24年12月21日文献情报（15篇）

24年12月21日文献情报

1. 题目: Enhancing electricity generation and pollutant degradation in microbial fuel cells using cyanobacteria-derived biochar electrodes

文章编号: N24122115
期刊: Bioresource Technology
作者: Wentao Zhang, Daifei Xu, Yue Zhao, Degui Gao, Zhaotian Xie, Xinming Zhang, Bingdang Wu, Tianyin Huang, Lele Peng
更新时间: 2024-12-21
摘要: Utilizing microbial fuel cells (MFCs) technology to simultaneously achieve efficient biopower generation and pollutant degradation is a persistent pursuit. However, the limited rate of extracellular electron transfer (EET) and the availability of electrode materials remain key factors limiting the practical application of MFCs. In this article, modified carbon derived from cyanobacteria is applied to modify electrodes and assemble MFCs. By outputting voltage, power density, chemical oxygen demand removal rate and Coulombic efficiency the excellent bioelectricity performance of the assembled MFCs is demonstrated. The degradation performance of the assembled MFCs on various typical pollutants represented by tetracycline is illuminated, even up to 95.12%. Moreover, the pollutant removal mechanism by assembled MFCs is elucidated, including biofilm community and degradation pathway analysis. In a word, the enhanced EET process and high accessibility make the proposed MFC anode have fascinating application prospects in achieving efficient biopower generation and pollutant degradation simultaneously.
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2. 题目: Interpreting Machine Learning Predictions of Pb2+ Adsorption onto Biochars Produced by a Fluidized Bed System

文章编号: N24122114
期刊: Journal of Cleaner Production
作者: Suya Shi, Yaji Huang, Han Shen, Tengfei Zheng, Xinye Wang, Mengzhu Yu, Lingqin Liu
更新时间: 2024-12-21
摘要: Employing machine learning to predict the Pb²⁺ adsorption capacity of biochars is an innovative pursuit in hazardous materials. This study compared artificial neural network (ANN), support vector regression (SVR) and random forest (RF) for Pb²⁺ adsorption capacity by biochar from a fluidized bed system. Besides developing correlations for comparison, the RF model (R² = 0.984, RMSE=0.054) outperformed both ANN (R² = 0.908, RMSE=0.316) and SVR (R² =0.667) in predicting higher adsorption capacity. Based on the superior performance, the Shapley Additive Explanations (SHAP) were employed on RF. SHAP global explanations indicated that adsorption conditions contributed 69.03% and biochar characteristics contributed 30.21%to adsorption capacity, highlighting Dosage (D) and Carbon (C) as the crucial factors. Regarding biochar characteristics, element compositions contributed 76.59%. The single samples demonstrated that the final predictions align with the experimental results. The synergistic effect of dependence plot explains the Pb²⁺ adsorption under varying parameter conditions, such as D<1g/L, C<45%, Pb_in>100mg/L, H<2.5, t>12h, T>25°C, pH>9, H/C>0.4, the SHAP value is positive, contributing to an increase in adsorption capacity. Furthermore, a graphical user interface (GUI) leveraging SHAP model parameters predicts adsorbent performance, providing novel insights into optimizing biochars production. The obtained findings narrow the search for optimal biochars adsorbents and might guide laboratory experiments and engineering application of Pb²⁺ removal using biochars.
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3. 题目: Land use change effect on organic matter dynamics and soil carbon sequestration in the Brazilian Cerrado: A study case in Mato Grosso do Sul state (Midwest-Brazil)

