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17681. 题目: Molecular and stable isotope analysis (δ13C, δ2H) of sedimentary n-alkanes in the St. Lawrence Estuary and Gulf, Quebec, Canada: importance of even numbered n-alkanes in coastal systems
文章编号: N22010919
期刊: Organic Geochemistry
作者: Anic Imfeld, Alexandre Ouellet, Peter Douglas, Gregor Kos, Yves Gélinas
更新时间: 2022-01-09
摘要: Sediments comprise a multitude of inorganic and organic components, with much of the composition of the organics still not fully characterized. Our research targeted n-alkanes, to determine whether compound specific carbon and hydrogen isotope analysis allows for their source identification in coastal sediments. Here, we map the current abundances and sources of straight chain n-alkanes in sediments of the St. Lawrence Estuary and Gulf using molecular (diagnostic ratios) and isotopic fingerprinting (δ13C, δ2H). n-Alkane abundances (117.11 ± 1.61 to 418.64 ± 70.20 µg/g OC), carbon preference index (CPI; 1.95 ± 0.05 to 5.09 ± 0.10), average chain length (ACL; 28.36 ± 0.02 to 28.97 ± 0.01), proportion of aquatic submerged plants and terrestrial plant inputs (Paq; 0.295 ± 0.003 to 0.377 ± 0.002), terrigenous aquatic ratio (TAR; 3.43 ± 0.16 to 7.99 ± 0.05), and n-alkane ratio (NAR; 0.169 ± 0.011 to 0.584 ± 0.011) values varied along the terrestrial-marine continuum. Large differences in the concentration weighted average (WA) δ13C and δ2H for odd and even n-alkanes were found, with WA δ13C ranging from -30.9 ± 0.3 to -33.4 ± 0.09 ‰ and -28.8 ± 0.01 to -32.3 ± 0.2 ‰, respectively, and 165.6 ± 3.6 to -200.8 ± 2.4 ‰ and -96.0 ± 2.8 to -158.7 ± 2.1 ‰ for δ2H. The diagnostic ratios were shown to misrepresent the input sources of organic matter (OM) and were inaccurate as source indicators when more than one OM source was present. With the addition of compound specific δ13C and δ2H analysis of n-alkanes, it was determined that the n-alkanes were predominantly derived from natural, rather than anthropogenic sources, with variations being driven by geographic changes in vegetation type and differing ratios of terrestrial and marine OM inputs. Importantly, compound specific isotope analysis of the even numbered n-alkanes would permit identification and tracking of petroleum-derived contaminants. Molecular data alone are ineffective for this, owing to the similarity in CPI values for petroleum-derived contaminants and highly degraded OM which is discharged by the St. Lawrence River into the estuary.

17682. 题目: Soil properties and substrate quality determine the priming of soil organic carbon during vegetation succession
文章编号: N22010918
期刊: Plant and Soil
作者: Youchao Chen, Weipeng Li, Yong You, Chen Ye, Xiao Shu, Quanfa Zhang, Kerong Zhang
更新时间: 2022-01-09
摘要: Purpose There is an increasing recognition that the priming effect (PE) induced by fresh organic matter (FOM) may greatly influence soil organic carbon (SOC) dynamics. However, the patterns of PE induced by substrates with different quality on soils from vegetation succession, as well as the underlying mechanisms, are still unclear. Methods We conducted a field investigation to explore the changes in soil properties and SOC stocks along a secondary vegetation succession (cropland → shrubland → forest); then, we examined the patterns of PE by incubating FOMs with soils from the different succession stages. The added FOMs included 13C-labeled glucose (GLU) as well as labile organic matter (LOM) and recalcitrant organic matter (ROM) extracted from 13C-labeled maize leaves. Results Increases in SOC stock and changes in soil properties were detected during the process of vegetation succession. FOMs with contrasting quality caused PEs in different magnitudes, with a higher PE generated after the GLU and LOM treatments compared with ROM. We also detected a higher soil fungi/bacteria (F/B) with ROM than the GLU and LOM treatment. Under a given substrate treatment, PE was generally higher on cropland soil than shrubland and forest soil. The variations of PE among succession stages were negatively correlated with soil aggregate stability, total inorganic nitrogen, and available phosphorus and positively correlated with pH and F/B ratio. Conclusions Soil properties and substrate quality determine the PE in soils from vegetation succession. The PE might be one of the potential mechanisms underlying soil C dynamics during the vegetation succession.

