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281. 题目: Reshaping bio-nano interfaces via dissolved humic substances: Metabolic priming and electron shuttling drive robust Cr(VI) detoxification by MR-1/nZVI
文章编号: N26082009
期刊: Journal of Hazardous Materials
作者: Xiangru Zuo, Shaohua Chen, Ziqi Zou, Yihang Sun, Hui Wu, Ling Xiong, Hengpeng Ye, Dongyun Du
更新时间: 2026-08-20
摘要: The application of nanoscale zero-valent iron (nZVI) and dissimilatory iron-reducing bacteria for environmental remediation is restricted by nZVI passivation and reactive oxygen species (ROS)-induced bacterial inactivation. To address these challenges, a dual-enhancement strategy using natural dissolved humic substances (DHS) was developed, integrating metabolic priming and electron shuttling to establish a highly active MR-120/nZVI/DHS system. Under optimal conditions, this system completely eliminated 80 mg/L Cr(VI) within 48 h, demonstrating a 2.94-fold increase in the apparent reduction rate constant (kobs) versus the traditional MR-1/nZVI system. Mechanistically, DHS-induced metabolic priming stimulates substantial extracellular polymeric substances (EPS) secretion. EPS and exogenous DHS form an electroactive microlayer that physically shields cells from nanoparticles and Cr(VI) toxicity, and directly quenches extracellular hydroxyl radicals (·OH). Meanwhile, metabolic priming pre-activates intracellular antioxidant defense and enhances ROS scavenging, alleviating nZVI/Cr(VI) combined toxicity and greatly improving bacterial survival. Benefiting from the protective microenvironment, intracellular energy (ATP) and reductive power (NADH) levels enhanced by 1.74- and 2.78-fold, respectively. These surges triggered 8.88- and 48.64-fold upregulation of outer membrane cytochrome c (Cyt c) and endogenous riboflavin (RF), effectively activating a dual-channel electron transfer network and driving a 15.71-fold surge in overall electron transport system activity (ETSA). The enhanced electron flux accelerates dissolution of the nZVI surfaces passivation layer, continuously regenerating active biogenic Fe(II) to reduce Cr(VI) and drive its co-precipitation into stable FeCr2O4 spinels. This work presents an efficient approach for treatment of Cr(VI)-contaminated wastewater and offers new theoretical insights into synergistic detoxification at the bio-nanomaterial interface under heavy metal stress.

282. 题目: Pinewood engineered biochar as a solution to nutrient leaching management: Mitigating phosphorus and nitrate loss from poultry litter under saturated porous conditions
文章编号: N26082008
期刊: Journal of Environmental Management
作者: Atiqur Rahman, Rakesh Kumar, Gurparshad Singh Brar, Jasmeet Lamba, Sushil Adhikari, Nitesh Kumar Kasera, Henry Allen Torbert, Dexter Watts, Thomas R Way
更新时间: 2026-08-20
摘要: Poultry litter (PL) is a valuable, inexpensive source of phosphorus (P) and nitrogen (N). However, repeated PL applications to soils cause P stratification and enhance both phosphate ( ) and nitrate-N ( ) losses through surface runoff and leaching, which can result in the contamination of surface and groundwater. Therefore, this study evaluated pristine biochar (PBC), iron-modified biochar (Fe-PBC), and magnesium-modified biochar (Mg-PBC) for immobilizing and extracted from PL using column and batch experiments. Column experiments demonstrated early breakthroughs in PBC and Fe-PBC, indicating limited immobilization, whereas Fe-PBC substantially immobilized , and Mg-PBC effectively immobilized both and . Magnesium-modified biochar exhibited experimental maximum adsorption capacity ( of (1.25 ± 0.003 ) while was nearly identical for both Mg-PBC (0.1 ± 0.001 ) and Fe-PBC (0.09 ± 0.0003 ). Phosphate adsorption kinetics on PBC and Fe-PBC were best described by Elovich model, whereas adsorption kinetics were better explained by the pseudo-first-order, pseudo-second-order, and Elovich models. The Sips isotherm best fits for adsorption on PBC and Mg-PBC, along with adsorption on all biochars, indicating heterogeneous multilayer adsorption. Langmuir fits described adsorption well, but poorly described adsorption, whereas the Freundlich model better reflected the heterogeneous adsorption. Results suggest that Fe-PBC can serve as adsorbent, while Mg-PBC can act as an effective adsorbent for both and , suggesting potential solutions for nutrient management. This study helped understand biochar-nutrient interactions under chemically complex PL-solutions and provides insights for developing sustainable nutrient management strategies in manure-applied regions.

