1. 题目: Machine learning in clarifying complex relationships: Biochar preparation procedures and capacitance characteristics
期刊: Chemical Engineering Journal
作者: Yuxuan Sun, Peihao Sun, Jixiu Jia, Ziyun Liu, Lili Huo, Lixin Zhao, Yanan Zhao, Wenjuan Niu, Zonglu Yao
摘要: Supercapacitors as a new type of energy storage device play an important role in the development of renewable energy. Activated biochar-based electrode materials has good energy storage potential because of useful physicochemical properties and renewability. The optimal preparation method for biochar-based electrodes for supercapacitors is difficult to determine experimentally due to the complexity of influencing factors. Therefore, three machine learning models were developed to describe the relationship between the preparation process and the energy storage characteristics of activated biochar. The Gradient Boosting Regression (GBR) model provided the best prediction, with an R2 value of 0.93. Interestingly, the heating rate was the most important factor affecting the specific capacitance of activated biochar and showed a significant negative correlation, with a feature importance of 35.08 %. In addition, Micropore volume proportion and specific surface area showed a significant positive correlation with specific capacitance, with feature importance of 15.39 % and 9.23 %, respectively. Significantly, the specific capacitance could be improved by increasing the added amount of N source and activator and a higher activation temperature, as well as using a shorter activation time and slower heating rate during preparation. This study provides new insights into the applications of activated biochar for energy storage through data analysis.
2. 题目: Vertical variations of bacteriohopanepolyols near the Changjiang Estuary waters: Implications for marine hypoxia and bacterial activities
期刊: Chemical Geology
作者: Meiling Yin, Liqin Duan, Jinming Song, Jiawei Kan, Huamao Yuan, Xuegang Li, Yingxia Wang
摘要: Bacteriohopanepolyols (BHPs) are widespread in bacteria and are used as lipid biomarkers for specific bacterial activities and environmental changes. However, deposition and degradation dynamics of BHPs are still poorly constrained in marine settings, thereby affecting their reliability as biomarkers. Here, we investigated BHPs in the water columns and sediments near the Changjiang Estuary to evaluate their origins, preservation and responses to seawater hypoxia and bacterial activities. Results indicated that bacteriohopanetetrol stereoisomer (BHT-isomer) in this area was predominantly BHT- produced by Ca. Scalindua, present in hypoxic bottom seawater. 2-Methyl BHT and nitrogen-fixing cyanobacteria showed similar vertical distribution in the water column, as did amnio-BHPs (aminotetrol and aminopentol) and the aerobic methane oxidation (AMO) gene . 2-Methyl BHT, aminotetrol and aminopentol were thought to primarily derive from cyanobacteria and aerobic methanotrophs in seawater, respectively, despite other potential sources. Depth profiles suggest that in-situ production in sediments is not a major contribution to sedimentary BHPs, compared to the export and deposition from the water column. The abundances of unsaturated BHT and amino-BHPs in surface sediments were decreased compared with those in the water column, indicating that unsaturated BHT and amino-BHPs appear to undergo a certain degree of early diagenetic degradation. BHT-isomer and 2-Methyl BHT preserved preferentially over amino-BHPs. Additionally, BHT-isomer significantly correlated with anammox functional gene -16S rRNA, and 2-Methyl BHT significantly correlated with nitrogen-fixing functional gene . This indicated that BHT-isomer and 2-Methyl BHT are suitable as biomarkers for anammox and cyanobacterial nitrogen fixation. The BHT-isomer ratio accurately reflects the situation in the water column and appears to be a very appropriate proxy for hypoxia. Conversely, sedimentary aminotetrol and aminopentol underestimate the importance of aerobic methane oxidation in seawater, as these are more rapidly degraded upon deposition to the sea floor.