17683. 题目: Atmospheric oxygen abundance, marine nutrient availability, and organic carbon fluxes to the seafloor
文章编号: N22010917
期刊: Global Biogeochemical Cycles
作者: Devon B. Cole, Kazumi Ozaki, Christopher T. Reinhard
更新时间: 2022-01-09
摘要: The global-scale oxygenation of Earth’s surface represents one of the most fundamental chemical transformations in our planet’s history. There is empirical and theoretical evidence for at least two distinct and stable regimes of Earth surface oxygenation—a ‘low-O2 world’ characterized by pervasively anoxic deep ocean waters, and a ‘high-O2 world’ with dominantly well-oxygenated deep ocean waters represented by our modern surface environment. Numerous biogeochemical processes and feedbacks control the redox state of the marine system, particularly when considered globally and on geologic timescales. It has therefore proven challenging to provide quantitative and internally consistent estimates of the atmospheric oxygen levels (and thereby, productivity, nutrient availability, and reductant consumption) necessary to oxygenate the deep seas. Here, we leverage an Earth-system biogeochemical model that tracks the carbon, nitrogen, oxygen, phosphorus, and sulfur cycles (CANOPS) to provide new quantitative constraints on this relationship. We explore ocean biogeochemistry and fluxes of reduced carbon to the seafloor across a wide range of atmospheric oxygen levels from 0.01 – 100% of the present atmospheric level (PAL), and implement a stochastic approach to provide formal estimates of uncertainty on our results. We find that deep ocean waters remain largely anoxic, and ocean productivity remains significantly muted relative to the modern marine biosphere, until pO2 levels reach ∼40% PAL. These results have major implications for quantitative constraints on atmospheric pO2 levels during the latest Proterozoic and Paleozoic, both in terms of environmental habitability for early animals and with respect to potential energetic constraints on growing and diversifying benthic communities.

17684. 题目: Partitioning the export of distinct biogenic carbon pools in the Northeast Pacific Ocean using a biogeochemical profiling float
文章编号: N22010916
期刊: Global Biogeochemical Cycles
作者: Yibin Huang, Andrea J. Fassbender, Jacqueline S. Long, Sophia Johannessen, Mariana Bernardi Bif
更新时间: 2022-01-09
摘要: We leverage observations from chemical and bio-optical sensors mounted on a biogeochemical profiling float in the Northeast Pacific Ocean to quantify the cycling and export potential of distinct biogenic carbon pools, including particulate inorganic carbon (PIC), particulate organic carbon (POC), and dissolved organic carbon (DOC). Year-round observations reveal complex carbon cycle dynamics among these carbon pools. Net DOC production peaked during bloom initiation, about three months prior to the summer peak in POC production. We validate the float estimates of DOC cycling with seasonal accumulation and removal rates derived from ship-board DOC observations over the same period. By combining chemical and bio-optical tracers of POC cycling, we estimate the instantaneous POC sinking flux (). The co-occurrence of DOC consumption and POC production and sinking during fall and winter resolves the regional conundrum of a persistent particle sinking flux observed by sediment traps during a season that is known to be heterotrophic. PIC production is small, and uncertainties are large. By combining float-based estimates of instantaneous net primary production (NPP) and , we quantify a real-time carbon export ratio ([/ NPP] × 100 %) for the euphotic zone. Elevated export ratios during summer are associated with an increase in the fraction of particles larger than 100 μm in size. Elevated export ratios during winter are associated with the physical redistribution of particles through seasonal deep mixing. Our study demonstrates how the combined use of multiple sensors on biogeochemical profiling floats can provide more nuanced information about upper ocean carbon cycle dynamics.

17685. 题目: The relationships between soil physicochemical properties, bacterial communities and polycyclic aromatic hydrocarbon concentrations in soils proximal to coking plants
文章编号: N22010915
期刊: Environmental Pollution
作者: Jingqi Du, Jinxian Liu, Tong Jia, Baofeng Chai
更新时间: 2022-01-09
摘要: Microbial degradation of polycyclic aromatic hydrocarbons (PAHs) is the major channel for their decontamination from different environments. Aerobic and anaerobic biodegradations of PAHs in batch reactors with single or multiple bacterial strains have been intensively studied, but the cooperative mechanism of functional PAH-degrading populations at the community level under field conditions remains to be explored. We determined the composition of PAH-degrading populations in the bacterial community and PAHs in farmland and wasteland soils contaminated by coking plants using high-throughput sequencing and high-performance liquid chromatography (HPLC), respectively. The results indicated that the PAH content of farmland was significantly lower than that of wasteland, which was attributed to the lower content of low molecular weight (LMW) PAHs and benzo [k]fluoranthene. The soil physicochemical properties were significantly different between farmland and wasteland. The naphthalene content was related to the soil organic carbon (SOC) and pH, while phenanthrene was related to the nitrate nitrogen (NO3−-N) and water content (WC). The pH, SOC, NO3−-N and WC were correlated with the content of high molecular weight (HMW) PAHs and total PAHs. The relative abundances of the phyla Actinobacteria, Chloroflexi, Acidobacteria, and Firmicutes and the genera Nocardioides, Bacillus, Lysobacter, Mycobacterium, Streptomyces, and Steroidobacter in farmland soil were higher than those in wasteland soil. The soil physicochemical characteristics of farmland increased the diversities of the PAH degrader and total bacterial communities, which were significantly negatively related to the total PAHs and LMW PAHs. Subsequently, the connectivity and complexity of the network in farmland were lower than those in wasteland, while the module containing a module hub capable of degrading PAHs was identified in the network of farmland soil. Structural equation modelling (SEM) analysis showed that the soil characteristics and optimized abundance and diversity of the bacterial community in farmland were beneficial for the dissipation efficiency of PAHs.