283. 题目: Biodegradation-driven reconfiguration of sediment dissolved organic matter controls pollutant-specific binding pathways of lead and tetracycline at the sediment–water interface
文章编号: N26082007
期刊: Journal of Hazardous Materials
作者: Haoyu Ren, Lan Zhang, Xin Yao, Hongwei Du, Zongyao Zhang, Huaiyang Fang, Kun Wang
更新时间: 2026-08-20
摘要: Sediment dissolved organic matter (SDOM) is a dynamic mediator of contaminant fate in lake sediments, yet how its biodegradation-driven reorganization alters pollutant binding under regional heterogeneity remains unresolved. Here, we examined lead (Pb) and tetracycline (TC) binding to SDOM from 18 sites across three environmentally distinct zones of Lake Nansi, a hydro-regulated shallow lake, before and after a 28-day biodegradation experiment. Before biodegradation, the upper lake area contained more protein-enriched SDOM, with the relative contribution of the protein-like component C3 averaging 52.0%, compared with 38.2% and 41.8% in the near-dam and lower lake areas, respectively. Biodegradation reduced C3 by 47.2%, increased the humification index by 17.2%, and decreased total fluorescence intensity by 30.8%, indicating substantial restructuring of SDOM composition and microbial assemblages. This restructuring produced pollutant-specific responses. Pb showed stronger regional heterogeneity than TC in both binding sequence and apparent binding response, and its dominant binding contribution shifted away from the protein-like fraction after biodegradation. TC displayed a more conserved binding sequence but became increasingly associated with transformed fulvic-like fractions after biodegradation. Piecewise structural equation modeling further revealed distinct association pathways: Pb apparent binding response was mainly associated with the regional environmental gradient (β = 0.364, p = 0.034), whereas TC apparent binding response was more closely linked to C3 (β = 0.702, p < 0.001) and biodegradation (β = 0.498, p = 0.012). These findings demonstrate that biodegradation-driven SDOM reorganization creates distinct binding pathways for metals and antibiotics, and highlight the importance of incorporating SDOM quality, microbial reorganization, and spatial heterogeneity into process-based assessment of contaminant fate in regulated lake systems.

284. 题目: China’s lakes remain carbon sources: Insights from the balance between intrinsic carbon sequestration and emissions
文章编号: N26082006
期刊: Science Advances
作者: Shilan Wang, Xiaodong Nie, Yi Wang, Ying Zhao, Josep Peñuelas, Alexander Gelfan, Zhengang Wang, Peng Gao, Di Tong, Zhongwu Li
更新时间: 2026-08-20
摘要: Accurate assessments of lake carbon balance are essential for filling gaps in the global carbon budget and addressing climate change. However, persistent uncertainties arise from an incomplete understanding of intrinsic carbon sequestration and its balance with emission effects. Here, using source fingerprinting techniques, we isolated the autochthonous organic carbon (OC Auto ) burial, which represents the intrinsic carbon sequestration of lakes. We found that OC Auto burial accounted for only 53.23% of total lake carbon emissions in the 2020s, leaving China’s lakes as carbon sources (−0.83 teragrams of carbon per year). Regionally, lakes on the Qinghai-Tibet and Yunnan-Guizhou Plateaus have shifted to carbon sinks, whereas lakes in the eastern and northeastern regions remain major carbon sources. Scenario projections indicated that restoring China’s lakes to macrophyte-dominated states under the Shared Socioeconomic Pathway SSP2-4.5 scenario could transition them into stable carbon sinks before OC Auto burial peaks around 2070. To facilitate this transition, we proposed a lake classification-and-management framework based on carbon sink potential and emission risks to guide carbon sequestration and climate mitigation efforts.

285. 题目: A Microfluidic Multispectral Diffraction Platform for Quantitative Analysis of Atmospheric Black Carbon Aerosols
文章编号: N26082005
期刊: Analytical Chemistry
作者: Zhaoyuan Zhang, Tongge Li, Haodong Liu, Ni Yu, Wenguang Wu, Chao Feng, Minghua Li, Si Chen, Ning Yang
更新时间: 2026-08-20
摘要: Atmospheric black carbon aerosol (BC) is a major environmental pollutant that contributes to climate warming and threatens respiratory and cardiovascular health, making its accurate quantification essential for coordinated pollution control. However, BC is mainly submicron in size and commonly mixed with multicomponent impurities, leading to complex optical coupling effects that hinder precise quantification. In addition, conventional instruments are often expensive and bulky, limiting their suitability for rapid on-site detection and high-density deployment. Here, we present a precise BC quantification system that integrates a microfluidic chip with multispectral diffraction imaging. First, a microfluidic chip integrating inertial separation, low-velocity sheath-flow regulation, and high-voltage electrostatic capture was used to remove interfering particles and uniformly enrich submicron BC particles within the imaging region. Subsequently, a lensless diffraction imaging system was developed to acquire hyperspectral diffraction fingerprints of aerosol particles over the wavelength range of 400–800 nm. These fingerprints not only enabled BC to be discriminated from similarly sized interfering particles, including microplastics and pathogenic spores, but also provided discriminative multispectral diffraction features for quantitative analysis. Finally, the selected spatial–spectral features were input into the BC-GCM model to establish a mapping between the multispectral diffraction responses and BC concentration. The system achieved a maximum enrichment efficiency of 92%. Over a concentration range of 0.01–0.20 mg/m3, the model yielded an R2 of 0.98 and an average test-set recognition accuracy of 84%. Owing to its compact structure and low cost, this platform shows strong potential for rapid on-site response and high-density BC monitoring in complex atmospheric environments.

