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17661. 题目: Hydrological management affected dissolved organic matter chemistry and organic carbon burial in the Three Gorges Reservoir
文章编号: N21050107
期刊: Water Research
作者: Kai Wang, Yu Pang, Cheng Gao, Long Chen, Xinhao Jiang, Penghui Li, Chen He, Quan Shi, Ding He
更新时间: 2021-05-01
摘要: With the linkage between dissolved organic matter (DOM) and the characteristics of natural ecosystem assessed extensively, the properties of DOM in reservoirs, the typical human interrupted ecosystems, have been focused on in recent years, which is critical for the understanding of human impacts on watershed ecosystems and carbon cycling. This study aims to analyze the effect of hydrological management on the DOM chemistry and organic carbon burial in Daning River tributary of the world's largest Three Gorges Reservoir (TGR). Based on the application of a combined approach including bulk geochemical analyses, optical spectroscopy, and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry, various sources of DOM (terrestrial, anthropogenic, and autochthonous sources) were revealed. An increasing trend of terrestrial and recalcitrant DOM was observed along the upstream to downstream transect of Daning River tributary, which was mainly caused by the water intrusion with a higher terrestrial and recalcitrant signature from mainstream to tributary resulted from hydrological management of TGR. Integrated with the analysis of sedimentary organic matter in Daning River tributary in the past decade (after the construction of TGR), our work suggests that organic carbon burial in the reservoir could be enhanced by hydrological management-induced variation in DOM chemistry. Further studies are needed to better constrain the effects of damming reservoirs on carbon cycling considering their booming all over the world.

17662. 题目: Impact of crop cultivation, nitrogen and fulvic acid on soil fungal community structure in salt-affected alluvial fluvo-aquic soil
文章编号: N21050106
期刊: Plant and Soil
作者: Rongjiang Yao, Jingsong Yang, Wei Zhu, Hongqiang Li, Chunyan Yin, Yupeng Jing, Xiangping Wang, Wenping Xie, Xing Zhang
更新时间: 2021-05-01
摘要: Aims Soil fungal communities play pivotal roles in promoting ecosystem carbon (C) and nitrogen (N) cycling, stimulating disease resistance and enhancing tolerance against salt stress of host plants. However, the impact of anthropogenic management practices on the soil fungal community structure has not yet been clarified. Methods Using a four-consecutive-year field experiment and the quantitative polymerase chain reaction (qPCR) and Illumina MiSeq DNA sequencing methods, the single and interactive impacts of crop cultivation (CK), N fertilization (N) and fulvic acid (F) on soil fungal diversity, abundance, composition and functional groups were investigated. Results Consecutive crop cultivation improved soil chemical and microbial properties by reducing soil electrical conductivity (ECe) and enhancing soil organic carbon (SOC), microbial biomass carbon (MNC), and microbial biomass nitrogen (MBN). Crop cultivation had larger contribution to fungal richness and diversity than N fertilization and fulvic acid. Crop cultivation enriched mycorrhizal fungi and N fertilization enriched endophytic, saprophytic and pathogenic fungi. Structural equation modeling (SEM) revealed that soil ECe and pH indirectly influenced MBN through their adverse direct impact on OTUs, Shannon index and abundance of predominant fungal taxa. N input exhibited a positive indirect influence on MBN through enhancing abundance of Funneliformis at the genus level. Conclusions Crop cultivation, N input, and fulvic acid addition in saline soil environment changed the environmental niches and drove the evolution of soil fungal community. In return, the shifts in soil fungal community composition and functional groups greatly affected soil C and N transformation with potential feedback on soil microbial activity.

17663. 题目: Efficient phosphorus removal by a novel halotolerant fungus Aureobasidium sp. MSP8 and the application potential in saline industrial wastewater treatment
文章编号: N21050105
期刊: Bioresource Technology
作者: Xiaoying Zeng, Jinhui Jeanne Huang, Binbin Hua
更新时间: 2021-05-01
摘要: Efficient halotolerant phosphorus accumulation microorganisms are of great significance for the treatment of high-salt wastewater. In this study, a halotolerant fungus strain named MSP8 was isolated and identified as Aureobasidium sp. Salinity resistance results showed that strain MSP8 can resist the salinity from 0% to 17%, and 77.2% phosphorus removal was achieved at the optimal salinity of 5%. The strain also showed wide environmental adaptability (pH of 3 – 7; temperature of 20 – 30 °C). Batch tests and scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) characterization results verified the key role of extracellular polymeric substance (EPS) secreted by MSP8 in phosphorus removal. The actual brewery and chemical wastewater treatments exhibited that above 53.5% of phosphorus can be removed by MSP8. The excellent adaptation of MSP8 made it a potential candidate for phosphorus removal especially in saline wastewater treatment.