17686. 题目: Simultaneous adsorption of tetracycline, ammonium and phosphate from wastewater by iron and nitrogen modified biochar: Kinetics, isotherm, thermodynamic and mechanism
文章编号: N22010914
期刊: Chemosphere
作者: Xiumin Li, Jingxin Shi
更新时间: 2022-01-09
摘要: The simultaneous removal of various pollutants in wastewater is increasingly deserved attention. In this study, an efficient adsorbent Fe/N@BC was synthesized by Fe–N co-modification. The adsorbability of Fe/N@BC was evaluated using a mixture with tetracycline (TC), NH4+-N and PO43–P. In comparison to BC, N@BC and Fe@BC, Fe/N@BC exhibited an excellent performance for simultaneously absorbing TC, NH4+-N and PO43–P. The pseudo-first-order was used to describe the adsorption process of NH4+-N and PO43–P, while the pseudo-second-order could be well fitted to TC adsorption data. The adsorption isotherms of TC, NH4+-N and PO43–P were more in line with Sips model (Adj.R2 > 0.97). The maximum adsorption capacities of Fe/N@BC towards TC, NH4+-N and PO43–P were 238.94, 111.87 and 165.02 mg·g−1, respectively, which were 1.31–1.91 times than that of BC, N@BC and Fe@BC. The simultaneous adsorption mechanism mainly involved pore filling, electrostatic interaction, ion exchange, surface complexation, surface precipitation, H bond and π–π interaction. Furthermore, after six cycles, the removal efficiencies of TC, NH4+-N and PO43–P were 75.3, 66.1 and 64.5% by Fe/N@BC, highlighting its promising potential to adsorb multi-pollutants from aqueous solution.

17687. 题目: Addition of walnut shells biochar to alkaline arable soil caused contradictory effects on CO2 and N2O emissions, nutrients availability, and enzymes activity
文章编号: N22010913
期刊: Chemosphere
作者: Tanveer Ali Sial, Sabry M. Shaheen, Zhilong Lan, Punhoon Khan Korai, Imran Ghani, Muhammad Numan Khan, Ainul-Abad Syed, Main Noor Hussain Asghar, Inayatullah Rajpar, Mehrunisa Memon, Saleem Maseeh Bhatti, Hamada Abdelrahman, Esmat F. Ali, Jörg Rinklebe, Jianguo Zhang
更新时间: 2022-01-09
摘要: Mitigation of greenhouse gas (GHGs) emissions and improving soil health using biochar (BC) shall help achieving the UN-Sustainable Development Goals. The impacts of walnut shells biochar (WSB) pyrolyzed at different temperatures on CO2 and N2O emission and soil health have not been yet sufficiently explored. We investigated the effects of addition of WSB pyrolyzed at either 300 °C (WSB-300), 450 °C (WSB-450), or at 600 °C (WSB-600) to alkaline soil on CO2 and N2O emissions, nutrients availability, and soil enzymes activities in a 120-day incubation experiment. Cumulative N2O emissions were reduced significantly as compared to the control, by 64.9%, 50.6%, and 36.4% after WSB-600, WSB-450 and WSB-300, respectively. However, the cumulative CO2 emissions increased, over the control, as follows: WSB-600 (50.7%), WSB-450 (68.6%), and WSB-300 (73.4%). Biochar addition, particularly WSB-600 significantly increased soil pH (from 8.1 to 8.34), soil organic C (SOC; from 8.6 to 22.3 g kg−1), available P (from 21.0 to 60.5 mg kg−1), and K (181.0–480.5 mg kg−1), and activities of urease, alkaline phosphatase, and invertase. However, an opposite pattern was observed with NH4+, NO3−, total N and β-glucosidase activity after WSB application. The WBS produced from high temperature pyrolysis can be used for N2O emissions mitigation and improvement of soil pH, SOC, available P and K, and activities of urease, alkaline, phosphatase. However, WBS produced from low temperature pyrolysis can be used to promote N availability and β-glucosidase; however, these findings should be verified under different field and climatic conditions.