286. 题目: Ammonium Enrichment Reveals Microbial Processing of Deep-Sea Dissolved Organic Carbon
文章编号: N26082004
期刊: Environmental Science & Technology
作者: Guodong Sun, Lingli Qiu, Peng Zhang, Yihui Guo, Chen He, Quan Shi, Wei Xie
更新时间: 2026-08-20
摘要: Ammonium availability may alter microbial access to persistent dissolved organic matter (DOM), but the response capacity of indigenous deep-water microbial communities remains poorly constrained. We used dark microcosms established with South China Sea seawater from 500 and 2000 m to examine microbial and DOM responses to ammonium enrichment. Microcosms received 50 μM ammonium nitrogen (NH4+–N) and were incubated without agitation at 24 °C for 90 days alongside unamended controls. Nutrient and dissolved organic carbon (DOC) measurements were integrated with optical DOM characterization, 16S rRNA gene profiling, and semiquantitative molecular formula profiling by Fourier transform ion cyclotron resonance mass spectrometry. Ammonium-amended microcosms showed 46–50 μM net NH4+–N depletion, accumulation of oxidized nitrogen, and numerically greater 90-day DOC loss than controls (11–12 vs 5–6 μM), although DOC trajectories did not differ significantly between treatments. These changes coincided with increased relative representation of Thaumarchaeota and Bacteroidetes, stronger tyrosine-like and tryptophan-like fluorescence signals, and pronounced shifts in detectable molecular formula composition. Collectively, these coordinated responses reveal latent DOM-processing capacity in indigenous deep-water communities and are consistent with an ammonium-associated priming-like response potentially involving ammonia oxidation and autotroph–heterotroph coupling.

287. 题目: Microbial Reduction–Induced Selective DOM Transformation Governs As(III) Oxidation under Redox Oscillations
文章编号: N26082003
期刊: Environmental Science & Technology
作者: Xiangjun Meng, Jialin Chi, Mengmeng Yin, Shiyin Wu, Kai Liu, Xin Zhang, Kai Jiang, Christine V Putnis, Xiaoxia Zhou, Liping Fang, Fangbai Li
更新时间: 2026-08-20
摘要: Microbial respiration-triggered reductive transformation of dissolved organic matter (DOM) plays a central role in O2 activation and, consequently, As(III) oxidation under fluctuating hydrological conditions. However, the key DOM components and their molecular transformations associated with this electron-transfer process remain poorly resolved. Here, by integrating Fourier transform ion cyclotron resonance mass spectrometry with machine learning, we reveal that fulvic acid (FA), the predominant DOM fraction, undergoes selective molecular transformation by Geobacter sulfurreducens PCA, forming a reactive subpool that drives O2 activation and thereby enhances As(III) oxidation by approximately 2–10 fold. Reaction network analysis reveals that oxygen-rich aromatic precursors are preferentially transformed into more reduced intermediates through decarboxylation, dehydrogenation, and partial reduction pathways. These transformations collectively shift the molecular composition toward lower oxidation states and enhanced redox reactivity. Machine-learning analysis further identifies nitrogen- and sulfur-containing molecules with low oxidation states as the key components governing the overall redox activity of the system. These species represent a functionally distinct fraction of microbially transformed FA with enhanced electron-donating capacity. This study provides molecular-level insights into how microbial DOM transformation regulates O2 activation and As(III) oxidation, offering a mechanistic basis for predicting and manipulating redox reactivity in dynamic soil and sediment systems.

288. 题目: The organic phosphorus economy of tropical rain forests along a phosphorus-use efficiency gradient in Borneo
文章编号: N26082002
期刊: Plant and Soil
作者: Kanehiro Kitayama, Daiki Yokoyama, Taiki Mori, Kei-ichi Okada, Benjamin L Turner
更新时间: 2026-08-20
摘要: Background and aims Phosphorus (P) cycling regulates the nutrition and ecology of tropical forests, yet there is considerable uncertainty about the forms and fluxes of P in these ecosystems. In particular, the contribution of organic P remains uncertain, despite being fundamental to understanding forest ecology. Biological P pools in tropical forests turn over rapidly, so the flux of organic P through them represents the total mineralization rate of organic P assuming a constant pool size under a short-term steady state condition. Methods We quantified organic and inorganic P fluxes through three biological compartments (fine litter, fine roots, and soil microbial biomass) in tropical forests of Borneo spanning a strong gradient of P availability and limitation. We used this data in a short-term steady state P budget model to identify an organic P economy of lowland tropical forests. Results Organic P accounted for 86 to 92% of the total biological P flux, with greater values in P rich sites. Most of the P flux originated from organic P turnover through the microbial biomass. The proportion of organic P in the microbial biomass explained the variation in the relative contribution of organic P to total biological P flux. Conclusion Rapid microbial turnover and the large proportion of microbial P in organic forms means that organic P is the predominant form of P supply in tropical forests. Organic P dynamics and acquisition therefore drive P nutrition and mechanisms of adaptation to P deficiency in these productive and hyperdiverse ecosystems.

