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1. 题目: Deciphering the Role of Biochar on Ammonia Oxidation with Bicarbonate as an Electron Acceptor: Complete Nitrification of NH4+-N to NO3⁻-N Under Short-term Low-temperature Stress
文章编号: N26031016
期刊: Water, Air, & Soil Pollution
作者: Ruilin Wang, Jingang Huang, Jingya Liu, Huanxuan Li, Rongbing Zhou, Wei Han, Xiaobin Xu, Xiaoping Fu, Haibo Wang
更新时间: 2026-03-10
摘要: To overcome challenges of energy-intensive nitrification and nitrite-limited anammox, this study developed a biochar-assisted anaerobic NH4+-N oxidation process using bicarbonate (HCO3⁻) as a potential electron acceptor. While the biochar-free system primarily accumulated NO2⁻-N, bamboo biochar enabled the complete nitrification to NO3⁻-N, even under low-temperature stress (12–15 °C). The prolonged operation under lower temperatures (< 12 °C) diminished this enhancement and reduced nitrification efficiency, with persistent effects even after temperature recovery to 25 °C. Morphological and 16S rRNA sequencing results revealed distinct microbial communities in this bicarbonate-driven system compared to conventional anammox sludge. Biochar enhanced the resilience of the system against low-temperature stress by selectively enriching specific taxa, such as nitrifying bacterium Nitrobacter and the functionally associated nxrB gene, both of which were critical for complete nitrification. Machine learning with XGBoost modeling effectively predicted the nitrite accumulation ratio (NAR) and nitrogen removal efficiency (NRE), identifying operating temperature as the significant positive factor. The negative contribution of biochar dosage to NAR prediction further confirmed its role in prompting complete nitrification. Overall, this study presents a promising complete nitrification process to address low-temperature stress and electron acceptor limitations in NH4+-N removal.

2. 题目: Differential effects of Phragmites australis versus Spartina alterniflora biochar on salt marsh soil improvement and carbon stabilization
文章编号: N26031015
期刊: Frontiers in Environmental Science
作者: Lin Xiaowen, Song Ge, Luo Xin, Lai Jianping, Zhang Weiting, Liu Jin-e, Huang Jinlou, Xu Shanshan, Waqas Khan, Sun Minnan, Bi Jing
更新时间: 2026-03-10
摘要: Biochar is an effective strategy for improving physicochemical properties of coastal salt marsh soil and enhancing carbon stabilization. In this study, Spartina alterniflora ( S . alterniflora ) and Phragmites australis ( P . australis ) were used as biochar materials. Four pyrolysis temperatures (350 °C, 450 °C, 550 °C, and 650 °C) and three addition amounts (1%, 2%, and 3%) were applied to explore the effects of the two biochars on the physicochemical properties and carbon components of salt marsh soil. The results showed that both S. alterniflora biochar (SBC) and P . australis biochar (PBC) significantly increased soil pH, cation exchange capacity, and nutrients (SBC: 5.3%–188.6%; PBC: 1.4%–200.9%). The addition of biochar at 3% significantly increased soil total nitrogen (TN), Nitrate nitrogen (NO 3 − ), and available phosphorus (AP) contents, thereby effectively enhancing soil nutrient supply capacity. The addition of SBC and PBC altered the composition of soil organic carbon (SOC), significantly increasing the proportion of mineral-associated organic carbon and thereby promoting SOC stability, particularly under high addition amounts and pyrolysis temperatures. These findings suggest that both SBC and PBC hold promise for improving soil carbon stabilization in coastal salt marsh soils. This study provides a valuable approach for saline–alkali soil remediation in coastal wetlands and offers a potential pathway for the resource utilization of S. alterniflora and P . australis .

3. 题目: Molecular interaction of pristine and photoaged polylactic acid microplastics with extracellular polymeric substances from Microcystis aeruginosa
文章编号: N26031014
期刊: Environmental Research
作者: Hongwei Luo, Zhen Li, Shizhe Xu, Chaolin Tu, Chenyang Liu, Dongqin He, Jianqiang Sun, Xiangliang Pan
更新时间: 2026-03-10
摘要: Microplastics (MPs) existence in aquatic environments may cause changes in properties of water bodies and associated sediments. In freshwater systems, most of the photosynthetic products of phytoplankton are released in the form of extracellular polymeric substances (EPS). EPS often interact with some charged particles through specific functional groups in their macromolecules. An in-depth understanding of EPS-MPs interactions is essential to assess the environmental effects of MPs on freshwater and marine systems. In this study, the mechanism behind the interactions of pristine and photoaged polylactic acid microplastics (PLA-MPs) with EPS was systematically investigated at the molecular scale. Results show that the addition of EPS remarkably enhanced the fluorescence intensity of humic- and fulvic-like substances within pristine and aged PLA as revealed by fluorescence excitation-emission matrix. Fourier transform infrared spectroscopy, Raman spectra, and atomic force microscopy coupled with infrared spectroscopy (AFM-IR) further demonstrated that interactions between EPS and pristine PLA were mainly via hydrogen bonding-induced local chain rearrangement or breakage. Meanwhile, aging of PLA led to the stronger interaction with EPS. Compared with pristine PLA, aged PLA exhibited more pronounced surface alteration and molecular weight reduction after exposure to EPS under the applied experimental conditions, suggesting a greater susceptibility to hydrolytic transformation. Moreover, the aged PLA displayed pronounced cracks and grooves, especially after reaction with EPS. EPS addition also increased the negative surface charge of PLA, especially in aged PLA. This study highlights the complexity of PLA-EPS interaction mechanisms, and offers a possible view on predicting the environmental behavior of MPs and regulating their biodegradation process.