3. 题目: Direct Salinity Effect on Absorbance and Fluorescence of Chernozem Water-Extractable Organic Matter
期刊: Aquatic Geochemistry
作者: Vladimir A Kholodov, Natalia N Danchenko, Aliya R Ziganshina, Nadezhda V Yaroslavtseva, Igor P Semiletov
Soil-derived dissolved organic matter (DOM) has a significant impact on aquatic ecosystems. Identifying the fluorescence signatures of DOM from different soils in river and sea waters can provide valuable insights into its migration patterns. This makes crucial assessing the contributions of pH, salinity, and other milieu parameters to the variability of DOM optical properties. Present study investigates the changes in DOM of Chernozems under varying salinity using UV–visible absorbance spectroscopy and 3D-fluorescence spectroscopy coupled with parallel factor analysis (EEMs-PARAFAC). Water-extractable organic matter (WEOM) extracted from soils of two field experiments of contrasting land use: long-term bare fallow (LTBF) and annually mown steppe (Steppe), was used as a proxy for DOM. Diluted extracts were incubated with varying NaCl concentrations in the dark and then examined. Steppe WEOM exhibited fair constancy of optical parameters under increasing salinity, while significant changes of the optical indices and of PARAFAC components’s loadings were observed for LTBF WEOM. The remarkable stability of the Steppe WEOM can be attributed to its chemical diversity. Two distinct and sufficiently stable humic-like PARAFAC components have the potential to serve as markers of Chernozem DOM. The findings clearly demonstrate that salinity itself slightly reduces absorption and fluorescence and changes some optical indices of WEOM of Chernozems.
4. 题目: Blue carbon additionality: New insights from the radiocarbon content of saltmarsh soils and their respired CO2
期刊: Limnology and Oceanography
作者: Alex Houston, Mark H Garnett, William E N Austin
摘要: International policy frameworks recognize the net drawdown and storage of atmospheric greenhouse gases through management interventions on blue carbon ecosystems (saltmarshes, mangroves, seagrasses) as potential emissions offset strategies. However, key questions remain around the “additionality” of the carbon sequestered by these ecosystems, and whether some fraction of the organic carbon (OC) that does not derive from in situ production (allochthonous) should be included in carbon budgets. This study compares the radiocarbon (14C) contents of saltmarsh soils and CO2 evolved from aerobic laboratory incubations to show that young OC is preferentially respired over aged OC, and that the latter is also vulnerable to remineralization under oxic conditions. This highlights that management interventions which reduce the exposure of saltmarsh soils to oxic conditions support the inclusion of some portion of allochthonous OC in carbon budgets. Elevated temperature incubations provide preliminary evidence that the predominant source of respired OC will not change under predicted future warmer conditions. Saltmarsh typology also influences the 14C content of both the bulk soil and respired CO2, highlighting the importance of site selection for optimized blue carbon additionality.
5. 题目: Migration and morphological transformation patterns of heavy metals on sludge cells and extracellular polymeric substances (EPS) under the influence of different treatments
期刊: Environmental Science and Pollution Research
作者: Xiaoyu Jia, Yuxin Wang, Miaomiao Zhao, Fan Zhang, Chen Li, Degang Ma
The impediment of sludge resource utilization stems from the presence of heavy metals within the sludge matrix. To optimize heavy metal removal techniques from undried sludge, it is essential to study the distribution of heavy metals in the sludge flocs structure and the changes in morphology in the sludge cells after different treatments. In this study, the sludge was subjected to chemical treatments using citric acid (CA), EDTA, and saponin, as well as electrokinetic treatment at 2 V/cm. The distribution and migration of Cu, Ni, and Zn in sludge flocs after various treatment methods were analyzed. The heavy metals were found to migrate from intracellular to extracellular polymeric substances (EPS) without causing extensive sludge cell lysis. They gradually diffused outward with the dispersion of the EPS layer. The migration efficiency of the three heavy metals in the sludge flocs was Zn, Ni, and Cu. This was mainly related to the initial distribution and morphology of the heavy metals. Under the influence of chemicals and an electric field, the acid-soluble and reducible heavy metals in the cells partially migrated to the EPS, while the stable heavy metals transformed into an unstable state. Furthermore, the order of chemical reagents in terms of their effect on the migration efficiency of heavy metals was CA > EDTA > Saponin, owing to the varying binding strengths of heavy metals and their impact on the degree of loosening of the EPS. Especially after CA treatment a greater proportion of Cu, Ni, and Zn were transferred from the cells to the EPS. The acidification effect near the anode during electrokinetic treatment intensifies the migration of heavy metals. This study provides basic research for subsequent engineering optimization aimed at removing heavy metals from sludge.