文章编号: N24122113
期刊: Catena
作者: Fernanda Figueiredo Granja Dorilêo Leite, Ademir Fontana, Gabriel Nuto Nóbrega, Felipe Martini Santos, Bruno José Rodrigues Alves, Júlia Graziela da Silveira, Renato Campello Cordeiro, Carlos Eduardo Pellegrino Cerri, Rosemery Alesandra Firmino dos Santos, Renato de Aragão Ribeiro Rodrigues
更新时间: 2024-12-21
摘要: Pasture restoration and conservative agricultural practices, such as those used in Integrated Crop-Livestock-Forestry Systems (ICLF), can enhance soil protection and SOC stocks. This study, conducted in the Mato Grosso do Sul state, aimed to analyze the effect of land use conversion on C and N stocks and Soil Organic Matter (SOM) fractions to comprehend the C and N dynamic in 1-meter depth. Soil samples were collected in five different land uses in adjacent areas on the same farm: (1) Native Vegetation (NV); (2) Extensive Pasture (EP); (3) Managed Pasture (MP); (4) Integrated Crop-Livestock (ICL); and (5) Integrated Livestock-Forestry (ILF). Disturbed soil samples were collected using a soil auger at seven soil depthsfor elemental and isotopic analysis for soil C and N. Undisturbed samples were collected to assess the soil bulk density. The soil physical fractionationobtainedthe Particular Organic Matter (POM) and Mineral Associated Organic Matter (MAOM). The C and N stock varied from 86.02 in MP and 67.37 Mg ha⁻¹in ICL and was statistically similar for all studied land uses. The δ¹³C signature varied between land uses and through the soil profile, with more negative values for NV and ILF (−27.83 and −21.73 ‰, respectively) in the topsoil. The POM fraction indicated changes in land use, and the POM in ICL shows the potential to restore soil C and health since it is just in the second year of intervention. The managed pastures withgrass speciesBrachiaria promoted better soil C and N content and stocks.This studypointed out other alternatives to land use, such as integrated systems (ICL and ILF), which should be the target for the Brazilian policies to mitigate greenhouse gas emissions and enhance the diversification and resilience of the agroecosystem.
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4. 题目: Nitrogen-driven shifts in molecular composition of soil dissolved organic matter linked to rare bacterial sub-communities

文章编号: N24122112
期刊: Science of the Total Environment
作者: Xiaochun Yuan, Quanxin Zeng, Xinyu Bai, Xiaoqing Zhang, Xiaoting Fu, Mengxiao Ren, Juyan Cui, Qiufang Zhang, Xiaoli Gao, Jiacong Zhou, Yong Zheng, Kaimiao Lin, Yuehmin Chen
更新时间: 2024-12-21
摘要: The interaction between soil dissolved organic matter (DOM) and bacterial communities is critical for understanding key processes in the global carbon cycle. However, the molecular-level associations between these components remain poorly understood. To address this gap, high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was combined with high-throughput sequencing to examine how DOM composition and bacterial sub-community diversity respond to different levels of nitrogen (N) addition (0, 40, and 80 kg N ha⁻¹ yr⁻¹) and to explore the relationships between them. The results demonstrate a significant decline in carbohydrate molecules within DOM under low N conditions. Conversely, the β-diversity and double bond equivalents of DOM molecules increased, indicating greater heterogeneity and stability in DOM composition under this treatment. Rare bacterial sub-communities, as opposed to abundant taxa, were more sensitive to N addition, exhibiting narrower ecological niches and weaker phylogenetic signals. β-Diversity decomposition analysis indicated that compositional differences in abundant taxa were primarily driven by richness differences, whereas those in rare taxa were predominantly influenced by species replacement. Co-occurrence network analysis revealed that DOM molecules were more frequently linked with rare taxa than with abundant taxa. Furthermore, a strong positive relationship was observed between the β-diversity of rare taxa and that of DOM molecules along the N gradient. These findings underscore that rare bacterial sub-communities are the primary drivers of changes in DOM molecular composition under N enrichment, emphasizing their potential role in shaping chemical diversity.
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5. 题目: Investigation of adsorption parameters of saxitoxin onto loblolly pine-derived biochar synthesized at various pyrolysis temperature