17688. 题目: Development of a novel and efficient biochar produced from pepper stem for effective ibuprofen removal
文章编号: N22010912
期刊: Bioresource Technology
作者: Azri Naima, Fadel Ammar, Ouakouak Abdelkader, Chebbi Rachid, Hecini Lynda, Achmad Syafiuddin, Raj Boopathy
更新时间: 2022-01-09
摘要: A potential biochar from pepper stems (PS-biochar) was developed via a one-stage pyrolysis process of precursor at 700 °C and employed to adsorb ibuprofen (IBP) in water media. Results showed that PS-biochar was a carbonaceous mesoporous adsorbent with well-developed porosity (SBET= 727.5 m2/g and VTotal= 0.36 cm3/g) and rich surface functional groups. Mechanism of IBP adsorption consisted mainly of π- π interaction, pore filling, and H-bonding. The Langmuir monolayer capacity (569.6 mg/g) was very high compared to values reported in similar studies. The successful PS-biochar regeneration after four cycles in the batch system confirmed the high performance of the NaOH (0.1 M) as a desorbing agent. Therefore, the prepared biochar can be considered as a cost-effective and high-performance material for water decontamination.

17689. 题目: Fate of heavy metals and bacterial community composition following biogas slurry application in a single rice cropping system
文章编号: N22010911
期刊: Journal of Soils and Sediments
作者: Qiang Wang, Zhaoming Chen, Jun Zhao, Junwei Ma, Qiaogang Yu, Ping Zou, Hui Lin, Jinchuan Ma
更新时间: 2022-01-09
摘要: Purpose Biogas slurry (BS) is widely used as a valuable fertilizer for crop production. However, little is known about the effects of long-term BS application on potential pollution risk of heavy metals and bacterial community in paddy field. This study aimed to determine the accumulation and rice plant uptake of heavy metals (Cd, Cr, Pb, Cu, and Zn), as well as soil bacterial community composition following repeated BS application in a single rice cropping system. Materials and methods In this study, four treatments were included in a long-term field experiment: CK, no fertilizers; MF, mineral fertilizers, 270 kg urea-N ha–1; and two application rates of BS (BS1, 270 kg N ha–1 and BS2, 540 kg N ha–1). The heavy metals (Cd, Cr, Pb, Cu, and Zn) in soils and rice plants were measured by an inductively coupled plasma mass spectrometer and the soil bacterial community composition was analyzed using Illumina MiSeq sequencing of the 16S rRNA. Results and discussion Soil Zn concentrations were significantly greater in the BS treatments than in the MF treatment. Biogas slurry application significantly increased the heavy metals concentrations in rice plants, compared to the CK treatment. The concentrations of Cd and Pb in grain, and Cu and Zn concentrations in straw were significantly increased by the BS2 treatment compared to the MF treatment, respectively. However, the Cd, Cr, Pb, Cu, and Zn concentrations in grain and soil were all within the safety limits after long-term BS application. Application of BS and of MF resulted in similar bacterial alpha-diversities, and both increased them compared to the CK treatment. Fertilization significantly enhanced the relative abundances of phyla Proteobacteria, Actinobacteria, and Myxococcota but reduced that of Planctomycetota compared to the CK. While, there were no significant differences in those phyla among fertilized treatments. The relative abundances of genera Thiobacillus and Ellin6067 was decreased by the BS2 treatment compared to the MF treatment. Redundancy analysis (RDA) showed that soil organic carbon, available phosphorus and available potassium were the main factors shaping soil bacterial community composition. Spearman’s correlation demonstrated that soil Cd concentration had stronger correlation with some bacterial genera of Bryobacter, Vicinamibacteraceae, and Ellin6067. Conclusions Overall, we conclude that BS application can be considered to substitute mineral fertilizers for rice production. However, the accumulation of heavy metals in paddy soil, especially for Zn, should be considered after long-term BS application.

17690. 题目: Application of machine learning in predicting the adsorption capacity of organic compounds onto biochar and resin
文章编号: N22010910
期刊: Environmental Research
作者: Ying Zhao, Da Fan, Yuelei Li, Fan Yang
更新时间: 2022-01-09
摘要: Detailed prediction of the adsorption amounts of organic pollutants in water is essential to the clean development and management of water resources. In this study, Kriging and polyparameter linear free energy relationship model are coupled to predict adsorption capacity of organic pollutants by biochar and resin. It's based on 1750 adsorption experimental data sets which contains 73 organic compounds on 50 biochars and 30 polymer resins. The Kriging-LFER model shows better accuracy and predictive performance for adsorption (R2 are 0.940 and 0.976) than the published NN-LFER model (R2 are 0.870 and 0.880). Local sensitivity analysis method is adopted to evaluate the influence of each variable on the adsorption coefficient of resin and find out that top sensitive parameters are V and log Ce, to guide parameter optimization. Data's uncertainty analysis is presented by Monte Carlo method. It predicts that the adsorption coefficient will range from 0.062 to 0.189 under the 95% confidence interval. The Kriging-LFER model provides great significance for understanding the importance of various parameters, reducing the number of experiments, adjusting the direction of experimental improvement, and evaluating the fate of organic pollutants in the environment.