289. 题目: Soil-dependent short-term transfer of fertilizer nitrogen into microbial biomass and mineral-associated organic matter
文章编号: N26082001
期刊: Geoderma
作者: Manjot Kaur Rekhi, Amanda B Daly, Brian B McSpadden Gardener, Serita D Frey, Lee Hildebrand, Marty R Schmer, A Stuart Grandy
更新时间: 2026-08-20
摘要: Starter nitrogen (N) fertilizer is commonly applied to agricultural soils in the U.S. Midwest in the spring, at or near planting, when crop demand is low. This timing increases the risk of environmental N loss and inefficiencies in fertilizer use before substantial crop uptake begins. Here, we tested a potential mechanism for retention of this fertilizer N: microbial N interception and accumulation within mineral-associated organic matter (MAOM). We also tested how strongly this pathway depends on soil type and microbial properties. We conducted an incubation with two contrasting agricultural soils amended with 15N-labeled urea ammonium nitrate (UAN) fertilizer, a biostimulant-containing starter fertilizer (InFurrow), or their combination at low and high rates, and quantified fertilizer-derived N in total dissolved N (TDN), microbial biomass N (MBN), and MAOM at 14 and 48 days. Despite the absence of plants, fertilizer N moved quickly into microbial and MAOM pools. MBN recovered ∼ 2–19 % of applied 15N, and fertilizer N comprised 30–90 % of MBN by day 14 and 50–100 % by day 48. Recovery in MAOM at day 14 ranged from ∼ 5–12 % in sandy loam soils and ∼ 20–30 % in silty clay loam soils, reaching up to 32 %. Fertilizer-derived MBN was moderately related to fertilizer-derived MAOM-N (R2 = 0.31–0.68), and an elevated qCO2 (metabolic quotient) under high-rate UAN further suggests microbial physiology helped regulate the conversion of added N into organic pools. Our results show that microbial fertilizer N uptake is rapid (within 14 days) and, together with incorporation into MAOM, can move fertilizer N from inorganic to organic pools. This pathway may reduce its vulnerability to loss in the short-term, but future studies are needed to determine whether this retained N in MAOM later becomes available for crop uptake.

290. 题目: Mechanisms of Natural Organic Matter Influencing on Coagulation Process for Nanoplastics Removal from Water
文章编号: N26081919
期刊: Water, Air, & Soil Pollution
作者: Cuimin Feng, Tingting Liang, Yue Xing, Ziyu Guo, Zhuo Chen
更新时间: 2026-08-19
摘要: Nanoplastics pose potential risks to drinking-water safety. In this study, 50 nm polystyrene nanoplastics (PSNPs) were selected as the target pollutant, and polyaluminum chloride (PAC) combined with anionic polyacrylamide (PAM) was used for coagulation. The process parameters were optimized using response surface methodology, and the optimal conditions were a PAC dosage of 5.5 mg/L, a PAM dosage of 1.4 mg/L, and pH 7.5, under which the PSNPs removal efficiency reached 94.2%. Under these optimized conditions, the inhibitory effects and mechanisms of three representative natural organic matter (NOM) components—humic acid (HA), bovine serum albumin (BSA), and sodium alginate (SA)—were systematically investigated. All three NOM components inhibited PSNPs removal in a concentration-dependent manner. Combined FTIR, XPS, and 2D-COS analyses showed that HA (0.5–2.0 mg/L) reduced PSNP removal by up to 16.45 percentage points mainly through π–π interactions and hydrogen bonding, resulting in binding-site masking. BSA (5–15 mg/L) caused the strongest inhibition, reducing PSNP removal by up to 28.06 percentage points, probably through hydrophobic adsorption and formation of a protein layer that induced steric hindrance. SA (0.2–0.8 mg/L) caused moderate inhibition, decreasing PSNPs removal by 1.5–11.9 percentage points by introducing additional negative charges through carboxyl groups and enhancing electrostatic stabilization. These results indicate that different NOM components interfere with PSNPs coagulation through distinct pathways, including binding-site masking, physical blocking, electrostatic stabilization, and potential competition for coagulants.