文章编号: N24122111
期刊: Chemosphere
作者: Cadianne Chambers, Savannah Grimes, Russell C Smith, Ayden Weil, M Toufiq Reza
更新时间: 2024-12-21
摘要: This study highlights the use of loblolly pine derived biochar for the removal of harmful algal bloom toxin, Saxitoxin (STX), from water. Biochar samples were prepared at varying pyrolysis temperatures (400, 600 and 800 °C) for 60 min. As pyrolysis temperature increases, enhancement in surface porosity was observed (S_BET = 7.26 ± 0.2 m²/g to 408.15 ± 6.19 m²/g) while a decline in oxygen-containing functional groups was observed (1517.80 ± 14.98 μmol/g to 823.01 ± 7.72 μmol/g). This study aimed to discover the effects of adsorption parameters such as biochar dosage amount, contact time, initial concentration and initial pH on Saxitoxin adsorption. These studies revealed impressive results with >90 % toxin removal with dosage rate of 0.01 g/L, contact time of 30 min, and increasing percent removal with increasing initial STX concentration and initial pH in water. Maximum uptake was calculated for P400 with adsorption capacity of 314.37 μg/g. This showed that surface functionality showed higher affinity for STX uptake, which may be possible due to hydrogen bonding, electrostatic interactions, ion-exchange, and π-π interactions. Applied kinetic models indicated both physisorption and chemisorption interactions with best fit supporting the Elovich models. Complementary, adsorption isotherm analysis confirmed the multilayer adsorption behavior of the Freundlich model. Therefore, these findings support the viable use of biochar material for the remediation of STX waters.
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6. 题目: Effects of biochar on soil contaminated by metals and metalloids from slag disposal of an old environmental liability in Ribeira Valley, Brazil

文章编号: N24122110
期刊: Journal of Environmental Management
作者: Jacqueline Zanin Lima, Valéria Guimarães Silvestre Rodrigues
更新时间: 2024-12-21
摘要: Contamination with potentially toxic metals and metalloids (PTMs) in mining areas poses significant environment and human health risks. Using biochar as an amendment can be a cost-effective and eco-friendly method to reduce PTM bioavailability in contaminated soils, thus lowering plant uptake. This study investigated biochar derived from the organic fraction of municipal solid waste (OFMSW) at three pyrolysis temperatures (300, 500, and 700 °C) and two application rates (1% and 5%, w/w) for the remediation of slag-contaminated soils from an old environmental liability in the Ribeira Valley (Brazil). The results showed Zn > Pb > Cu > As > Co > Cr > Cd > Ni pseudo-total concentrations in slag with concentrations of As, Cu, Pb, and Cd posing greater environmental risks due to their toxicity. The biochar addition exerted limited effects on chemical fractionation, likely due to soil alkalinity, and BC300 5% increased As availability. A 1% biochar addition improved maize (Zea mays) growth, whereas 5% BC500 and BC700 were phytotoxic. The highest bioconcentration factor (BCF) values were observed for Cr, Cu, Ni, and Zn, which are all essential nutrients for plants; however, translocation factor (TF) from roots to shoots was generally low. A combination of BCF and TF < 1 suggested mechanisms limiting PTM uptake and translocation in plants. Pb showed a high ecological risk potential (${\mathrm{<span\; style="font-size:\; 15px;">E</span>}}_{\mathrm{<span\; style="font-size:\; 15px;">r</span>}}^{\mathrm{<span\; style="font-size:\; 15px;">i</span>}}$), with hazard quotients (HQ) exceeding 1 for the slag. BC700 5% provided the most promising ${\mathrm{<span\; style="font-size:\; 15px;">E</span>}}_{\mathrm{<span\; style="font-size:\; 15px;">r</span>}}^{\mathrm{<span\; style="font-size:\; 15px;">i</span>}}$ for As, Pb, and Zn; however, it proved toxic to maize, highlighting the need for multidisciplinary research and biochar's potential in site remediation. Further treatments are necessary for enhancing the retention efficiency or exploring combinations with other organic or inorganic amendments.
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7. 题目: The development of multifunctional biochar with NiFe2O4 for the adsorption of Cd (II) from water systems: The kinetics, thermodynamics, and regeneration