17691. 题目: Role and significance of water and acid washing on biochar for regulating methane production from waste activated sludge
文章编号: N22010909
期刊: Science of The Total Environment
作者: Hong-Yu Jin, Zhang-Wei He, Yong-Xiang Ren, Wen-Jing Yang, Cong-Cong Tang, Fan Chen, Ai-Juan Zhou, Wenzong Liu, Bin Liang, Aijie Wang
更新时间: 2022-01-09
摘要: Methane recovered from anaerobic digestion of waste activated sludge (WAS) can be used as the energy supplement of the wastewater treatment plant, and further benefit to its carbon-neutral operation. In order to enhance methane production, biochar (BC) has been widely selected as conductive material to build direct interspecies electron transfer (DIET) in anaerobic digestion of WAS. However, the role and significance of washing strategies, including water and acid washing, on BCs for regulating methane production have not been reported. This study selected the frequently used woody- (W) and straw (S)-BCs as mode. Compared to raw W-BC, water and acid washing W-BC increased the methane yields by 19.1% and 15.7%, respectively. Differently, the methane yields among raw, water and acid washing S-BCs were similar. Mechanism study showed that both the two washing strategies optimized the properties of raw W-BC for promoting methane production. Water and acid washing W-BCs increased the electron transfer functional groups, such as ketones and quinones, which were not observed in S-BCs. Moreover, the electron-active microorganisms were enriched with the presence of water and acid washing W-BCs, and the predominant pathway for methane production shifted from hydrogentrophic to acetotrophic and DIET methanogenesis, while the microbial communities, including bacteria and archaea, were similar with the presence of raw, water and acid washing S-BCs. These findings of this work provide some new insights for production improvement regulation of methane from anaerobic digestion of wastes induced by BCs.

17692. 题目: Transformation of fertilizer nitrogen in fluvo-aquic soils with different textures and its influencing factors
文章编号: N22010908
期刊: Plant and Soil
作者: Shijie Ding, Xiuli Xin, Wenliang Yang, Xianfeng Zhang, Anning Zhu, Shaomin Huang, Jiao Yang, Guocui Ren, Mengrou Li
更新时间: 2022-01-09
摘要: Aims The transformation of the various fractions of soil organic nitrogen (N) plays a pivotal role in soil N retention and in supplying N for crop growth. Soil texture essentially determines the soil’s physical, chemical and biological properties, which affect the soil organic N content and distribution. However, little is known about the incorporation and allocation of fertilizer N among different soil organic N fractions and the fate of fertilizer N in soils with different textures. Methods This study was conducted in a long-term experiment (began in 1990) including three soils of different texture (sandy soil, sandy clay loam and loamy clay) in a winter wheat-summer maize cropping system. A 15N-labelling microplot field experiment was carried out to investigate the distribution and seasonal dynamics of fertilizer N among different soil organic N fractions from October 2017 to May 2018. Results The residual amount of fertilizer N in different textural soils were loamy clay > sandy clay loam > sandy soil. More than 74% of the residual fertilizer N existed in the form of acid hydrolyzable nitrogen (AHN). The levels of hydrolyzable ammonium N (HAN) and hydrolyzable unknown N (UHN) derived from fertilizer decreased gradually during the wheat growing season, and the amino acid-15N (AAN-15N) and amino sugar-15N (ASN-15N) levels decreased first and then increased. The average value of ASN-15N in loamy clay and sandy clay loam was 119% and 58% higher than that in sandy soil; the concentrations of AAN-15N and HAN-15N and the N use efficiency were found to be highest in sandy clay loam. On average, the content of acid insoluble N (NHN) derived from fertilizer in loamy clay was 2.4 and 1.9 times those in sandy soil and sandy clay loam, respectively. The structural equation modeling (SEM) revealed that the different concentrations of dissolved organic nitrogen in the fluvo-aquic soils with different textures directly induced changes in the distribution and seasonal dynamics of fertilizer N in the HAN, ASN and UHN pools, further influencing fertilizer N storage in the soil and supply for wheat. Conclusions Loamy clay had the highest N fertilizer retention capacity of all tested soil types. Sandy clay loam provided more labile fertilizer-derived organic nitrogen and a better environment for roots, thereby increasing the N use efficiency of wheat. The fertilizer N residue in the soils and the fertilizer N supply for wheat were closely related to the concentrations of HAN-15N, ASN-15N and UHN-15N and were affected by the dissolved organic N contents of the soils with different textures.