291. 题目: Ball-milled magnetic biochar for efficient activation of hydrogen peroxide to remove norfloxacin: Performance and mechanism
文章编号: N26081918
期刊: Journal of Environmental Chemical Engineering
作者: Tushan Zhong, Yue Fu, Yingyi Chen, Yunqiang Yi, Weirui Chen, Zenghui Diao
更新时间: 2026-08-19
摘要: Magnetic biochar (MBC) can activate H2O2 to produce reactive oxygen species for removing antibiotics from water, but its activation efficiency needs to be further improved. Herein, ball-milled magnetic biochar (BMBC) derived from banana peel was prepared via impregnation–pyrolysis followed by ball milling, and its performance for activating H2O2 to degrade norfloxacin (NOR) was evaluated. Ball milling treatment increased the specific surface area of MBC from 137.76 m2·g−1 to 334.61 m2·g−1 and enriched surface functional groups of MBC including Cdouble bondO, Fe-O, pyridinic-N, and pyrrolic-N groups. The BMBC/H2O2 system achieved 95.67% NOR removal efficiency with a rate constant of 1.70 × 10−2 min−1, which was approximately 1.98 times higher than that of pristine MBC/H2O2 in removal efficiency and 10.37 times higher in rate constant. Electron paramagnetic resonance (EPR) and radical quenching experiments confirmed that ·OH was the primary reactive species responsible for NOR removal in the BMBC/H2O2 system, with ·O2- playing a secondary role. Mechanistic analysis revealed that the Fe(II)/Fe(III) cycle in BMBC serves as the core driver for H2O2 activation, while Cdouble bondO and pyridinic-N act as electron donors, and graphitic carbon facilitates electron shuttling, collectively contributing to H2O2 activation. Liquid chromatography-mass spectrometry (LC-MS) identified NOR degradation via piperazine ring opening, decarboxylation, and deamination. The BMBC/H2O2 system maintained NOR removal efficiency exceeding 87.60% in real water matrices, indicating robust anti-interference capability. Overall, ball milling offers a facile and effective strategy to enhance the catalytic performance of magnetic biochar for the oxidative removal of fluoroquinolone antibiotics from water.

292. 题目: Enhancing dark fermentative hydrogen production from food waste by oxidized biochar and sulfidated nanoscale zero-valent iron
文章编号: N26081917
期刊: Journal of Environmental Chemical Engineering
作者: Shiyan Gu, Haiqiao Zhao, Ruoyu Kuang, Haiyang Xu, Xinyi Yu, Jiaxin Guo, Min Zhang
更新时间: 2026-08-19
摘要: This study demonstrates that co-applying hydrogen peroxide–modified biochar (O-BC) and sulfidated nanoscale zero-valent iron (S-nZVI) greatly enhances hydrogen production from dark fermentation of food waste. O-BC provides a porous, oxygen-rich surface, while S-nZVI maintains Fe(0) with surface iron sulfides to improve stability and redox activity. In single-factor tests, the optimal S-nZVI and O-BC dosages were 200 mg L−1 and 15 g L−1, increasing hydrogen production by 43.2% and 21.36% respectively. When used together, the combination yielded 2571.67 mL of cumulative H2 （59.26 mL H₂ g⁻¹ VS）, a 77.19% rise over the control, with higher hydrogenase activity and a shift toward butyrate-type fermentation, indicating improved fermentation stability. Response surface methodology identified optimal conditions: O-BC 17.59 g L−1, S-nZVI 237.73 mg L−1, and initial pH 6.70. Predictions agreed with validation results, confirming model reliability. Overall, the O-BC and S-nZVI co-application enhances hydrogen production by promoting microbial colonization, facilitating electron transfer, and stabilizing the fermentation microenvironment, offering practical guidance for scalable waste-to-hydrogen processes.

293. 题目: Algal-Bacterial Biofilm Reactors for Petrochemical Wastewater: Matrix-Dependent DOM Transformation and Stage-Specific Applicability
文章编号: N26081916
期刊: Environmental Research
作者: Yueying Liu, Yuan Lin, Sijia Ma, Juntao Shu, Hongqiang Ren, Ke Xu
更新时间: 2026-08-19
摘要: Petrochemical wastewater (PCW) treatment remains challenging because residual dissolved organic matter (DOM) after conventional treatment still contains complex, refractory, and heteroatom-rich molecular components. Algal-bacterial biofilm (AB) systems have potential for both secondary and advanced treatment; however, their stage-dependent applicability within PCW treatment trains remains unclear. In this study, three AB reactors were fed with dissolved air flotation effluent (DAFE), secondary biological treatment effluent (SBTE), and effluent from a high-activity sludge carbon-capture reactor (ASCE). The three wastewater matrices resulted in distinct patterns of treatment performance, DOM transformation, and biofilm response. After PCW feeding began, all reactors showed short-term inhibition followed by gradual recovery, with the SBTE-fed reactor showing comparatively higher total nitrogen and total phosphorus removal after recovery. Excitation-emission matrix fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry further showed that the SBTE-fed reactor achieved greater attenuation of fluorescent DOM, a decrease in molecular diversity, reduced DOM unsaturation, and removal of nitrogen- and sulfur-containing molecular components. In contrast, low-unsaturation formulas were preferentially removed in the DAFE-fed reactor, whereas the ASCE-fed AB reactor produced more extracellular polymeric substances and soluble microbial products and exhibited stronger antioxidant responses but showed limited DOM attenuation. Microbial community and metatranscriptomic analyses indicated that the SBTE-fed reactor was characterized by functional assemblages and expression patterns related to organic matter transformation, aromatic degradation, energy metabolism, and nitrogen/sulfur transformation. These results suggest that AB reactors may be more suitable as an advanced treatment step following conventional biological treatment in PCW treatment trains.