文章编号: N24122109
期刊: Journal of Environmental Management
作者: Makhosazana Masuku, Jemal Fito Nure, Harrison I Atagana, Ntuthuko Hlongwa, Thabo T I Nkambule
更新时间: 2024-12-21
摘要: High concentrations of Cd (II) in wastewater have been reported several times which attracted top research attention to mitigate the pollution impacts of the contaminant. Therefore, this study aimed to develop a Zn-doped NiFe2O4⁻ pinecone biochar composite (ZNiF@PB) for the adsorption of Cd (II) from wastewater. FTIR confirmed immobilization of PB on the surface of ZNiF by the presence of C = O at 1638 cm⁻¹, COOH at 1385 cm⁻¹, C-O at 1009 cm⁻¹ and Fe-O at 756 cm⁻¹. Similarly, XRD determined the crystallite structure of the adsorbents where the ZNiF crystallite size of 43 nm was obtained while the particle size of ZNiF@PB was found to be 38 nm. These XRD results agreed with those values obtained from TEM images showing ZNiF and ZNiF@PB had a spherical shape with similar particle sizes. On the other hand, the surface areas of ZNiF, PB, and ZNiF@PB were found to be 78.4 m²/g, 125 m²/g, and 104 m²/g, respectively. These high surface areas have a huge potential to enhance Cd removal. With these adsorbents, the maximum Cd (II) adsorption of 96% was recorded at the optimum experimental condition of adsorbent dosage 0.5g/50 mL, solution pH 6, initial Cd (II) concentration 100 mg/L, and contact time 120 min. Practical adsorption kinetics data were well described by the pseudo-second order model whereas the adsorption isotherm was a perfect fit to the Langmuir isothermal model implying the adsorption process to be a monolayer with mainly a chemically bonded mechanism. In conclusion, this adsorbent is efficient for the adsorption of Cd (II) from wastewater and has also a huge potential to be applied for industrial-scale water purification.
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8. 题目: Promoting the recovery of soil health in As and Sb-polluted soils: new evidence from the biochar-compost option

文章编号: N24122108
期刊: Environmental Science and Pollution Research
作者: Amina Boukhatem, Oualida Rached, Alima Bentellis, Sotirios Vasileiadis, Paola Castaldi, Giovanni Garau, Stefania Diquattro
更新时间: 2024-12-21
摘要:

The role of compost and biochar in the recovery of As and Sb-polluted soils is poorly investigated, as well as the influence of their application rates on soil health and quality. In this study, we therefore investigated the effectiveness over time (2, 4, and 6 months, M) of a municipal solid waste compost (MSWC) and a biochar (BC), applied at 10 and 30% rates, and of selected mixtures (MIX; applied at 10 and 30% total rates, 1:1 ratio of MSWC and BC), on labile As and Sb in a polluted soil from an abandoned Sb mine (Djebel Hamimat, Algeria). At the same timepoints, the amendment impact on soil chemistry was also monitored, while the activity and diversity of the resident microbial communities were investigated at 6 M. After 6 months, MSWC, BC, and MIX applied at the higher rate significantly increased soil pH (from 7.5 up to 8.2), while MSWC and MIX increased soil EC to worrying values. The soil dissolved organic carbon content was also greatly increased by MSWC and MIX at the higher rates (up to 50-fold), while BC showed a negligible impact. All the amendments reduced the concentration of labile Sb in soil, with BC 10% being the most effective treatment (i.e., reducing labile Sb from ~ 60 to 20 mg kg⁻¹ soil). On the contrary, only BC and MIX applied at 10% significantly reduced labile As (e.g., from ~ 12 to 4 mg kg⁻¹ soil in the case of BC). MSWC and MIX at both rates increased up to 2000-fold soil dehydrogenase activity, while BC showed a null impact. The Biolog community level physiological profile and sequencing of the partial 16S rRNA gene showed a reduction of catabolic activity and α-diversity and a change of the community composition of bacterial populations in treated soils. Overall, MIX treatment, especially at 10%, was the most promising option for the chemical and biological recovery of As and Sb-polluted soils.

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9. 题目: No saturation of soil carbon under long-term extreme manure additions

文章编号: N24122107
期刊: Plant and Soil
作者: Henrike Heinemann, Axel Don, Christopher Poeplau, Ines Merbach, Thorsten Reinsch, Gerhard Welp, Cora Vos
更新时间: 2024-12-21
摘要:

Background and aims

According to the carbon (C) saturation concept, the capacity of soils to accumulate stabilized organic C is limited by the number of binding sites on mineral surfaces. The concept and its application are highly debated. Therefore, we aimed at testing this theory using field experimental data.