4. 题目: Molecular Composition of Soil-Derived Dissolved Organic Matter Regulates Photodegradation of 6PPD-Quinone
文章编号: N26031013
期刊: Journal of Environmental Chemical Engineering
作者: Jiale Liu, Linbin Zhu, Hua Yin, Yibo Yuan, Yuhao Cai, Shaoyu Tang, Junfeng Niu
更新时间: 2026-03-10
摘要: The tire rubber antioxidant transformation product N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) has emerged as widespread contaminant, raising serious ecological concerns. Soil-derived dissolved organic matter (SDOM) is a major source of photochemically produced reactive intermediates (PPRIs) that mediate pollutant transformation in terrestrial environments. This study investigated 6PPD-Q photodegradation with different SDOM. The results revealed that SDOM significantly accelerated the photodegradation of 6PPD-Q, with black soil-derived DOM (BS-DOM) indicating a 49.5% increase, significantly higher than the 13.7% and 23.5% enhancements observed with yellow soil-derived DOM (YS-DOM) and red soil-derived DOM (RS-DOM), respectively. Electron paramagnetic resonance (EPR) and quenching experiments indicated that hydroxyl radicals (•OH) served as the primary reactive species responsible for 6PPD-Q degradation. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and spectroscopy analyses revealed that abundant lignin-like components and moderate sulfur contents in BS-DOM facilitated efficient •OH generation, thereby exerting the most significant accelerating effect on 6PPD-Q photodegradation. High-resolution orbitrap mass spectrometry further identified 22 intermediates, with hydroxylation, C-N bond cleavage, and quinone decomposition as the main degradation pathways, leading to less toxic products than the parent compound. These results underscore the critical role of DOM composition in 6PPD-Q photodegradation and offer fresh perspectives on the environmental fate of 6PPD-Q in soil-associated system.

5. 题目: Electrical Stimulation-Induced π-π Stacking Drives Sludge Humification to Enhance Direct Interspecies Electron Transfer and Methanogenesis
文章编号: N26031012
期刊: Water Research
作者: Lujun Wang, Zhihao Jiang, Qilin Yu, Yaobin Zhang
更新时间: 2026-03-10
摘要: Electrical stimulation has been applied to enhance anaerobic digestion (AD), but its underlying mechanisms remain unclear. This study reveals that electrical stimulation accelerates sludge humification during AD by driving π-π stacking of humic precursors, thereby enhancing electroactivity and methanogenesis. Specifically, methanogenic potential and HA content increased by 42% and 75.1%, respectively, compared to the control (without electrical stimulation). X-ray photoelectron spectroscopy (XPS) revealed intensified π-π stacking interactions in the electrical stimulation group. Density Functional Theory (DFT) calculations confirmed that the electric field induces strong polarization of humic precursors (dipole moment ∼21 Debye). This polarization significantly strengthens intermolecular noncovalent interactions (lowering binding energy by 25.63 kcal/mol), serving as the thermodynamic driving force for π-π stacking. Consequently, this supramolecular assembly forms an extensive delocalized electron system, reducing charge transfer resistance by 56% and facilitating Direct Interspecies Electron Transfer (DIET). Furthermore, for the first time, ¹³C isotope tracing confirmed a strong correlation (R²>0.88) between conductivity and DIET contribution. The findings of this study provide a novel perspective for understanding and optimizing bio-electrochemical systems.