17664. 题目: Efficient adsorption of ciprofloxacin using Ga2S3/S-modified biochar via the high-temperature sulfurization
文章编号: N21050104
期刊: Bioresource Technology
作者: Xiaogang Zheng, Xinyue He, Hao Peng, Jing Wen, Sihao Lv
更新时间: 2021-05-01
摘要: Ga2S3 and sulfur co-modified biochar (Ga/S-BC) composites were prepared for enhancing the adsorption of ciprofloxacin from sugarcane bagasse via the high-temperature sulfurization. In contrast with sulfur-modified biochar, Ga/S-BC exhibited the better adsorption capacity for ciprofloxacin removal. The increasing Ga content induced to the climbing and then declining adsorption activity of Ga/S-BC. Among these obtained Ga/S-BC composites, optimal 3-Ga/S-BC with a Ga content of 7.40% and surface area of 681.67 m2 g-1 exhibited the superior capacity of 330.21 mg g-1. The adsorption capacity of 3-Ga/S-BC declined to 301.66 mg g-1 after nine cycles. pH and inorganic salts also affected the adsorption capacity of 3-Ga/S-BC for ciprofloxacin removal. The adsorption isotherms of obtained Ga/S-BC composites were well described by Langmuir isotherm, and their adsorption kinetics were well estimated via second-order model. The adsorption performance of 3-Ga/S-BC in ciprofloxacin removal was a physisorption and spontaneous process.

17665. 题目: Synergetic effects of biochars and denitrifier on nitrate removal
文章编号: N21050103
期刊: Bioresource Technology
作者: Yuqi Liu, Shulei Liu, Zongcai Yang, Lin Xiao
更新时间: 2021-05-01
摘要: Nitrate is one of the most common water contaminants and has caused severe environmental problems. This work aimed to investigate the effects of integration of denitrifier with biochars on nitrate removal and understand the underlying mechanisms. The results showed that physiochemical properties of biochars varied according to different feedstocks, which influenced bacteria attachment and nitrate removal through adsorption. However, bacteria could colonize on biochars no matter biochars surface were favorable for bacteria attachment or not. Immobilization of denitrifier on biochars significantly improved nitrate removal efficiencies and reduced lag time. Underlying mechanisms investigation showed that the integration of denitrifier with biochars had synergetic effects on promoting nitrate removal, which improved not only the expression and activity of nitrate reductase, but also the electron transport system activity.

17666. 题目: Comparison of the effects of large-grained and nano-sized biochar, ferrihydrite, and complexes thereof on Cd and As in a contaminated soil–plant system
文章编号: N21050102
期刊: Chemosphere
作者: Xiaoxue Ouyang, Jie Ma, Pan Li, Yali Chen, Liping Weng, Yongtao Li
更新时间: 2021-05-01
摘要: Cd and As are difficult to co-remediate in co-contaminated soils. In this study, remediation materials comprising large-grained and nano-sized biochar (BC), ferrihydrite (FH), and complexes thereof were added to Cd- and As-contaminated soil. The uptake of Cd and As by pak choi (Brassica chinensis L.) was then evaluated using a pot experiment and the Cd and As concentrations of the soil pore water and leaching water were measured. The Cd and As concentrations of the pore and leaching water were slightly increased with the addition of BC, and decreased with addition of FH and the biochar–ferrihydrite complex (BC-FH). However, nano-sized BC (BCN), FH (FHN), and BC-FH (BC-FHN) had little influence on the decreases in Cd and As of the two monitored water types. Large-grained remediation materials, rather than nanomaterials, decreased the Cd and As concentrations of the two monitored water types. Nonetheless, nanomaterial treatments more effectively decreased the Cd and As concentrations in plants by an average of >10% relative to the large-grained treatments. The DLVO theory analysis suggest that BCN, FHN, and BC-FHN, immobilized in the topsoil, adsorbed heavy metals in the rhizosphere soil. The remainder of the nano-sized materials was dispersed in the rhizosphere soil pores, shielding the uptake of Cd and As by the roots. Although the doses of nanomaterials used in this study were less than one-fortieth of those of the large-grained materials, changes in the plant rhizosphere microenvironment caused by the nanomaterials decreased the risk of toxicity transfer from the soil to the plants.

