, it was revealed that Cr, Ni, and As were naturally moderately enriched.

The rise in worldwide energy needs and growing environmental concerns necessitate the development of clean, renewable alternatives to fossil fuels. Co-pyrolysis of plastic waste and biomass provides a sustainable method for transforming waste into valuable fuel products. This study explores the engine performance, combustion behaviour, and emission properties of a single-cylinder, four-stroke compression ignition (CI) diesel engine fueled by blends of traditional diesel and co-pyrolytic oil produced through the co-pyrolysis of waste polypropylene (discarded saline bottles) and tamanu seed (Calophyllum inophyllum). Diesel was blended with 10%, 20%, 30%, and 40% co-pyrolytic oil by volume, labelled as B@10, B@20, B@30, and B@40, respectively, and tested in an unmodified diesel engine. Among the blends, B@40 exhibited the most promising performance, achieving a peak brake thermal efficiency (BTE) of 28.32% at full load, comparable to conventional diesel (D100). Moreover, B@40 exhibited a brake-specific fuel consumption (BSFC) of 0.29 kg/kWh, which is 14.7% lower than that of D100. B@30 demonstrated a slightly reduced exhaust gas temperature (EGT) of 328.78 °C, which was 0.99% lower than D100. CO and HC emissions increased with higher blend ratios but decreased with rising engine load, while NOx emissions declined with increasing blend ratios and rose with load. B@30 exhibited the most efficient emission performance, with CO, HC, and NOx emissions at 0.021%, 12%, and 189 ppm, respectively, showing a 5.9% reduction in NOx compared to D100. The blend also exhibited reduced heat release rates and in-cylinder pressure, reflecting improved combustion efficiency. These results demonstrate that co-pyrolytic oil is a promising, sustainable, and environmentally friendly substitute for conventional diesel fuel.