Methods

Soils were sampled from four long-term field experiments with different amounts of organic fertilisation going up to extreme high C inputs (20 Mg C ha⁻¹ yr⁻¹) five times higher than in common agricultural practice. Soils were fractionated by particle size to obtain sand-sized, coarse silt and fine silt plus clay fractions.

Results

We found a linear relation between C input and soil organic carbon stocks (SOC) even with vast amounts of organic C inputs to the soil at three experimental sites. Across all experiments, C stocks in the sand-sized fraction increased on average by 146%, whereas C stocks in the fine silt plus clay fraction (< 20 µm) increased by just 17% without distinct saturation behaviour. The C sequestration efficiency (amount of C retained as SOC per amount of C input) tended to increase with initial SOC content which is not in line with the saturation theory.

Conclusion

The experiments were subject to C inputs via organic fertilisation that would and should rarely be reached in agricultural practice due to negative side effects. Even under these artificial conditions experiments did not show a distinct saturation behaviour.

Initial SOC stocks or SOC in the mineral-associated fraction did not appear to limit the potential of soils to sequester additional SOC. It can be concluded that C sequestration is mainly limited by the availability of C inputs from biomass.

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10. 题目: Ammonia nitrogen affects bacterial virulence and conditional pathogenic bacterial growth by regulating biofilm microbial metabolism and EPS secretion in laboratory scale distribution systems

文章编号: N24122106
期刊: Science of the Total Environment
作者: Huifang Sun, Xiurong Ju, Haibo Wang, Xu Ma, Baoyou Shi
更新时间: 2024-12-21
摘要: The control of conditional pathogenic bacteria and inhibition of their virulence factors (VFs) in drinking water distribution systems (DWDSs) is vital for drinking water safety. This study adopted two groups of DWDSs to investigate how ammonia nitrogen affects bacterial VFs and conditional pathogenic bacterial growth in biofilms. Our results indicated that Acidimicrobium (95,916.62 ± 119.24 TPM), Limnohabitans (30,338.81 ± 139.14 TPM), and Sediminibacterium (10,658.01 ± 48.94 TPM) were predominant in the biofilm bacterial community of DWDSs with NH3-N addition. Under these conditions, the abundances of various bacterial metabolites, such as L-glutamate (1.45-fold), 2-oxoglutarate (1.24-fold), pyruvate (2.10-fold), and adenosine monophosphate (AMP, 5.29-fold), were significantly upregulated, which suggested the upregulation of amino acid, carbohydrate, nucleotide, lipid, pyrimidine and purine metabolism. These metabolic pathways accelerated extracellular polymeric substance (EPS) secretion. The protein concentration in EPS also increased to 187.59 ± 0.58 μg/cm². The increased EPS secretion promoted the amide I CO group of the EPS protein to interact with the surface of the DWDSs, thus enhancing the ability of bacteria (especially conditional pathogenic bacteria) to adhere to the pipe surface to form biofilms. Due to EPS protection, the abundance of the adherence subtype of VFs and the plate counts of Pseudomonas aeruginosa increased to 5912.8 ± 21.89 TPM and 655.78 ± 27.10 CFU/cm², respectively. Therefore, NH3-N in DWDSs increased bacterial VFs levels and promoted the growth of some conditional pathogenic bacteria by regulating biofilm microbial metabolic pathways and EPS secretion, ultimately impacting the interaction between EPS and the pipe surface.
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11. 题目: The Impact of Different Functional Groups of Biochar on Mercury Adsorption Investigated by Density Functional Theory