17693. 题目: Immobilizing chromium in tannery sludge via adding collagen protein waste: an in-depth study on mechanism
文章编号: N22010907
期刊: Environmental Science and Pollution Research
作者: Shuyi Yang, Hongtao Zou, Ying Cheng, E. Tao
更新时间: 2022-01-09
摘要: Owing to containing high fraction of organic matter, the tannery sludge seemed to be fit for composting. Actually, it was intensively harmful to the environment, due to containing chromium (Cr). So it might undergo a long time of storage until finding a proper way to dispose it. In the storage period, it would expose the surrounding environment a risk via releasing Cr. In this study, an approach was proposed to minimize the amount of released Cr, and reveal the mechanism on immobilizing Cr. Collagen protein waste (CPW) was adopted to immobilize Cr, and it was evaluated via leaching experiment. The lowest leaching concentration of Cr was 12 mg/L, meeting the limits of related standard in China (GB 5085.3–2007, Tcr < 15 mg/L). Moreover, the compositions and functional groups of the optimum sample (12 mg/L) were also characterized, confirming that the dominant functional groups cross-linking with Cr were hydroxyl (-OH), carboxyl (-COOH), and epoxy (-COC). Importantly, density functional theory (DFT) calculation was also employed, suggesting that Cr was restrained by accepting electrons from O atoms donating by functional groups.

17694. 题目: Progress in the interaction of dissolved organic matter and microbes (1991–2020): a bibliometric review
文章编号: N22010906
期刊: Environmental Science and Pollution Research
作者: Xuan Yang, Yun Zhang, Qi Liu, Jishu Guo, Qichao Zhou
更新时间: 2022-01-09
摘要: Dissolved organic matter (DOM) and microbes are key in the planetary carbon cycle, and research on them can lead to a better understanding of the global carbon cycle and an improved ability to cope with environmental challenges. Several papers have reviewed one or several aspects of the interaction of DOM and microbes, but no overall review has been performed. Here, we bibliometrically analyzed all publications from the Web of Science on DOM and microbes (1991–2020). The results showed that studies on DOM and microbes grew exponentially during this period; the USA contributed the most to the total publications, and China has had the fastest increasing rate since 2010. Moreover, we used the Latent Dirichlet Allocation model to identify topics and determine their (cold or hot) trends by analyzing the abstracts of 9851 publications related to DOM and microbes. A total of 96 topics were extracted, and these topics that are related to the source, composition, and removal path of DOM and the temporal-spatial patterns of DOM and microbes consistently rose from 1991 to 2020. Most studies have used accurate and rapid methods combined with microbiological genetic approaches to study the interaction of DOM and microbes in terrestrial and aquatic ecosystems. The results also showed that the impacts of climate change and land use on the interaction of DOM and microbes, and topics related to human health have received considerable attention. In the future, the interaction mechanism of DOM and microbes and its response to environmental change should be further elucidated.

17695. 题目: Long-term bare fallow soil reveals the temperature sensitivity of priming effect of the relatively stabilized soil organic matter
文章编号: N22010905
期刊: Plant and Soil
作者: Xiuwei Zhang, Biao Zhu, Fei-Hai Yu, Peng Wang, Weixin Cheng
更新时间: 2022-01-09
摘要: Background and aims Priming effect (PE) plays an important role in modifying the decomposition of soil organic matter (SOM), but large uncertainties remain in the temperature effect on PE mainly due to the variation in SOM stability. Methods We tested the temperature effect on PE of the relatively stabilized SOM by incubating soils collected from a bare fallow (representing the relatively stabilized SOM) and its adjacent old field (containing both stabilized SOM and labile SOM) at 10 and 20 °C for 815 days. We used a natural 13C abundance tracer method for measuring the PE. Results Positive PE was observed in all treatment combinations when maize leaf litter was added. The temperature sensitivity of PE in the bare fallow soil and the old field soil was quite different: increasing temperature significantly enhanced the magnitude of PE in the bare fallow soil, but had no effect on it in the old field soil. The increase of microbial biomass C by litter addition was higher in the bare fallow soil than in the old field soil. Furthermore, for litter-treated soil, temperature increase significantly increased net N mineralization rate throughout the incubation in the bare fallow soil, but had minor effect on it in the old field soil at the end of incubation. Conclusions Overall, this study demonstrates that PE of the relatively stabilized SOM is sensitive to temperature, which may be mainly driven by greater microbial growth and demand for N.