6. 题目: Differentiated Carbon Stabilization Pathways Reveal Cropland Promotes MAOC in the Yellow River Sediment‐Affected Area
文章编号: N26031011
期刊: Land Degradation & Development
作者: Ran Wang, Junhua Zhang, Shu Liu, Xixi Sun, Shengxin Wang, Hua Shang, Yaping Zheng, Rubing Li, Ziqi Jiang, Guodong Li
更新时间: 2026-03-10
摘要: Soil organic carbon (SOC) fractions play a crucial role in regulating biogeochemical cycles and carbon sequestration processes. However, in ecologically fragile regions such as the Yellow River sediment‐affected area, the long‐term dynamics and turnover mechanisms of particulate organic carbon (POC) and mineral‐associated organic carbon (MAOC) under different land‐use types remain unclear. Based on the 2013 and 2023 field samples, we examined planted forests, cropland, and orchard soils in the Yellow River sediment‐affected region to quantify 0–40 cm soil layer decadal changes in POC and MAOC, their sequestration pathways, and key drivers. All land‐use types exhibited significant carbon accumulation but followed differentiated sequestration pathways. In cropland, the increase in MAOC (2.17 g kg −1 ) in the 0–20 cm layer was 2.1 times that of POC (1.03 g kg −1 ), and the proportion of MAOC increased markedly from 43% to 51%. Orchard soils exhibited the highest MAOC accumulation in the surface layer (3.63 g kg −1 ) but showed a loss of POC in the 20–40 cm layer (−0.91 g kg −1 ). Planted forests showed steady increases in both POC and MAOC. Analysis of driving factors revealed that vegetation inputs and soil properties were key determinants of surface POC dynamics, while soil properties, particularly total nitrogen content and soil particle size, primarily controlled MAOC stabilization. This study demonstrates that modern agricultural practices characterized by straw incorporation effectively promote the conversion of labile POC into stable MAOC, providing key scientific evidence to optimize land management and enhance soil health and carbon sequestration efficiency in coarse‐textured soils.

7. 题目: Carbon Storage Potential of Cultivated Soils Within Grassland Ecosystems Through a Benchmark Approach
文章编号: N26031010
期刊: Land Degradation & Development
作者: Azamat Suleymanov, Igor Rusakov
更新时间: 2026-03-10
摘要: Although soil organic carbon sequestration is a primary focus for mitigating the global carbon deficit, actionable strategies are hampered by insufficient knowledge of real‐world sequestration capacities. We aim to evaluate the total organic carbon (TOC) stocks across several land use types and define the storage potential of recent cropland and pasture using the native soils as a reference. Using the “Soil Health Gap” concept, we derived a threshold of 50% and target values of 80% and 100% of the average TOC stock under native soils and evaluated the storage potential. The native TOC stocks (mean = 228.3 t/ha) were higher than co‐located recent cropland (171 t/ha) and comparable with pasture (221.5 t/ha). Using the set targets, cropland has a potential for TOC storage of 12–13 t/ha to reach 80% and 55–65 t/ha to reach the full pristine reference mean. According to the threshold value, all samples and averages of TOC were above it. We demonstrated that the land use type significantly alters TOC stocks and that cropland soils have the highest potential for TOC storage. A cropland conversion depletes TOC stocks by 25% relative to native grasslands due to intensive agricultural practices that accelerate decomposition and reduced litter inputs, while pastures maintain comparable levels through persistent rhizodeposition from perennial grasses. Whereas this approach is relatively easy to execute and can serve as a starting point for similar tasks, the selected targets and thresholds are arbitrary and highly sensitive, suggesting they were chosen to align with data availability and specific research objectives.

8. 题目: Distributions of Organic Carbon and Nitrogen in Aggregates of Saline‐Alkaline Soils in the Yellow River Delta
文章编号: N26031009
期刊: Land Degradation & Development
作者: Amar Ali Adam Hamad, Xiujun Wang, Lipeng Wu, Minggang Xu
更新时间: 2026-03-10
摘要: Soil salinity alters aggregate structure, organic matter dynamics, and carbon stabilization; however, its mechanistic effects on carbon‐nitrogen distribution and soil organic matter (SOM) stability remain inconclusive. We hypothesize that salinity‐induced shifts toward microaggregate dominance weaken the physical protection of SOM, increasing SOC lability and promoting C  N decoupling. Soil samples from low‐ and high‐salinity sites were fractionated into aggregates of < 0.25 mm, 0.25–0.5 mm, 0.5–1 mm, 1–2 mm, and > 2 mm, and analyzed for SOC, total nitrogen (TN), soil inorganic carbon (SIC), and water‐extractable fractions of organic carbon (WEOC), organic nitrogen (WEON), and inorganic carbon (WEIC). High salinity shifted aggregate distribution toward microaggregates, with the < 0.25 mm fraction comprising 75%–84% of mass compared with 25%–30% under low salinity, indicating dispersion and reduced structural stability. This breakdown caused depletion of stabilized C and N pools, as SOC declined to 6.7 g kg −1 under high salinity but remained higher, 13.2 g kg −1 in low salinity soils, while TN ranged from 0.5 to 0.6 g kg −1 versus 1.4 g kg −1 , indicating weaker organic matter retention. SIC was enriched in low salinity soils in the 1–0.5 and 0.5–0.25 mm fractions but reduced under high salinity, suggesting diminished carbonate‐mediated stabilization. Elevated WEOC:SOC and WEON:TN ratios in high salinity soils indicated greater SOM solubilization and mobility. The negative relationship between WEOC:SOC and SIC demonstrated that carbonate minerals constrain organic matter desorption. Salinity therefore destabilizes SOM through coupled physical and geochemical pathways, decreasing C  N retention and increasing lability. These mechanisms apply broadly to salt‐affected soils and highlight the need for salinity management to preserve structure and carbon retention.