294. 题目: Ferrous iron-induced secondary mineral formation regulates organic carbon bioavailability and methane recovery from iron-enhanced primary sludge
文章编号: N26081915
期刊: Bioresource Technology
作者: Feifei Chu, Fangmei Cheng, Xiaomeng Zhang, Liyan Wei, Xinhou Zhang, Yun Chen, Lei Zhao, Fei Yang, Nan Shen
更新时间: 2026-08-19
摘要: Iron salt-based chemically enhanced primary treatment effectively captures organic carbon from municipal wastewater, providing a concentrated substrate for methane recovery through anaerobic digestion. However, methane production from iron salt-based chemically enhanced primary sedimentation (Fe-CEPS) sludge remains substantially lower than expected, and the mechanisms responsible for this reduction remain poorly understood. Here, the relationship between iron-bound organic carbon (Fe-OC) formation and methane production was investigated by combining anaerobic digestion experiments with iron mineral-glucose model systems. Increasing Fe dosage reduced methane yield from 221.1 to 74.7 mL CH4 g−1 VS while promoting Fe-OC accumulation. A strong negative correlation was observed between Fe-OC content and methane production. Fresh Fe-CEPS sludge contained only limited Fe-OC (<10% of total organic carbon), whereas Fe-OC accounted for approximately 26% of total organic carbon after anaerobic digestion, indicating that Fe-OC formed predominantly during digestion rather than during coagulation. Iron speciation analyses revealed extensive Fe(III) reduction accompanied by secondary iron mineral formation. Model experiments further demonstrated that Fe(II)-induced mineral transformation increased mineral crystallinity, enhanced organic carbon stabilization, reduced carbon bioavailability, and consequently suppressed methane production. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy further revealed progressively stronger spatial associations between organic carbon and iron minerals as mineral crystallinity increased. These findings reveal a previously unrecognized mechanism whereby Fe(II)-induced secondary iron mineral formation promotes Fe-OC accumulation and reduces organic carbon bioavailability during anaerobic digestion. Regulating iron mineral transformation may therefore represent an effective strategy for improving methane recovery from iron-enhanced primary sludge.

295. 题目: Digital mapping of soil organic carbon using machine learning: A framework for state-level carbon-smart land management
文章编号: N26081914
期刊: Soil and Tillage Research
作者: Pravash Chandra Moharana, Mahaveer Nogiya, Brijesh Yadav, Roshan Lal Meena, Abhishek Jangir, Lal Chand Malav, Sunil Kumar, Ram Prasad Sharma, Ram Swaroop Meena, Ravindra Naitam, Abhay Omprakash Shirale, Sirisha Adamala, B Amrutha, Ram Sakal Singh, Banshi Lal Mina, Hrittick Biswas, Nitin Gorakh Patil
更新时间: 2026-08-19
摘要: Soil organic carbon (SOC) plays a pivotal role in maintaining soil health, regulating climate, and enhancing agricultural productivity. However, the limited availability of spatial SOC information across Rajasthan constrains effective land use planning and site-specific soil management. Therefore, this study aimed to develop a geospatial framework for predicting and mapping SOC using machine learning (ML) techniques, quantify prediction uncertainty, and delineate Carbon Management Zones (CMZs) to support carbon-smart land use planning. By integrating environmental covariates—such as topographic indices, climate variables, vegetation indices, and remote sensing data—with principal component analysis and ML algorithms, we developed spatially continuous SOC prediction models and delineated CMZs. Among the predictors, elevation emerged as the most influential variable in the Random Forest (RF) model followed by BIO2 and soil depth, whereas elevation and soil depth were the dominant factors in the Support Vector Machine (SVM) model. The predicted SOC ranged from 0.01% to 1.35%. Model validation demonstrated that the RF model achieved superior predictive accuracy, with validation RMSE ranging from 0.081 to 0.168 and bias from −0.007 to 0.025 across soil depths, outperforming the SVM (RMSE: 0.114–0.194; bias: −0.033 to −0.018). The study region delineated five distinct CMZs characterized by unique landforms and carbon sequestration potentials. High SOC regions were primarily associated with forested uplands and the hill landscapes of the Aravalli Range, whereas lower SOC levels were observed in arid and semi-arid plains. Each CMZ was linked to targeted land use planning strategies to enhance SOC levels and sustainability. The proposed framework demonstrates the effectiveness of machine learning for SOC prediction and spatial stratification of management zones and offers a scalable methodology for supporting climate-smart agriculture and sustainable land management in similar dryland regions.