17696. 题目: Ultraviolet-visible and fluorescence spectra indicate the binding and transformation properties of hexavalent chromium in DOM solution
文章编号: N22010904
期刊: Journal of Environmental Chemical Engineering
作者: Situ Mu, Sun Dongxu, Yuxiang Liu, Juan Li, Hongwei Zhang, Jie Wang
更新时间: 2022-01-09
摘要: Dissolved organic matter (DOM) with complex functional groups affects the trace of binding and transformation of hexavalent chromium (Cr(VI)) in the environment. However, the mechanisms and quantitative indicators are still ambiguous. In this study, the perspectives of spectroscopy with synchronous and excitation-emission matrix (EEM) fluorescence, and ultraviolet-visible (UV–vis) were employed to probe the interaction of DOM and Cr(VI). The spectroscopic parameters with Dslope240-280 (the slope of the log-transformed absorbance in the range of 240-280nm), DSlope325-375 (the slope of the log-transformed absorbance in the range of 325-375nm), SR (the ratio of the slope of the log-transformed absorption coefficient with 275-295nm to 350-400nm), SFI (specific fluorescence intensities), AvgFI/AvgUVA (the ratio of average fluorescence to average UV), and SS (Stokes shift) of UV-vis and fluorescence were extracted to characterize the DOM properties. The UV-vis results showed carboxylic-like and total phenolic/carboxylic-like groups were contributed to the complexation of Cr, which resulted in forming macromolecular aggregates, however, the degree of participation of different functional groups was uneven and the binding sequence depended on the types of fractions especially the ratio of protein. Meanwhile, the EEM results proved interaction between DOM and Cr also affected the hydrophobicity and quantum yield of solutions. In addition, according to the change orders of substances and functional groups by Two-dimensional correlation spectroscopy (2DCOS) analysis, aromatic amino acids substances were much more sensitive binding onto Cr than fulvic-like fractions and humic-like fractions, and the mechanisms for Cr(VI) retention were developed. Statistical analysis results showed that SR and SFI were significantly correlated with the concentration of Cr(VI), and multiple linear regression models were developed to predict concentrations of Cr(VI). Moreover, it was found the goodness of fit of SFI was better than that of SR at low Cr concentrations, but opposite at high concentrations.

17697. 题目: Dual roles of Cu2+ complexation with dissolved organic matter on the photodegradation of trace organic pollutants: Triplet- and OH-induced reactions
文章编号: N22010903
期刊: Science of The Total Environment
作者: Huaying Liu, Zhiyu Zhang, Yi-na Tu, Yingjie Li, Yajie Lei, Senlin Tian
更新时间: 2022-01-09
摘要: The triplet excited state of dissolved organic matter (3DOM⁎) is highly effective in the photodegradation of a broad spectrum of trace organic pollutants (TOPs), and its photoactivity is affected by concomitant metal ions in surface waters. However, the impact of environmental metal ions on the 3DOM⁎-induced photodegradation of TOPs has not been systemically explored. Herein, we investigated the effect of environmental Cu2+ on the 3DOM⁎-induced photodegradation kinetics of 16 TOPs. A fluorescence quenching experiment showed that a Cu(II)-DOM complex was formed. For the TOPs with stronger electron-donating groups (triplet-labile moieties, e.g., phenols and anilines), Cu2+ complexation notably inhibited 3DOM⁎-induced photodegradation. This may be ascribed to the decrease of 3DOM⁎ steady-state concentration because Cu2+ complexation reduces its formation rates and enhances scavenging rates tested by sorbic acid isomerization experiment. Meanwhile, it was found that Cu2+ complexation facilitated the photolysis of refractory TOPs (lower triplet reactivity) because of enhanced electron transfer between DOM and Cu(II), causing photoinduced OH formation. These findings implied that 3DOM⁎ reactivity differences in TOPs could affect the photodegradation rates in the complex system, which was confirmed via a linear correlation of photodegradation rate ratios for 16 TOPs induced by 3DOM⁎ in the presence/absence of Cu2+ with their 3DOM⁎ reactivity. These findings helped to improve our understanding of the photochemical reactivity of 3DOM⁎ in natural waters, especially the effects of environmentally concomitant metal ions.