9. 题目: Impacts of Organic Fertilization on the Mineralization of Mine Spoil Organic Carbon in an Alpine Coalmine Field
文章编号: N26031008
期刊: Land Degradation & Development
作者: Baojun Lin, Wenquan Yang, Shuai Zhao, Qinyao Li, Weiliang Kou, Yanghua Yu, Yangcan Zhang, Xilai Li, Jiancun Kou
更新时间: 2026-03-10
摘要: This study focused on how to ameliorate coal mine spoil in the Muli mining area via different fertilization treatments using commercial organic fertilizer (COF) and semi‐rotted sheep manure (LSM). Further explored in this study were the impacts of two kinds of organic fertilizers on the coal mine spoil through cultivation experiments in the lab. The results showed that fertilization significantly enhanced the release of CO 2 ( p < 0.05) and also enhanced the enzyme activity related to carbon and nitrogen transformation in all treatments. Partial least squares path modeling analysis further revealed that organic fertilizers mainly affected enzyme activity by regulating the bacterial community, thereby affecting the cumulative priming effect (Cum‐PE). This was the primary pathway via which the organic fertilizers regulated PE. In high‐dosage fertilization treatments, the released CO 2 originated mainly from the fertilizers themselves, indicating that microbial metabolic activities preferentially consumed exogenous organic carbon. This metabolic preference slowed the decomposition of the original organic matter in the coal mine spoil, resulting in a negative PE. Fertilization significantly changed the composition of the bacterial community and also affected the distribution of microbial functional groups, which stimulated the microbial functional potential related to carbon and nitrogen metabolism. The activities and structural changes of these functional communities jointly regulated the direction and intensity of PE. This study systematically elucidated the response of soil organic carbon PE and microbial community to fertilization in mining areas, providing solid theoretical evidences for the amelioration of coal mine spoil in the alpine mining area of Muli.

10. 题目: One-Step Waste Biomass-Derived K2FeO4-Biochar for Enhanced PCM Thermal/Photothermal Performance
文章编号: N26031007
期刊: Journal of Environmental Chemical Engineering
作者: Han Chen, Wenwen Guo, Guoneng Li, Youqu Zheng, Junshu Zhou
更新时间: 2026-03-10
摘要: This study developed a one-step K₂FeO₄ activation process to convert pine sawdust waste into graphitized biochar (K₂FeO₄ serving as both activator and catalyst). This biochar was used to fabricate a myristic acid (MA)-based composite phase change material (CPCM). We investigated how it enhances CPCM microstructure, thermal conductivity, and photothermal conversion efficiency. The biochar's structure, enabled by the one-step process, significantly boosted these properties. Results indicate that biochar activated with K₂FeO₄ and KOH exhibits abundant pore structures, large specific surface area, and high pore volume. Notably, K₂FeO₄-activated biochar (1Fe-BC700) achieved a specific surface area of 1893.0 m²/g and a pore volume of 1.191 cm³/g, significantly enhancing its adsorption capacity. Raman spectroscopy indicated that K₂FeO₄ promoted the graphitization of biochar. The CPCM 1Fe-BC700/MA demonstrated excellent shape stability in testing, with a mass loss rate below 0.5%. Moreover, K₂FeO₄ modification substantially enhanced the composite's thermal conductivity, visible light absorption, and photothermal conversion efficiency. The thermal conductivity of 1Fe-BC700/MA reached 0.451 W/(m·K), representing a 34.6% increase over MA, while photothermal conversion efficiency rose to 71.75%. This study demonstrates that K₂FeO₄ modification can simultaneously achieve pore expansion and graphitization of biochar, providing a novel approach for preparing high-performance photothermal conversion PCMs.