文章编号: N24122105
期刊: Journal of Cleaner Production
作者: Kexin Chen, Jinying Li, Yuxuan Zhang, Bin Chen
更新时间: 2024-12-21
摘要: Investigating the impact of biochar functional groups on mercury adsorption performance can provide theoretical guidance for the search and design of high-performance mercury adsorbents. However, due to the highly heterogeneous nature, structural diversity, and surface complexity of biochar, current experimental techniques struggle to elucidate the detailed effects and mechanisms of each functional group. This study employs Density Functional Theory and wavefunction analysis methods to construct eight molecular models with different single and dual functional groups. We calculated and analyzed the adsorption energy, C-Hg bond length, charge transfer, surface electrostatic potential, and electron localization function for each model and adsorption site. Using these methods, we investigated the effects of -CH₃, -CH₂OH, hydroxyl, and cyano groups on mercury adsorption performance at various sites on carbon surfaces. The results indicate that cyano groups significantly enhance mercury adsorption, while hydroxyl groups exhibit specific effects at different sites. Additionally, we proposed interaction mechanisms for two types of dual functional groups—linear superposition and synergistic effects. This study addresses the current gap in understanding the properties of functional groups related to mercury adsorption and provides a more comprehensive theoretical basis for technologies aimed at efficient mercury adsorption under complex practical conditions.
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12. 题目: The efficacy of bioretention systems amended with iron-modified biochar for the source-separated and component-specific treatment of rainwater runoff: A microbiome perspective

文章编号: N24122104
期刊: Journal of Environmental Management
作者: Longfei Wang, Yuan Tian, Jie Sun, Yi Li, Zhengjian Yang
更新时间: 2024-12-21
摘要: Bioretention systems offer advantages in controlling non-point source pollution from runoff rainwater. However, the systems frequently encounter challenges, including insufficient stability of nitrogen and phosphorus removal. Limited research has been performed on bioretention systems which integrate actual data from non-point source pollution cases for the quantitative and qualitative refinement of initial and non-initial rainwater. Moreover, the potential linkages between amended media and microbial communities in bioretention systems with the addition of novel functional filler have not been explored. In this study, a system for treating both initial and non-initial rainwater was established through measurements including iron-modified biochar (FeBC) packing and the optimization of the layer structures. In system treating initial rainwater, the systems loaded with FeBC maintained stable NH4⁺-N and NO3⁻-N removal rates of over 95% and 80%, respectively under 12 rainfall simulation events. After a 10-day antecedent drying duration (ADD), the removal rates for NH4⁺-N and PO4^3--P remained above 78% and 85%. In systems designed to process non-initial rainwater, increasing the height of the transition layer effectively enhanced the NH4⁺-N removal stability. Meanwhile, increasing the height of the drainage layer could promote PO4^3--P removal rates to over 75%. The addition of FeBC facilitated the growth of certain denitrifiers improved overall NO3⁻-N removal during successive rainfall events. The microbial communities may adapt to variations in the external environment by enhancing the synthesis of ribosome and the metabolism of pyrimidine and purine, further improving the stability of NH4⁺-N removal. This study provides a theoretical basis for the precise enhancement of nitrogen and phosphorus removal and the design of bioretention systems for differentiated treatment of rainwater, guiding their design and applications in different regions.
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13. 题目: TG-MS Analysis for Elemental Composition of Organic Matters and Their Structural Properties

文章编号: N24122103
期刊: Analytical Chemistry
作者: Lin Lin, Sasha Yang, Fuhong Zhang, Muxin Liu, Dong Liu, Lei Shi
更新时间: 2024-12-21
摘要: A novel approach for determining the elemental content of organic matter through thermal gravimetric analysis coupled online with a mass spectrometer (TG-MS) is disclosed. This method not only yields results equivalent to ASTM analysis but also provides insight into the covalent bond structure within the sample. The principle of this technique consists of the combustion of organic matter in an oxygen-enriched environment within the thermogravimetric (TG) system. The gases generated during combustion, including carbon-containing gases such as CO₂ and CO, hydrogen-containing gases such as H₂O, nitrogen-containing gases such as NO₂ and NO, and sulfur-containing gases such as SO₂, are then analyzed using online MS. Quantitative analysis of these gases is accomplished via an external standard method, facilitating the determination of the elemental content of the organic matters. The experiment employed a temperature-programmed heating rate of 10 °C/min, a carrier gas flow rate of 100 mL/min, and an oxygen concentration of 50% by volume. We conducted tests on a range of 23 samples, including coal, heavy oil, oil shale, and biomass. The results for coal, oil shale, and biomass samples were consistent with ASTM standards, while the heavy oil samples demonstrated slightly lower values compared with ASTM methods. Furthermore, we probed into the mass loss and gas generation processes that occur during the combustion of samples, and these results enhance the understanding of the mechanism of organic matter combustion as well as that of the covalent bond structure of organic matters.
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14. 题目: Photochemistry of dissolved organic matter derived from compost