17698. 题目: The dynamic changes of phosphorus availability in straw/biochar-amended soils during the rice growth revealed by a combination of chemical extraction and DGT technique
文章编号: N22010902
期刊: Journal of Soils and Sediments
作者: Caidi Yang, Shenggao Lu
更新时间: 2022-01-09
摘要: Purpose This study compares the dynamic effects of straw and biochar on soil acidity and phosphorus (P) availability in the rice growth period to reveal how straw and biochar affect the availability of phosphorus in soil and utilization of P for rice crop. Materials and methods In the pot experiment, rice straw, canola stalk, and corresponding biochars were mixed uniformly with the Ultisol. Soil samples were collected at four stages of rice growth to analyze the dynamic changes of soil acidity and P availability. The availability of phosphate in straw/biochar-amended soils were evaluated using a combination of chemical extraction and diffusive gradients in thin films (DGT) technique. Results Soil pH, KCl-P, Olsen-P, DGT-P, and Al-P deceased with the rice growth, while Fe-P increased. Biochar increased soil pH and P availability more than straw returning, especially in the mature stage, while the DGT-P only increased in the tillering stage. The DGT-induced fluxes in sediments (DIFS) model revealed that all treatments increased the capacity of soil solid phase supplementing P to pore water in the filling and mature stages. The content of total P in different rice tissues followed the order of grain > straw > root, and RB350 treatment had the highest P content in rice tissues. In the mature stage, soil pH had positive correlations with KCl-P and Olsen-P, and soil Fe-P had positive correlations with total P of root and straw. Conclusions Application of biochar made at 550 ℃ resulted in a larger increase in available P in soil, while biochar made at 350 ℃ had more effect on the chemical forms of P. The canola stalk biochar showed a larger influence on the P availability than rice straw biochar. Biochar treatments had a larger effect on inhibiting soil acidification and improving P availability than straw returning directly.

17699. 题目: Mechanism enhanced active biochar support magnetic nano zero-valent iron for efficient removal of Cr(VI) from simulated polluted water
文章编号: N22010901
期刊: Journal of Environmental Chemical Engineering
作者: Uttam Kumar Sahu, Wenwen Ji, Yuan Liang, Hui Ma, Shengyan Pu
更新时间: 2022-01-09
摘要: This work focused on the use of low-cost magnetic biochar adsorbent prepared from Litchi chinensis peel for the Cr(VI) amelioration through the reduction-adsorption process. This magnetic biochar was prepared by the pyrolysis process, where the nano zerovalent iron (nZVIO) was decorated on the surface of Litchi peel biochar (LPBC). The XRD and TEM studies indicated that the nano-scale zerovalent iron nanoparticles were crystalline having a particle size of 5±0.1nm. The BET analysis showed the mesoporous nature of the material with good surface area (124 m2/g) and also material has a magnetic saturation value of 0.176emu/g, where as surface area of LPBC were 325 m2/g and Ms valie 1.1emu/g respectively. Three factorial Box–Behnken experimental design was simulated for Cr(VI) removal by taking key parameters initial concentration, adsorbent dose, and initial pH as independent factors. The optimum values obtained from desirability function and given by the model were initial Cr(VI) concentration of 5.87mg/L, 3.14 for pH, and 0.195g/L for adsorbent dose, which resulted in approximately 95.38% removal of Cr(VI) in these optimum conditions. Langmuir isotherm and pseudo-second-order kinetics data were explained in the adsorption studies. The adsorbent has an adsorption capacity of 98.36mg/g at the obtained optimized conditions. The thermodynamics study specified a spontaneous process for Cr(VI) removal. The adsorption mechanism was detailed by XPS analysis which indicated a reduction of Cr(VI) to Cr(III) then adsorption of Cr(III) on the adsorbent surface

17700. 题目: Water treatment sludge conversion to biochar as cementitious material in cement composite
文章编号: N22010816
期刊: Journal of Environmental Management
作者: Samuel De Carvalho Gomes, John L. Zhou, Xiaohui Zeng, Guangcheng Long
更新时间: 2022-01-08
摘要: Water treatment sludge was successfully thermally converted to obtain biochar as a stable material with resource potential. This research explored the application of sludge biochar as a supplementary cementitious material. The cement paste samples incorporating different amounts of sludge biochar were prepared, hardened, and analyzed for performance. The results show an improvement in hydration kinetics and mechanical properties of cement paste incorporating biochar, compared to raw sewage sludge. The mineralogical, thermal and microscopic analyses show evidence of pozzolanic activity of the biochar. The samples with 2% and 5% biochar showed higher heat release than the reference material. Specimens with 1%, 2% and 5% biochar showed a slightly higher compressive strength at 28 days compared to the reference material. Sludge conversion to biochar will incur an estimated cost of US$398.23/ton, which is likely to be offset by the substantial benefits from avoiding landfill and saving valuable cementitious materials. Therefore, this research has demonstrated that through conversion to biochar, water treatment sludge can be promoted as a sustainable and alternative cementitious material for cement with minimum environmental impacts, hence contributing to circular economy.