11. 题目: Co-application of humic acid and phosphorus fertilizer enhances soil carbon stability and phosphorus availability in coastal saline paddy fields
文章编号: N26031006
期刊: Plant and Soil
作者: Chuanming Ma, Zhaohui Liu, Ben Cheng, Jinkai Han, Lening Zhang, Zeqiang Sun, Shenglin Liu, Shirong Zhang, Xiaodong Ding
更新时间: 2026-03-10
摘要: Aims Soil salinization degrades aggregate structure, diminishes soil organic carbon (SOC), and constrains phosphorus (P) availability, thereby undermining soil fertility and crop productivity. Consequently, strengthening SOC stability, rebuilding aggregates, and improving P bioavailability is essential for the sustainable use of saline–alkaline paddy soils. Methods A field experiment with two factors was arranged, including two P levels (0 and 32.7 kg ha−1 P) and three HA treatments (0, 68 and 135 kg ha−1), to evaluate the effects of the co-application of humic acid (HA) and P fertilizer on SOC storage and P bioavailability in saline alkali paddy soils. Results Under both P levels, compared with HA0, SOC content in HA1 and HA2 was significantly increased, in which it was highest in P1HA2 treatment. Meanwhile, the proportion of large macroaggregates (LMA) was significantly increased with HA addition. In LMA fraction, polysaccharide-like C and aliphatic-C in P1HA2 treatment were 18.6% and 17.6% higher than that in P0HA0. In addition, specific carbon mineralization rate (SCMR) was decreased with HA application. Compared with P0 level, the content of Ca2-P and Ca8-P in P1 level was significantly increased, especially in HA2 treatment. And the highest content of available phosphorous (AP) was also found in P1HA2, which was 14.3% higher than that in HA0. SOC was positively associated with Ca₂-P and Ca₈-P, whereas SCMR was negatively associated with labile P. Conclusion Co-applying HA with P fertilizer strengthened macroaggregate structure and increased labile P, thereby enhancing SOC storage and P bioavailability in saline–alkaline paddy soils.

12. 题目: One-step pyrolysis of pulp and paper mill wastes for Fe0/Fe3O4/Cu0@biochar: A pH - responsive Fenton-like catalyst with switchable ROS pathways and enhanced electron transfer for efficient organic dye degradation
文章编号: N26031005
期刊: Chemical Engineering Journal
作者: Xiyue Xue, Yanpeng Chen, Yuxin Xiao, Saidi Wang, Hongjie Zhang, Jin Wang, Wen-Hui Zhang
更新时间: 2026-03-10
摘要: This study pioneers a sustainable “waste-to-wealth” strategy for fabricating a high-performance, pH-universal Fenton-like catalyst (FeCu₂@BC_T4) through the one-step co-pyrolysis of acid-precipitated black liquor (APBL) and Fenton sludge with a copper precursor. The innovation lies in the precise engineering of a Fe⁰/Fe₃O₄ heterojunction synergistically coupled with Cu⁰ nanoparticles on a functional APBL-derived biochar. By tuning the Cu/Fe mass ratio and pyrolysis time, the phase composition and electron-transfer properties were optimized. The resulting catalyst exhibits exceptional activity and stability across a broad pH range (3–9), achieving >92.3% methylene blue degradation within 60 min, and demonstrates superior removal efficiency toward various cationic dyes (rhodamine B, crystal violet, malachite green) and an anionic dye (methyl orange). Mechanistic investigations reveal a clear pH-governed transition of reactive oxygen species (ROS) pathways: under acidic conditions (pH 3), •OH-dominated homogeneous–heterogeneous catalysis prevails; under neutral conditions, the system shifts to a heterogeneous process driven by synergistic •OH/¹O₂ oxidation. This unique ROS switch is sustained by efficient electron mediation from the biochar matrix, coupled with robust electron supply and transfer enabled by the Fe⁰/Fe₃O₄ heterojunction and FeCu galvanic coupling. This work provides a novel paradigm for converting industrial solid wastes into advanced catalytic materials with a well-elucidated mechanism, effectively overcoming the critical pH limitation of conventional Fenton technologies and showing broad application prospects for organic wastewater remediation.

13. 题目: Mechanisms of microbial fouling alleviation by controlled-release borates in a recirculating cooling-water system via extracellular polymeric substances composition and metabolomics analysis.
文章编号: N26031004
期刊: Journal of Environmental Management
作者: Haiqing Xu, Yuansheng Pei
更新时间: 2026-03-10
摘要: Biofilm accumulation in recirculating cooling-water systems (RCSs) contributes significantly to microbial corrosion and heat transfer impairment. However, traditional chlorine-based bactericides require frequent replenishment for sustained performance and chlorine ions exacerbate pipeline corrosion. This study employs controlled-release borates (CRBs) to ensure continuous boron release and thorough biofilm contact. The release rate of CRBs in the first 10 days was 39.2 mg/(L·d), following zero-order release kinetics. At dosages above 0.4 g-B/L, CRBs reduced total heterotrophic bacteria counts (below 1.0 × 105 CFU/mL) and mitigated corrosion (below 0.075 mm/a). The determination of extracellular polymeric substances (EPS) showed that borates reduced the total EPS content in biofilm by 45.2%-75.2%, particularly protein and polysaccharide, leading to a looser biofilm structure. Aromatic proteins were more sensitive to borates than humic acid-like substances, with preferential disruption of C=O bonds in amide I over aromatic conjugated structures as confirmed by 2D-Fourier transform infrared spectra. Microbial community analysis indicated that borates decreased the abundance of EPS-producing bacteria (e.g., Flavobacterium), antibiotic-resistant bacteria (e.g., Acinetobacter), and corrosion-associated bacteria (e.g., Desulfovibrio). Simultaneously, borates interfered with EPS synthesis by regulating the secretion of endogenous quorum sensing signals. Flow cytometry confirmed that biofilm inhibition stemmed from sustained regulation of microbial physiology by borates rather than acute toxicity. The inactivation of key antioxidant enzymes rendered cells membrane more vulnerable to reactive oxygen species. Metabolomics analysis showed the decreased levels of antioxidative and corrosive metabolites. The CRBs show promise as a viable strategy for biofilm control in RCSs, offering sustained effect without contributing to aquatic eutrophication.