296. 题目: Temporal dynamics of soil dissolved organic matter influenced by biochar and microplastics: Insights from molecular and optical signatures
文章编号: N26081913
期刊: Journal of Hazardous Materials
作者: Zulqarnain Haider Khan, Ch. Tahir Mehmood, Hui Li, Zhao-Feng Yuan, Gang Li, Ruixia Han
更新时间: 2026-08-19
摘要: Microplastic (MP) pollution in soil has raised concerns about its impact on the dynamics of dissolved organic matter (DOM). Biochar (BC) influence MP-induced DOM dynamics, the specific mechanisms, especially for iron-modified biochar (FeBC), remain poorly understood. Here, we investigated the effects of BCs and FeBCs on DOM composition in paddy soil amended with biodegradable (polybutylene succinate, PBS) and conventional (polystyrene, PS) MPs over a 60-day incubation, using combined optical (EEM-PARAFAC) and ultrahigh-resolution mass spectrometric (FT-ICR MS) characterization. Unmodified BCs increased DOM solubilization and increased the relative enrichment and abundance of aromatic DOM components under the present incubation conditions, whereas FeBCs accelerated microbial activity (biological index, BIX: 1.11–1.47 vs. 0.76 in control) and DOM turnover. In PBS-amended soils, FeBC enhanced dissolved organic matter release (DOC: 474 mg/kg in PBS+FeBC6 vs. 279 mg/kg in control), leading to the accumulation of labile, low-molecular-weight organic fractions (molecular lability boundary index, MLBL index: 0.211 vs. 0.152 in control), and molecular turnover (time-decay slope: 0.069). In contrast, PS-enriched soils retained more aromatic, lignin-like, and recalcitrant DOM fractions. PBS treatments showed time-decay patterns (slope=0.007–0.069) consistent with rapid DOM transformations, while PS-amended soils maintained chemically stable DOM pool (slope=0.006–0.017). Thermodynamic modeling showed that PBS-induced transformations were largely spontaneous (ΔG° ≤ 0), while PS required energy input (ΔG° > 0). These findings highlight how BC and Fe modification distinctly regulate MP-induced DOM dynamics, with implications for carbon persistence and soil health.

297. 题目: Combination of microplastics-derived DOM with natural humic/fulvic acids accelerates atorvastatin photodegradation in freshwater environments
文章编号: N26081912
期刊: Water Research
作者: Xiaowei Wu, Shixiang Gao, Xiaoli Zhao, Mengjie Wang
更新时间: 2026-08-19
摘要: Microplastics-derived dissolved organic matter (MPs-DOM) in aquatic environments inevitably interacts with natural organic matter (NOM), yet their interaction kinetics and underlying mechanisms remain underexplored. Herein, we investigated the combination of DOM derived from polypropylene (PP) and polylactic acid (PLA) MPs with NOM (Suwanee River humic acid (SRHA) and Suwanee River fulvic acid (SRFA)) in freshwater systems. Results demonstrated that under UV irradiation, MPs-DOM derived from PP and PLA MPs could combine with coexisting SRHA/SRFA in water, forming MPs-DOM-SRHA and MPs-DOM-SRFA complexes. Notably, these complexes exhibited a differential structural composition and higher molecular weight compared to individual PP-DOM and PLA-DOM, particularly in the range of 10³ to 10⁴ Da. In addition, compared with the sole SRHA and SRFA, the MPs-DOM-SRHA/SRFA complexes significantly accelerated the photo transformation of atorvastatin (ATV). This phenomenon is attributed to the presence of highly unsaturated and phenolic compounds in MPs-DOM-SRHA/SRFA, which generated more oxidatively reactive oxygen species (ROS)—including hydroxyl radicals (•OH), superoxide anions (O₂•⁻), and singlet oxygen (¹O₂)—than SRHA and SRFA alone, thereby enhancing the photodegradation of ATV in water. These findings highlight that MPs-DOM-SRHA/SRFA complexes possess a distinct structural composition compared to individual MPs-DOM or natural organic matter (NOM), and may exhibit uncharacterized environmental behaviors and ecological risks in aquatic ecosystems.