17667. 题目: Catalytic steam gasification of food waste using Ni-loaded rice husk derived biochar for hydrogen production
文章编号: N21050101
期刊: Chemosphere
作者: Abid Farooq, Seong-Ho Jang, See Hoon Lee, Sang-Chul Jung, Gwang Hoon Rhee, Byong-Hun Jeon, Young-Kwon Park
更新时间: 2021-05-01
摘要: The disposal of food waste (FW) is a major cause of environmental contamination. This study reports an environmentally friendly FW disposal method in the form of catalytic steam gasification using various types of Ni-loaded chars (untreated char, steam-treated char, and ZnCl2-treated char). The results were also compared with the gasification results from the Ni catalysts supported on commercial α-alumina (Ni/α-Al2O3). The Ni/steam-treated char showed the maximum hydrogen generation (0.471 moles/(g feedstock•g cat)) because of the high reducibility, high nickel dispersion, large amount of inherent K and Ca, and moderate surface area. The overall gas and H2 yield were observed in the following order: Ni/steam-treated char > Ni/ZnCl2 treated char > Ni/untreated char > Ni/α-Al2O3. Brunauer-Emmett-Teller analysis of various catalysts showed that the treated chars have a mesoporous structure, and the X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy – energy dispersive spectroscopy showed that the presence of silica in the chars providing the stable support for the Ni loading and prevented coke formation. The chars obtained from biomass pretreatment could be a potential solution for preventing coke formation at high temperatures, thereby increasing the gas yield and enhancing hydrogen generation.

17668. 题目: Dissolved Organic Carbon in Lakes of the Athabasca Oil Sands Region: Is Color an Indicator of Acid Sensitivity?
文章编号: N21043011
期刊: Environmental Science & Technology
作者: Dane Blanchard, Julian Aherne, Paul Makar
更新时间: 2021-04-30
摘要: The Athabasca oil sands region (AOSR) in north-eastern Alberta, Canada, contains the world’s third largest known bitumen deposit. Oil sands (OS) operations produce emissions known to contribute to acidic and alkaline deposition, which can alter the chemistry of the receiving surface waters, including dissolved organic carbon (DOC). Little is known regarding the natural variability of aquatic DOC among lakes within the AOSR. Surface-water data from 50 lakes were analyzed; variables known to be associated with the light-absorptive properties of DOC (true color [TC]) were evaluated to investigate the potential variability of chromophoric DOC (CDOC). Comparison of TC and DOC revealed two distinct “high” (H) and “low” (L) lake subpopulations, the former being characterized by high relative TC and low DOC, and the latter by the inverse. The H lakes were defined by variables known to be associated with CDOC, while L lakes appeared well-buffered potentially owing to groundwater inputs. The divergent optical properties between subpopulations appeared partially attributable to pH-limited Fe complexation. Trajectory analysis indicated that H lakes most likely to receive atmospheric deposition from OS sources experienced significantly lower pH. These results are contrary to previous studies that found OS emissions to have minimal acidifying effect over lakes throughout the AOSR.