14. 题目: Molecular-Level Insights into the Reshaped Redox Characteristics of Wildfire-Impacted Soil Dissolved Organic Matter: Implications for Pollutant Dynamics.
文章编号: N26031003
期刊: Environmental Research
作者: Junfeng Xiao, Shishu Zhu
更新时间: 2026-03-10
摘要: Global wildfires significantly reshape soil dissolved organic matter (DOM), yet the molecular-level mechanisms governing its redox characteristics and induced pollutant dynamics remain unclear. The study comprehensively deciphered the linkages of molecular diversity in pyrogenic DOM (PyDOM) to the electron-donating capacity (EDC) and electron-accepting capacity (EAC), exploring their role in regulating the generation of hydroxyl radical (•OH) in the dark. By leveraging mediated electrochemical characterization and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the highly heterogeneous molecular compositions across the PyDOMs can be divided into three representative redox groups. Results showed that the EDC pool was closely associated with N-containing aliphatic, polyphenols and highly unsaturated phenolic compounds, with EAC pool being primarily composed of CHO-containing compounds of polyphenols and highly unsaturated phenolic compounds, among which the EAC-related molecules exhibited significantly higher molecular weights (MW) than those driving EDC. Crucially, two distinct molecular organization modes were revealed: the EDC demonstrated a significant shift in contributions from multi-source components across differential MWs, whereas EAC maintains a high structural consistency, reflecting its stable reliance on oxygen-rich aromatic conjugates. Wildfires regulate redox capacity by reshaping the composition and abundance of these characteristic molecular groups, further inducing a significant positive correlation between the EDC and •OH formation potential, which implied the impact of post-wildfire on the long-term pollutant dynamics and biogeochemical cycling. This study establishes a mechanistic linkage of wildfire-reshaped organic carbon pools to their redox traits, offering new insights into assessing post-fire environmental impacts.

15. 题目: The Dual Effects of dissolved Algal Organic Matter (dAOM) on Algal Removal Efficiency using In-situ Flotation: Mechanistic insights into dAOM Protonation and Deprotonation.
文章编号: N26031002
期刊: Environmental Research
作者: Shaozhe Cheng, Jun Hu, Lili Li, Zimin Wang, Jing Li, Haiyang Zhang, Yuying Li, Xuezhi Zhang
更新时间: 2026-03-10
摘要: In-situ flotation using positively charged bubbles is a promising technique for controlling harmful algal blooms (HABs). However, dissolved algal organic matter (dAOM) plays a key role in determining flotation efficiency, often causing significant variability, and its underlying mechanisms remain poorly understood. To address this knowledge gap, this study systematically investigated the effects of dAOM on in-situ flotation efficiency, utilizing a high speed microscopic camera to examine bubble-dAOM-cell interactions at the single-bubble level. The results indicate that dAOM exerts dual effects of either promoting or inhibiting in situ flotation efficiency, with the extent of dAOM protonation and deprotonation serving as the key factor driving these contrasting mechanisms. Under acidic conditions when dAOM was protonated, single bubbles achieved coverage angles of up to 170°, thus promoting enhanced adhesion and the formation of network structures, resulting in flotation efficiencies as high as 91%. Conversely, under alkaline conditions when dAOM was deprotonated, coverage angles decreased to 66° due to electrostatic repulsion, leading to reduced adhesion and flotation efficiency as low as 47%. The degree of protonation of dAOM surface functional groups in the raw samples was positively correlated with flotation efficiency at a modifier concentration of 25 mg L-1 Al3+, highlighting the pivotal role of surface functional groups in influencing flotation performance. This study provides novel insights into HAB control using in-situ flotation by elucidating the effects of dAOM protonation on the adhesion performance of algal cells to individual bubbles.