298. 题目: Soil Organic Matter Adsorption on Iron Oxides and Kaolinite: Sequential and Selective Chemical Extractions
文章编号: N26081911
期刊: European Journal of Soil Science
作者: Ricardo Otto Oliveira, Eloana Janice Bonfleur, Vander Freitas Melo, Jeferson Dieckow, Bruna Ramalho, Edvaldo Rener Costa Cardoso
更新时间: 2026-08-19
摘要: Stabilization of organic matter (OM), and formation and of aggregates are some beneficial effects of organo‐mineral association in soils. The objective of this study was to quantify the contributions of outer‐ and inner‐spheres adsorptions on total OM/mineral association by sequential and selective chemical extractions. To establish a conceptual model of different adsorption stabilities, pure minerals (kaolinite—Kt, hematite—Hm and goethite—Gt), abundant on highly weathered soils, and concentrated organic matter fraction (HF‐treated Histosols: OM1, OM2, OM3 and OM4) were used. An additional treatment was planned to check the formation of the ternary complex OMCa 2+ Kt. The five steps of sequential OM extractions were: K 2 SO 4 ; sodium hexametaphosphate (HMP); sodium dithionite (DIT); sodium pyrophosphate (PYR) and; NaOH. The OM adsorbed by outer‐sphere on Hm, Gt and Kt were considered the sum of K 2 SO 4 + HMP (anion exchange) and adsorption by the inner‐sphere on Fe oxides the sum of DIT+PYR (extraction of ferrol groups) and on Kt the NaOH (extraction of aluminol group). The organic carbon contents of OM/mineral were high, indicating adequate saturation of minerals (OM/mineral ratio in the saturation step of 1:4) (g kg −1 ): OM/Hm—92.1; OM/Gt—98.6; OM/Kt—97.6. Goethite presented the highest decrease in specific surface area after OM association (OM4/Gt—reduction of 21.1%). There was no increase in OM‐mineral adsorption with Ca(NO 3 ) 2 solution to formation of ternary complexes OM(COO) − Ca 2+ Kt(SiO) − . In relation to the initial OM/mineral mixtures, the average percentages of residual OC at the end of sequential extractions (after last extraction with NaOH) were: Hm—61.5%; Gt—70.7%; KtH 2 O—60.3%; KtCa—60.8%. The greater stability of OM1/Hm (high residual OC) can be attributed to the higher occurrence of aromatic groups and the higher specific surface area of this mixture. The study concluded that there is strong adsorption by the inner‐sphere of OM on Hm, Gt and Kt; more stable the organo‐mineral complexes, lower rate of OM decomposition and higher carbon sequestration.

299. 题目: Dominance of temperature over organic matter composition and mineral protection in priming effect regulation
文章编号: N26081910
期刊: Geoderma
作者: Veronika Jílková, Martin Libra, Gerrit Angst, Martin Bartuška, Kateřina Čápová, Tomáš Hubáček, Kateřina Jandová, Jaroslav Kukla, Travis B Meador
更新时间: 2026-08-19
摘要: Consensus is emerging that the turnover of native soil organic matter (SOM) through the priming effect (PE) can be controlled by plant, soil and climate variables. Here, we apply a systematic approach to the quantitative assessment of the relative importance of plant C input quality, SOM persistence and temperature in regulating PE. We conducted a unique laboratory microcosm experiment comparing OM fractions originating from the topsoil and subsoil of a Central European temperate mixed forest incubated at two different temperatures, simulating the effects of climate warming. We repeatedly added 13C-labelled deciduous or coniferous leaf leachates or root exudates and determined PE. Our study emphasizes the critical role of temperature in regulating PE, with warming generally leading to reduced SOM turnover via PE and thus enhancing C storage in soils. Further, our results indicate the importance of OM composition together with mineral protection for PE regulation. Moreover, our findings challenge contemporary concepts that see mineral-associated OM as a stable SOM pool, and provide proof that at least a part of this pool is available with increased temperature. Our results thus provide new perspectives for future modelling and management efforts, and these may help promote enhanced SOM accumulation under future climate scenarios.

300. 题目: Snorkel-biochar coupling enhances organic matter and nitrogen pollutant removal while mitigating greenhouse gas emissions through spatial redox regulation in bioretention systems
文章编号: N26081909
期刊: Water Research
作者: Ruohan Li, Wenying Sun, Yuepeng Deng, Hengxin Liu, Mingyue Yang, Yueming Han, Lixun Zhang
更新时间: 2026-08-19
摘要: Bioretention systems treating urban stormwater face a trade-off between organic matter/nitrogen pollutant removal and greenhouse gas (GHG) emissions. A snorkel-biochar composite bioretention system (SN.BC) was developed to address this trade-off. Over 182 days, SN.BC maintained stable treatment under varying antecedent dry days (ADDs) and pollutant loadings. From Day 16 onward during the initial 112-day operation, the mean removal efficiencies of COD, TN, NO3−-N, and NH4+-N were 95.0 ± 0.4%, 86.5 ± 0.5%, 97.9 ± 1.2%, and 93.0 ± 0.3%, respectively. GHG emissions were assessed under varying ADDs and pollutant loadings. Across these conditions, the mean global warming potential calculated from 8-h post-drainage emissions for SN.BC was 59.4% lower than for Control. Integrated evidence suggested that the snorkel may have facilitated interlayer electron transfer and altered spatial redox stratification, whereas biochar may have provided microbial habitats and local electron-buffering capacity. These changes were associated with greater functional potential for nitrification and denitrification and lower methanogenic potential. The enrichment of ammonia-oxidizing and nitrite-oxidizing microorganisms in the upper layer, together with denitrification-associated taxa in the middle and bottom layers, was consistent with spatial differentiation of nitrogen transformation potential. Moreover, the co-occurrence of genes related to CH4 oxidation and NO3−/NO2− reduction, together with enrichment of the archaeal genus Candidatus Methanoperedens, suggested that denitrification-dependent anaerobic methane oxidation-associated metabolism may have contributed to concurrent NO3−/NO2− removal and CH4 mitigation. This snorkel-biochar strategy offers a promising route for coupling organic matter and nitrogen removal with GHG mitigation through spatial redox regulation.