6. 题目: Graph-Based Method for Calibration of High-Resolution Mass Spectra of Natural Organic Matter
期刊: Analytical Chemistry
作者: Qiong Pan, Chen He, Quan Shi
摘要: Inaccuracies in ion detection and signal processing can undermine confidence in the molecular formula assignment of high-resolution mass spectrometry, which relies on precise matching of the mass-to-charge ratio (m/z). This study proposes a novel graph-based spectra calibration method, MSCMcalib, which implements coordinate transformation and pattern detection. MSCMcalib maps uncalibrated m/z data onto a modified 2D mass defect plot, facilitating the automatic calibration of detected lines, i.e., the calibration of uncalibrated peaks aligned with these lines. The “propagation” method is subsequently employed to accurately and automatically calibrate 605 m/z values across multiple lines, encompassing 98% of the m/z range. The calibrated m/z values divide the m/z range of the spectrum into multiple subintervals, with each subinterval undergoing a process of “scaling” calibration. The utilization of narrower partitions effectively mitigates divergence issues at both ends that arise from the polynomial fitting of errors against m/z. The effectiveness of MSCMcalib is validated through the calibration of SRFA data with m/z error ranges spanning from −10 to −6 ppm, resulting in an additional assignment of 11%–30% more molecular formulas compared to the quadratic fitting calibration.
7. 题目: Advanced Treatment of Wastewater by Biological Ion-Exchange Resin for Dissolved Organic Carbon and Pharmaceutical Removal
期刊: ACS ES&T Water
作者: Yunbao Yan, Sunyuan Zong, Chendong Shuang, Qing Zhou, Rong Ji, Ai-Min Li
摘要: The biological ion exchange (BIEX) process has been proposed by utilizing a simultaneous biodegradation and ion exchange process for reducing the brine waste production from ion-exchange resin (IER) regeneration. In this work, we investigated two BIEX systems for biological effluent treatment, employing MAEX resin and Purolite A860 resin, which were compared with bioactivated carbon (BAC) and traditional activated sludge (AS). Over 0–120 days of operation, dissolved organic carbon (DOC) removal values were 52.5% (bio-MAEX), 48.1% (bio-A860), 18.5% (BAC), and 10.5% (AS). Both IERs could enhance biological activity, as indicated by their higher ATP and protein levels. Consequently, both BIEX systems were capable of a rapid restart within 15 days after storage at 4 °C, achieving stable DOC removal values of 45% (bio-MAEX) and 40% (bio-A860). As the ion exchange/adsorption reached equilibrium, the biocontribution to DOC removal for both BIEX systems increased from 35% (0–120 days) to 63.5% (121–240 days). Furthermore, the removal efficiencies for pharmaceuticals (ibuprofen, indomethacin, diclofenac, roxithromycin, and clarithromycin) were 92.7% (bio-MAEX), 90.9% (bio-A860), 89.5% (BAC), and 86.3% (AS). The biocontribution values to pharmaceutical removal were evaluated as 53.9 ± 6.4% (bio-MAEX), 47.5 ± 11.8% (bio-A860), and 38.9 ± 11.0% (BAC). The results showed that BIEX can perform well in the advanced treatment.
8. 题目: Recycling alkali lignin-derived biochar with adsorbed cadmium into cost-effective CdS/C photocatalyst for methylene blue removal
期刊: Waste Management & Research
作者: Peng Yu, Ronghao Zhuang, Hui Liu, Zhiguo Wang, Chun Zhang, Qiongchao Wang, Hongyu Sun, Wei Huang
摘要: Cadmium (Cd)-enriched adsorbents wastes possess great environmental risk due to their large-scale accumulation and toxicity in the natural environment. Recycling spent Cd-enriched adsorbents into efficient catalysts for advanced applications could address the environmental issues and attain the carbon neutral goal. Herein, a facile strategy is developed for the first time to reutilize the alkali lignin (AL)-derived biochar (ALB) absorbed with Cd into cadmium sulphide (CdS)/C composite for the efficient methylene blue (MB) removal. The ALB is initially treated with Cd-containing solution, then the recycling ALB samples with adsorbed Cd are converted to the final CdS/C composite using NaS2 as the sulphurizing reagent for vulcanization reaction. The optimal ALB400 demonstrates a high adsorption capacity of 576.0 mg g−1 for Cd removal. Then the converted CdS/C composite shows an efficient MB removal efficiency of 94%. The photodegradation mechanism is mainly attributed to carbon components in the CdS/C composite as electron acceptor promoting the separation of photoelectrons/holes and slowing down the abrasion of CdS particles. The enhanced charge transfer and contact between the carrier and the active site thus improves the removal performance and reusability. This work not only develops a method for removing Cd from wastewater effectively and achieving the waste resource utilization but also further offers a significant guidance to use other kinds of spent heavy metal removal adsorbents for the construction of low-cost and high value-added functional materials.