16. 题目: Integrating Iron-Magnesium Modified Biochar and Shewanella Putrefaciens 4H for Synergistic Dye Removal from Water: Insights into Adsorption and Biodegradation Mechanisms
文章编号: N26031001
期刊: Water, Air, & Soil Pollution
作者: Xi Chen, Jianwei Yang, Jialiang Yu, Shuhong Zhou, Muhammad Shaaban, Nermin Ali, Qi-an Peng, Yajun Cai
更新时间: 2026-03-10
摘要: Iron-magnesium modified biochar (FeMgBC) was synthesized using bioleach and physical impregnation methods. The removal efficiencies for three typical dyes were as follows: the adsorption capacities for malachite green (MG), reactive brilliant red (RBR), and methylene blue (MB) increased by 34.81-, 23.81-, and 24.76fold, respectively, compared with the unmodified biochar. After five adsorption–desorption cycles, the removal rate of RBR decreased by 23.84%, while those of MB and MG decreased by 7.89% and 4.84% respectively, demonstrating the reusability and stability of FeMgBC. The study demonstrated that the adsorption of MB and MG by FeMgBC was primarily governed by physical adsorption accompanied by partial chemical interactions, whereas the adsorption of RBR was mainly controlled by chemical adsorption. Density functional theory (DFT) calculations revealed that the adsorption energy of the Fe/Mg active site for RBR (-8.03/-8.34 eV) was much higher than that of MB (-0.44/-0.47 eV) and MG (-0.51/-0.48 eV) (p < 0.05), and electron transfer efficiency was further confirmed through electron structure analysis, verifying the distinct adsorption mechanisms among the dyes. In addition, when FeMgBC was combined with Shewanella putrefaciens 4H, the removal efficiency of RBR dye was 59.11% higher than that achieved by Shewanella putrefaciens 4H alone. The addition of FeMgBC promoted the expression of the azo reductase gene (AzoR) gene in 4H, thereby increasing AzoR enzyme activity and accelerating the cleavage of the azo bond (-N = N-) in RBR. Finally, most of the intermediate products were completely mineralized into CO2 and H2O.

17. 题目: Mineral associated organic matter fractions have an outsized role in nitrogen mineralization and denitrification
文章编号: N26030918
期刊: Geoderma
作者: Andrew J Curtright, Cole Smith, William R Horwath, Xia Zhu-Barker
更新时间: 2026-03-09
摘要: The mineral-associated (MAOM) and particulate (POM) fractions of soil organic matter demonstrate distinct dynamics and biochemical properties, but it is unknown how these fractions contribute to soil fertility and respond to soil health management practices, such as compost application. Given their distinct physical and biochemical characteristics, these fractions contain differing amounts of potentially mineralizable nitrogen (N). In this study, we aimed to determine N flux from MAOM and POM fractions. Following a growth chamber study where soils of two different textures were treated with 15N-labeled urea fertilizer, with or without compost, the soils were fractionated into MAOM and POM and added back to their respective original soils as a substrate-addition experiment. Throughout the 52-day incubation, net N mineralization was assessed, and nitrous oxide (N2O) flux and CO2 production were measured using cavity ring down spectroscopy. In addition, we performed denitrification assays to assess the contribution of each fraction to denitrification under anaerobic conditions. We found that the MAOM addition increased N2O production in the denitrification assays and during the incubation with the sandy soils. Across both soils, more N was mineralized from MAOM than from POM. Compost-application history reduced the rate of N mineralization from MAOM and decreased N2O production throughout the incubation in the sandy soils. Our study demonstrates that isolated MAOM-sized fractions were an active source of N in these incubated soils, and that the specific N-cycling dynamics of MAOM and POM can vary considerably depending on soil texture and management history, such as prior compost application.

18. 题目: Anecic earthworms and residue management synergistically enhance soil carbon sequestration via macroaggregate formation
文章编号: N26030917
期刊: Geoderma
作者: Guobing Wang, Qian Zhang, Yuchen Gu, Xiaoming Zou, Han Y H Chen, Honghua Ruan
更新时间: 2026-03-09
摘要: Soil organic carbon (SOC) sequestration is critical for climate change mitigation. Anecic earthworms, as key ecosystem engineers, are hypothesized to promote SOC storage by forming stable soil aggregates, but their interaction with plant residue inputs remains unclear. To address this knowledge gap, we conducted a one-year field experiment in a poplar plantation to investigate the individual and combined effects of earthworm inoculation (Metaphire guillelmi) and poplar leaf residue addition (surface mulching vs. soil incorporation) on SOC dynamics. Compared to the control, residue incorporation and earthworm inoculation alone increased the proportion of large macroaggregates (>2000 μm) by 23.3% and 37.9%, respectively. However, their combination yielded a significant synergistic effect, increasing large macroaggregates by 67.4%. Notably, earthworms alone did not increase SOC concentration within aggregates and marginally reduced whole-soil SOC (≈ 0.46%), whereas their combination with residue addition, either mixed into soil or placed on the soil surface, significantly boosted SOC in large macroaggregates and raised whole-soil SOC by up to 21.7%. Structural equation modeling confirmed that residue addition directly enhanced SOC pools, whereas earthworms acted primarily by promoting soil large macroaggregates formation and increasing aggregate stability (quantified by mean weight diameter). This synergistic interaction resolves the “earthworm dilemma” by offsetting short-term carbon mineralization through long-term SOC protection in stable aggregates. We conclude that anecic earthworms (e.g., Metaphire guillelmi) act as critical regulators of soil physical structure, and their contribution to soil organic carbon sequestration efficiency depends critically on their interaction with fresh plant residue inputs. Our findings provide actionable insights for climate-smart forestry, highlighting that integrating earthworm conservation with optimized residue management is a key strategy to strengthen terrestrial carbon sinks in forest plantations.