文章编号: N24122102
期刊: Science of the Total Environment
作者: Ziling Xiao, Jingyan Zhang, Yilang Qin, Bin Xi, Xiangyang Zhou, Xiuna Ren, Quan Wang
更新时间: 2024-12-21
摘要: The extensive application of compost to enhance soil quality highlights the crucial role of dissolved organic matter (DOM) derived from compost in both terrestrial and aquatic ecosystems, influencing carbon cycling and the fate of contaminants. However, the photochemical behavior of compost-derived DOM (DOMCOM) remains poorly understood. In this study, we investigated the photochemical transformation and photoactivity of DOM derived from typical composts produced from cow manure (CDOM) and pig manure (PDOM). The results indicated that the initial CDOM exhibited higher molecular weight, aromaticity, humification, and photoactivity compared to PDOM. Under UV irradiation, both DOMCOM underwent photobleaching and photo-humification, resulting in a decrease in the average molecular weight by 23.68 % for CDOM and 3.82 % for PDOM, with CDOM being particularly affected. Meanwhile, 2D-COS analysis revealed that the fulvic-like fluorescence fraction was first to respond to photoirradiation in both DOM, followed by the protein-like and microbial humic-like fluorescence fractions, which showed contrasting response trends in CDOM and PDOM. Furthermore, CDOM with a higher concentration of humic-like substances efficiently generated ³DOM*, ¹O2 and ^•OH (4.09 × 10⁻⁸, 1.17 × 10⁻⁸ and 7.05 × 10⁻¹², respectively) under UV radiation, which were apparently greater than those produced by PDOM (3.30 × 10⁻⁸, 8.38 × 10⁻⁹ and 4.99 × 10⁻¹², respectively).
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15. 题目: Seasonal and spatial pattern of dissolved organic matter biodegradation and photodegradation in boreal humic waters

文章编号: N24122101
期刊: Biogeosciences
作者: Artem V Chupakov, Natalia V Neverova, Anna A Chupakova, Svetlana A Zabelina, Liudmila S Shirokova, Taissia Ya. Vorobyeva, Oleg S Pokrovsky
更新时间: 2024-12-21
摘要: . Studying the competitive effects of microbial and light-induced transformation of dissolved organic matter (DOM) and trace metals is crucially important for understanding the factors controlling aquatic carbon (C), micronutrient and toxicant transformation in boreal waters. Here we determined the biodegradability and photodegradability of DOM and their effects on the behavior of dissolved trace metals in humic surface waters from the European subarctic: an ombrotrophic peat bog continuum (subsurface water–peatland pool–stream) and a stratified forest lake across seasons. Along the bog water continuum, the biodegradation rate was the highest in subsurface waters and the lowest in the acidic peatland pool. Photodegradation was similar for subsurface waters and the stream but was not detectable in the peatland pool. The waters of the forest lake exhibited a strong seasonal effect of biodegradation, which was the highest in October and the lowest in June. Overall, the biodegradation was capable of removing between 1 % and 7 % of initial dissolved organic carbon (DOC), being the highest in the forest lake in October and in the peatland pool in summer. Photolysis was capable of degrading a much higher proportion of the initial DOC (10 %–25 %), especially in the forest lake during June and the bog stream during July. Only a few trace metals (TMs) were sizably affected by both photodegradation and biodegradation of DOM (Fe, Al, Ti, Nb and light rare-earth elements (REEs)), whereas V, Mn, Co, Cu and Ba were affected solely by biodegradation. A likely mechanism of metal removal was their co-precipitation with coagulating Fe(III) hydroxides. Compared to typical CO2 emissions from inland waters of the region, biodegradation of DOM can provide the totality of CO2 evasion from lake water surfaces, whereas biodegradation and photodegradation are not sufficient to explain the observed CO2 fluxes in the bog water continuum. Overall, these results demonstrated strong spatial and seasonal variability in biodegradation and photodegradation of DOM and organic TM complexes, and we call for the need for a systematic assessment of both processes across seasons with high spatial resolution.
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