9. 题目: Holocene organic matter composition in relation to relative sea level stands and associated morphometric changes of a lagoonal system
期刊: Marine Geology
作者: V Carvalho, L Gonzalez, C Bueno, C Segura, S.R. Bottezini, A Leonhardt, D Diniz, P Dentzien-Dias, L Perez, H Evangelista, M.V. Licínio, H Inda, L Bergamino, J Weschenfelder, E Barboza, F Garcia-Rodriguez
摘要: Garzón Lagoon is a temperate shallow coastal lagoon influenced by sea level variation. A study on the isotopic composition of Holocene sedimentary organic matter was performed. Although the system was subject to significant changes in sea level, leading to important changes in the lagoon morphometry during the Holocene, the composition of the organic matter was rather surprisingly constant, being dominated by particulate organic matter of marine origin, and to a lesser extent of terrestrial origin. By ~5000 yr BP, the sea level was +5 m amsl, and the lagoon displayed the largest morphometric dimensions. Once the sea level decreased towards 3000 yr BP and present times, the lagoon area progressively decreased. Even though we inferred significant changes in morphometry, the composition of the organic matter remained relatively constant, as the lagoon was always connected to the ocean, a condition that remains today, at least intermittently during storms or heavy rains. Only after the 1960s, a slight change in the organic matter composition was detected, consisting of a decrease in particulate organic matter of terrestrial origin.
10. 题目: Spatiotemporal dynamics of dissolved organic matter and disinfection by-products formation potential of Shengzhong Lake in southwest China
期刊: Environmental Science and Pollution Research
作者: Yunwen Wang, Dong Ren, Yunxiang Li, Zhineng Hao, Jingfu Liu
The quality and quantity of dissolved organic matter (DOM) in lakes as well as its environmental effects associated with the unintended disinfection by-products (DBPs) have received continuous attention. This work investigated the spatiotemporal dynamics of DOM in Shengzhong Lake in southwest China and the formed DBPs during the chlorine disinfection process. The results showed that lake water in summer had significantly higher dissolved oxygen and dissolved organic carbon than that in winter. In contrast, DOM in winter demonstrated an obviously higher aromaticity and molecular weight than that in summer. Four fluorescence components, i.e., terrestrial humic-like substances (C1), protein-like substances (C2), and microbial humic-like substances (C3 and C4), were identified, and their relative abundance followed in the order of C3 > C4 > C2 > C1 in winter and C4 > C3 > C1 > C2 in summer. The formation potential of trihalomethanes and haloacetic acids in winter was higher and lower than that in summer, which was mainly ascribed to the content of aromatic and hydrophobic substances. Compared to the significant seasonal dynamic, the spatial variation of DOM and the formed DBPs was not obvious. This work sheds light on the spatial-temporal distribution of DOM and the potentially formed DBPs in Shengzhong Lake, and will be helpful for understanding the biogeochemical cycle of carbon and assessing the drinking water safety.