19. 题目: Hyperspectral-based dynamic monitoring of soil organic matter in saline-alkali soils
文章编号: N26030916
期刊: Journal of Soils and Sediments
作者: Kezhu Tan, Weiqi Sun, Zonghui Zhuo, Hao Gan, Wenyan Guo, Xihai Zhang
更新时间: 2026-03-09
摘要: Purpose The northeast black soil region is an important area for grain production, but soil salinization and degradation seriously threaten the sustainability of agriculture. Returning decomposed straw to the field can effectively improve the fertility of saline‑alkali soil, but there are still deficiencies in the dynamic monitoring of soil quality after straw return. In this study, a hyperspectral machine learning framework was developed to dynamically monitor the soil organic matter (SOM) content in the modified soil. Materials and methods Firstly, 900 samples were collected from the improved saline‑alkali field planted with soybean, and the hyperspectral data of 203 bands and the organic matter content measured in the laboratory were collected simultaneously. Then a combined preprocessing strategy of multiplicative scatter correction (MSC) and standard normal variate (SNV) transformations was employed to suppress spectral interference from salinity and alkalinity. A dynamic prediction model was constructed by integrating principal component analysis (PCA) with sparrow search algorithm (SSA)‑optimized support vector regression (SVR). Results and discussion Results showed that the PCA-SVR model achieved the best performance, with a determination coefficient (R²) of 0.8381 and a mean squared error (MSE) of 0.1619 on the test set, representing a 19.3% improvement in R²over the partial least squares regression (PLSR) models. SOM content followed a “steady growth—temporary decline—significant accumulation” pattern during soybean development, reaching a maximum of 35.40 g/kg at maturity. A brief decline occurred during grain filling, likely due to intensified microbial decomposition. Conclusions This study provides high-resolution spectral data and a machine learning framework for evaluating saline-alkali soil remediation across multiple growth stages. These results offer practical guidance for improving the sustainability of saline-alkali farmland.

20. 题目: Enhanced abiotic removal of soil monoaromatic hydrocarbons by biochar addition
文章编号: N26030915
期刊: Journal of Soils and Sediments
作者: Huaiyu Ge, Bing Hong, Hao Zhang, Tianyu Hu, Jian Kang, Yinuo Wang, Jingyi Wang, Xiaoya Zheng, Hua Fang, Shutan Ma, Juan Zhao, Ting Wu
更新时间: 2026-03-09
摘要: Purpose Soil contamination by typical monoaromatic hydrocarbons such as benzene and toluene (BT) poses severe environmental and health risks, prompting the need for eco-friendly remediation strategies using biochar. Its abiotic removal efficacy for BT was systematically investigated here to identify the contributions of adsorption and chemical degradation, evaluate the impacts of various factors on adsorption efficacy, and clarify adsorption mechanisms. Methods Biochar was produced at pyrolysis temperatures of 400, 500, and 600 °C. Controlled experiments in sterilized soil, with and without biochar amendment, were conducted to quantify its contribution to abiotic BT removal, together with adsorption and chemical degradation experiments. Adsorption isotherms were evaluated across different pyrolysis temperatures, biochar addition amounts (2–6% w/w), and equilibrium temperatures (15–35 °C), alongside kinetic and desorption studies, to comprehensively investigate BT removal mechanisms in biochar-amended soils. Results The addition of 1% biochar enhanced abiotic removal of benzene and toluene by 33.8% and 38.8%, respectively, with adsorption identified as the dominant mechanism. Biochar exhibited a stronger affinity for benzene, attributed to its greater hydrophobicity and preferential interaction with hydrophobic surfaces. Optimal adsorption occurred under conditions of 500 °C pyrolysis temperature, 4% biochar addition, and 25 °C equilibrium temperature. Freundlich isotherm modeling and Gibbs free energy values confirmed a multilayer physisorption process driven by heterogeneous interactions, including hydrophobic site selectivity, π-π electron donor-acceptor bonding, and electrostatic forces, with minimal contributions from pore-filling or monolayer adsorption. Adsorption kinetics were best described by the pseudo-second-order model. Desorption experiments further demonstrated the effectiveness and stability of biochar (particularly 500 °C) as an adsorbent. Conclusion This study bridges critical gaps by comparing variable-specific adsorption differences, validating biochar’s superiority over pure soil, and providing mechanistic insights into surface-driven physisorption, offering actionable guidelines for optimizing biochar-based remediation of volatile organic compounds (VOCs)-contaminated soils through parameter optimization aligned with contaminant properties and environmental conditions.