11. 题目: Dynamic distribution and photochemical-microbial coupling degradation of dissolved organic matter in a large river-Influenced Bay
期刊: Marine Chemistry
作者: Mingzheng Zhang, Xinke Wang, Shengkang Liang, Haoyang Ma, Yanqun Yang, Hongguan Li, Shanshan Li, Xihua Yu
摘要: A large river-influenced offshore area is the junction where land and open sea meet, which is important in the biogeochemical processes of dissolved organic matter (DOM). Because hydrodynamic and biogeochemical processes are complex, processes such as the photochemical and microbial degradation of DOM are poorly understood. In this study, to further understand the degradation mechanisms of DOM from different sources, water was sampled from three cruises during autumn 2018 and spring and summer 2019 in Laizhou Bay (LZB), as this bay is greatly influenced by the Yellow River. Field incubation experiments examining the riverine, mixed, and marine DOM photochemical and microbial degradation processes alone or in combination were conducted onboard. Due to the dual influence of the Yellow River input and phytoplankton autogenous production, dissolved organic carbon (DOC) and chromophoric DOM (CDOM) show relatively conservative mixing behaviour with maximum values in summer, and the S275–295 gradually increases from the river to nearshore. In addition, it is indicated that higher primary productivity from large nutrient inputs in areas with moderate salinity during the summer is often accompanied by higher bioavailability DOM based on field investigation results. Various sources of DOM have different sensitivities to photochemical and microbial degradation due to their components and properties. Riverine DOM is susceptible to photochemical degradation, while marine DOM is more susceptible to microbial degradation. Moreover, the low-molecular-weight organic matter produced by photochemical degradation effectively promotes the microbial degradation of DOM from riverine sources, whereas photodegradation from mixed and marine sources do not significantly increase the biodegradation efficiency due to the low content of aromatic substances. Furthermore, photoammonification and bioammonification of autochthonous and allochthonous DOM may be the potential processes driving ammonia regeneration.
12. 题目: Functionalized typha biochar for antibiotic removal via low‐carbon integrated method: Performance and mechanism analyses
期刊: Clean - Soil Air Water
作者: Jingrong Liu, Jing Wen, Jingtao Hu, Yuxuan Ma, Xiaojing Wang, Huiqin Li
摘要: Antibiotic residues in water represent an urgent environmental challenge. To efficiently remove these residues, a low‐carbon integrated biochar synthesis method was proposed, and an optimized typha biochar (TBIK) was prepared. Compared with the biochar prepared by a conventional two‐step carbonization and activation method (TBTK), the TBIK preparation process reduced energy consumption by 43849.58 J and cut carbon dioxide emissions by 32.80%. TBIK exhibited a large surface area of 1252.40 m2/g and rapidly achieved an equilibrium removal efficiency of 99.95% within 20 min for simulated antibiotics wastewater. Furthermore, TBIK possessed more number of functional groups than TBTK, especially O‐H and C‐S groups. The adsorption stability and tolerance of TBIK in solutions with different ionic strengths and coexisting anions were examined. Characterization techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FT‐IR), and X‐ray photoelectron spectroscopy (XPS) as well as Brunauer, Emmett and Teller (BET) analyses were employed to elucidate the morphology and adsorption mechanism of the adsorbent. The microporous structure and abundance of functional groups are key to the excellent adsorption capabilities of TBIK. Thus, this integrated method for biochar production, optimized for treating antibiotic wastewater, holds significant potential for future applications.
13. 题目: Carbon Fate, Iron Dissolution, and Molecular Characterization of Dissolved Organic Matter in Thawed Yedoma Permafrost under Varying Redox Conditions
期刊: Environmental Science & Technology
作者: Matheus Sampaio Carneiro Barreto, Rucha P Wani, Aleksandar I Goranov, Tyler D Sowers, Matthew Fischel, Thomas Alexander Douglas, Patrick G Hatcher, Donald L Sparks
摘要: Permafrost soils store ∼50% of terrestrial C, with Yedoma permafrost containing ∼25% of the total C. Permafrost is undergoing degradation due to thawing, with potentially hazardous effects on landscape stability and water resources. Complicating ongoing efforts to project the ultimate fate of deep permafrost C is the poorly constrained role of the redox environment, Fe-minerals, and its redox-active phases, which may modulate organic C-abundance, composition, and reactivity through complexation and catalytic processes. We characterized C fate, Fe fractions, and dissolved organic matter (DOM) isolates from permafrost-thaw under varying redox conditions. Under anoxic incubation conditions, 33% of the initial C was lost as gaseous species within 21 days, while under oxic conditions, 58% of C was lost. Under anoxic incubation, 42% of the total initial C was preserved in a dissolved fraction. Lignin-like compounds dominated permafrost-thaw, followed by lipid- and protein-like compounds. However, under anoxic incubation conditions, there was accumulation of lipid-like compounds and reduction in the nominal oxidation state of C over time, regardless of the compound classes. DOM dynamics may be affected by microbial activity and abiotic processes mediated by Fe-minerals related to selective DOM fractionation and/or its oxidation. Chemodiversity DOM signatures could serve as valuable proxies to track redox conditions with permafrost-thaw.
14. 题目: Geochemical Constraints and Astronomical Forcing on Organic Matter Accumulation of Marine–Continental Transitional Shale Deposits in the Qinshui Basin during the Carboniferous–Permian Transition
期刊: ACS Earth and Space Chemistry
作者: Chengang Lu, Ping Gao, Robert Lee Kong Tiong, Yue Feng, Gang Li, Guangming Meng, Yichuan Yu, Xianming Xiao
摘要: During the Carboniferous–Permian transition, the paleoclimate of Earth transitioned from an icehouse to a greenhouse state, severely impacting the burial patterns of organic matter (OM). Within the Upper Carboniferous–Lower Permian Taiyuan–Shanxi formations (TY–SX) in the Qinshui Basin, North China, lie a series of marine–continental transitional organic-rich shale deposits. However, the mechanism behind the enrichment of OM in these shale deposits, formed during the icehouse–greenhouse transition, remains unclear. To address this issue, a suite of transitional shale deposits was investigated by using geochemical and astronomical cyclostratigraphic analyses. The results show that the depositional age of TY–SX spans from 293.65 to 300.64 ± 0.412 Ma. The depositional environments of these TY–SX shales tended toward oxidation, with the TY shales slightly more reducing than the SX shales. The paleoclimate of the TY–SX shales suggests warm and humid environments with comparatively strong chemical weathering intensity. Primary productivity in these TY–SX shales was estimated to be low, but the influx of terrigenous detritus was robust, driving OM accumulation through terrigenous inputs. The 405-kyr astronomical cycle had a forcing effect on the paleoenvironment variations, and the 173-kyr astronomical cycle showed a covariance with OM enrichment. The TY shales exhibited a stable and moderate sedimentation rate, with enhanced terrigenous OM input leading to OM enrichment, whereas the OM contents of the SX shales, deposited under conditions of low primary productivity and oxidation, experienced dilution of the OM content owing to detrital inputs.
15. 题目: Fire Impacts on the Soil Metabolome and Organic Matter Biodegradability
期刊: Environmental Science & Technology
作者: Jacob P VanderRoest, Julie A Fowler, Charles C Rhoades, Holly K Roth, Corey D Broeckling, Timothy S Fegel, Amy M McKenna, Emily K Bechtold, Claudia M Boot, Michael J Wilkins, Thomas Borch
摘要: Global wildfire activity has increased since the 1970s and is projected to intensify throughout the 21st century. Wildfires change the composition and biodegradability of soil organic matter (SOM) which contains nutrients that fuel microbial metabolism. Though persistent forms of SOM often increase postfire, the response of more biodegradable SOM remains unclear. Here we simulated severe wildfires through a controlled “pyrocosm” approach to identify biodegradable sources of SOM and characterize the soil metabolome immediately postfire. Using microbial amplicon (16S/ITS) sequencing and gas chromatography–mass spectrometry, heterotrophic microbes (Actinobacteria, Firmicutes, and Protobacteria) and specific metabolites (glycine, protocatechuate, citric cycle intermediates) were enriched in burned soils, indicating that burned soils contain a variety of substrates that support microbial metabolism. Molecular formulas assigned by 21 T Fourier transform ion cyclotron resonance mass spectrometry showed that SOM in burned soil was lower in molecular weight and featured 20 to 43% more nitrogen-containing molecular formulas than unburned soil. We also measured higher water extractable organic carbon concentrations and higher CO2 efflux in burned soils. The observed enrichment of biodegradable SOM and microbial heterotrophs demonstrates the resilience of these soils to severe burning, providing important implications for postfire soil microbial and plant recolonization and ecosystem recovery.
16. 题目: Elucidating Dissolved Organic Sulfur in the Coastal Environment by Improved Online Liquid Chromatography Coupled to FT-ICR Mass Spectrometry
期刊: Journal of Geophysical Research: Oceans
作者: Shuang Chen, Yulin Qi, Qiaorong Xie, Chao Ma, Shujun Zhong, Libin Wu, Pingqing Fu
摘要: Dissolved organic sulfur (DOS) is an important component of dissolved organic matter (DOM) and widely exists at the land-atmosphere interface. However, the characterization of DOS at the molecular level among different environmental samples in coastal regions has not been sufficiently focused. Here, we investigated DOS in aerosol, rainwater, and river water samples in Shanghai using an improved method–online liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC-FT-ICR MS). This system is utilized to separate DOS from complicated environmental matrices. The results showed that the average relative abundance of DOS in three different environmental media (aerosol, rainwater, and river water samples) accounted for 16.8%, 21.9% and 13.1%, respectively. The common molecules of the three mediums in coastal Shanghai contain an abundance of aromatic and aliphatic DOS of anthropogenic origin in addition to the natural sources of sea spray. Notably, results from a new structural classification scheme for DOS demonstrate that anthropogenic sulfonates and their derivatives are widely spread, although their molecular diversity in different medium was recorded due to complex environmental conditions and diverse sources.
17. 题目: Properties of humin isolated from Polish arable soils: The most recalcitrant fraction of soil organic matter that prevent soil degradation
期刊: Land Degradation & Development
作者: Jerzy Weber, Maria Jerzykiewicz, Aleksandra Ukalska-Jaruga, Irmina Ćwieląg-Piasecka, Elżbieta Jamroz, Andrzej Kocowicz, Magdalena Debicka, Jakub Bekier, Lilla Mielnik, Romualda Bejger, Agnieszka Grabusiewicz
摘要: The purpose of the research was to determine the molecular properties of humin (HUM) determined by elemental composition, as well as spectroscopic 13C Magic Angle Splitting Cross Polarisation Nuclear Magnetic Resonance (13C MAS CP NMR), Fourier transformed infrared, electron paramagnetic resonance and scanning electron microscope energy-dispersive x-ray (SEM–EDX) techniques. Soil samples were isolated from the mollic horizon of Phaeozem and Chernozem arable soils derived from different parent materials in Poland. The HUM was isolated as the fraction that was remined after exhaustive extraction of the humic and fulvic acids by NaOH and was followed by removal of the mineral fraction with HF/HCl treatment. The results obtained indicated that the HUM structures isolated by the adopted method are a chemically heterogeneous conglomerate, composed of a complex of many strongly combined units of organic substances. This fraction indicated a highly condensed structure with a predominance of aromatic components (predominating over chain forms ranging from 7.05% to 10.32%) and hydrophobic reactive moieties. The share of hydrophobic forms ranges from 77.41% to 80.83%. The ash content, ranging from 22.89% to 54.50%, as well as SEM–EDX used indicated that the HUM isolated with the adopted procedure is strongly associated with the mineral components of the soil. The aromatic part of HUM is strongly associated with the mineral components of the soil, what provides their stability in the environment. These observations confirm the high resistance of HUM to decomposition and indicate the great importance of this fraction in carbon sequestration and preventing soil degradation.
18. 题目: Functionalized organo-mineral composites of biochar for the effectual immobilization of arsenic in contaminated soil
期刊: Journal of Soils and Sediments
作者: Jahangir Ahmad, Abdullah S Al-Farraj, Munir Ahmad, Hamed Ahmed Al-Swadi, Mohammad I Al-Wabel
Arsenic (As) pollution has become one of the major environmental challenges around the world as it is a carcinogenic and toxic metal. Efficient removal of As from soil on sustainable basis is of critical importance.
Organo-mineral composites of date palm-derived biochar (BC) produced at 400°C (B4) and 600°C (B6) were synthesized by intercalation of 10% (B4-C10 and B6-C10) and 20% (B4-C20 and B6-C20) of nano-sized bentonite. After the characterization, the synthesized amendments applied to As-contaminated soils (0 mg kg−1 (OS), 100 mg kg−1 (S1) and 200 mg kg−1 (S2) of As concentrations) at 0% (CK), 1%, and 3% (w/w) application rate under greenhouse conditions with maize (Zea mays L.) as test crop.
The application of 3% B6-C20 resulted in 21% reduced availability of As than CK, indicating the highest As immobilization. The similar treatment resulted in 71%, 64%, and 52% higher shoot length in S2, S1, and OS, respectively, while 66%, 67%, and 56% higher root length in S2, S1, and OS, respectively, than CK. B6-C20 with 3% application rate resulted in 38% and 34% reduced root As concentration in S1 and S2, respectively, while 58% and 59% reduced As in shoots in S1 and S2, respectively, than CK. The similar treatment resulted in the highest phosphorus (3455 mg kg−1) and potassium (755 mg kg−1) in shoots. Phytoextraction indices showed that B6 composites with nano-bentonite can be used for the phytostabilization of As using maize plants.
The outcomes of this study indicated that the amendments could potentially be used for the immobilization of As and improving maize plant growth.
19. 题目: Peatlands Versus Permafrost: Landscape Features as Drivers of Dissolved Organic Matter Composition in West Siberian Rivers
期刊: Journal of Geophysical Research: Biogeosciences
作者: Sommer F Starr, Karen E Frey, Laurence C Smith, Anne M Kellerman, Amy M McKenna, Robert G M Spencer
摘要: West Siberia contains some of the largest soil carbon stores on Earth owing to vast areas of peatlands and permafrost, with the region warming far faster than the global average. Organic matter transported in fluvial systems is likely to undergo distinct compositional changes as peatlands and permafrost warm. However, the influence of peatlands and permafrost on future dissolved organic matter (DOM) composition is not well characterized. To better understand how these environmental drivers may impact DOM composition in warming Arctic rivers, we used ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry to analyze riverine DOM composition across a latitudinal gradient of West Siberia spanning both permafrost-influenced and permafrost-free watersheds and varying proportions of peatland cover. We find that peatland cover explains much of the variance in DOM composition in permafrost-free watersheds in West Siberia, but this effect is suppressed in permafrost-influenced watersheds. DOM from warm permafrost-free watersheds was more heterogenous, higher molecular weight, and relatively nitrogen enriched in comparison to DOM from cold permafrost-influenced watersheds, which were relatively enriched in energy-rich peptide-like and aliphatic compounds. Therefore, we predict that as these watersheds warm, West Siberian rivers will export more heterogeneous DOM with higher average molecular weight than at present. Such compositional shifts have been linked to different fates of DOM in downstream ecosystems. For example, a shift toward higher molecular weight, less energy-rich DOM may lead to a change in the fate of this material, making it more susceptible to photochemical degradation processes, particularly in the receiving Arctic Ocean.
20. 题目: Effects of brackish water irrigation and biochar application on fertility, enzyme activity, and winter wheat yield in coastal saline-alkali soils
期刊: Land Degradation & Development
作者: Wei Wu, Hongxing Chai, Peiling Gao, Penghao Gao, Xue Zhang, Mengzhao Li, Xianglin Guo, Qingxin Lv
摘要: Soil salinization is a common form of land degradation in coastal regions. The Yellow River Delta is a typical coastal saline-alkali soils distribution region, with saline-alkali soils accounting for nearly half of the total area of the region. In view of the lack of fresh water in the region, the use of brackish water and biochar made from agricultural waste to improve coastal saline-alkali soils has a good application prospect, but there are fewer studies on this at present. To explore water conservation, fertilization, and yield enhancement solutions appropriate for saline-alkali soils in the Yellow River Delta region, this study focused on investigating the impact of biochar addition on the fertility, enzyme activity, and winter wheat yield in saline-alkali soils under brackish water irrigation conditions. The research was conducted through outdoor potting experiments, utilizing a local moderately saline-alkali soil as the subject of study. The study design established three different irrigation water mineralization levels (0, 2, and 4 g L−1) during the research. Two types of biochar, wheat straw biochar (WB) and corn straw biochar (CB) were used with four different applications (0, 5, 10, and 20 t ha−1). There were 21 treatments; each replicated three times. The research findings indicated that brackish water irrigation adversely affected soil fertility and soil alkaline phosphatase activity and soil sucrase activity but increased soil urease activity and soil peroxidase activity. In contrast, biochar application improved soil fertility and enzyme activities. The soil fertility and enzyme activities of K2Y10 treatment was higher than that of CK (fresh water, no biochar application) except for soil total nitrogen, which increased by 5.5%–71.2%. While brackish water irrigation decreased winter wheat yield. Biochar application increased winter wheat yield, with the K2Y10 treatment showing the highest yield under brackish water irrigation conditions, and increased by 17.7% compared to CK. In conclusion, the study recommends a combination of water-saving measures, fertilizer cultivation, and yield increase strategies to improve saline-alkali soils in the Yellow River Delta region effectively. Specifically, irrigating with 2 g L−1 brackish water and application 10 t ha−1 of CB demonstrated greater efficacy in addressing the challenges of saline-alkali soils in the region.