17669. 题目: Organic carbon bioavailability: is it a good driver to choose the best biological nitrogen removal process?
文章编号: N21043010
期刊: Science of The Total Environment
作者: Gabriela Bonassa, Alice Chiapetti Bolsan, Camila Ester Hollas, Bruno Venturin, Daniela Candido, Angélica Chini, Marina C. De Prá, Fabiane Goldschmidt Antes, José Luis Campos, Airton Kunz
更新时间: 2021-04-30
摘要: Organic carbon can affect the biological nitrogen removal process since the Anammox, heterotrophic and denitrifying bacteria have different affinities and feedback in relation to carbon/nitrogen ratio. Therefore, we reviewed the wastewater carbon concentration, its biodegradability and bioavailability to choose the appropriate nitrogen removal process between conventional (nitrification-denitrification) and Anammox-based process (i.e. integrated with the partial nitritation, nitritation, simultaneous partial nitrification and denitrification or partial-denitrification). This review will cover: (i) strategies to choose the best nitrogen removal route according to the wastewater characteristics in relation to the organic matter bioavailability and biodegradability; (ii) strategies to efficiently remove nitrogen and the remaining carbon from effluent in anammox-based process and its operating cost; (iii) an economic analysis to determine the operational costs of two-units Anammox-based process when compared with the commonly applied one-unit Anammox system (partial-nitritation-Anammox). On this review, a list of alternatives are summarized and explained for different nitrogen and biodegradable organic carbon concentrations, which are the main factors to determine the best treatment process, based on operational and economic terms. In summary, it depends on the wastewater carbon biodegradability, which implies in the wastewater treatment cost. Thus, to apply the conventional nitrification/denitrification process a CODb/N ratio higher than 3.5 is required to achieve full nitrogen removal efficiency. For an economic point of view, according to the analysis the minimum CODb/gN for successful nitrogen removal by nitrification/denitrification is 5.8 g. If ratios lower than 3.5 are applied, for successfully higher nitrogen removal rates and the economic feasibility of the treatment, Anammox-based routes can be applied to the wastewater treatment plant.

17670. 题目: Transformations of N derived from straw under long-term conventional and no-tillage soils: A 15N labelling study
文章编号: N21043009
期刊: Science of The Total Environment
作者: Xiu Liu, Wenyi Dong, Shaohui Jia, Qian Liu, Yuzhong Li, Md Elias Hossain, Enke Liu, Yakov Kuzyakov
更新时间: 2021-04-30
摘要: Understanding wheat straw nitrogen (N) transformations in soil depending on tillage practices is necessary to increase the efficient use of straw N and to protect dryland farming environments. Labile organic N pools are crucial for N mineralization but are less investigated because of their fast dynamics. The objectives of this study were to determine the effects of winter wheat straw N (15N-labelled) on soil labile organic N transformations under long-term (27 years) no-tillage and conventional tillage. Four treatments were established under controlled conditions: no-tillage without straw (NoTill); no-tillage with 15N-labelled wheat straw (NoTill+Straw); conventional tillage without straw (ConvTill); and conventional tillage with 15N-labelled straw (ConvTill+Straw). Straw application increased the particulate organic matter N (POMN) and microbial biomass N (MBN) contents, especially in NoTill+Straw, but decreased the dissolved organic N (DON) content. This reflects intensive microbial DON immobilization with the background of plant residues with a high C/N ratio. The 40% to 80% increase in the NH4+ content after straw addition reflects fast straw and soil organic matter (SOM) mineralization, while NO3- declined by 60% to 93% over 56 days, especially in ConvTill soil. 15N recovered in POMN after 14 d was greatest in NoTill+Straw and ConvTill+Straw, reaching 20 and 18 mg 15N kg-1, respectively. Overall, the straw N recovered as NO3- was 72% and 48% greater than that in NH4+ in ConvTill+Straw and NoTill+Straw, respectively, reflecting accelerated SOM mineralization and N mining in the presence of straw. The straw N recovered as POMN was greater through the incubation period (56 days) than that in DON and MBN, especially in NoTill+Straw, indicating that the no-tillage practice reduced straw mineralization. 15N in DON and 15N in NO3- were higher in NoTill+Straw than in ConvTill+Straw, implying that N limitation was alleviated to a certain extent under no-tillage conditions. In conclusion, wheat straw N remained mainly in POMN after 56 days, especially under no-till conditions, and only a minor part was incorporated into DON and microbial biomass. This provides a theoretical basis for straw N use efficiency in agroecosystems.

17671. 题目: Variations in bacterial taxonomic profiles and potential functions in response to the gut transit of earthworms (Eisenia fetida) feeding on cow manure
文章编号: N21043008
期刊: Science of The Total Environment
作者: Ning Wang, Wenhui Wang, Yuji Jiang, Wei Dai, Pengfa Li, Dandan Yao, Jieling Wang, Yu Shi, Zhongli Cui, Hui Cao, Yuanhua Dong, Hui Wang
更新时间: 2021-04-30
摘要: Earthworms play an important role in the organic matter decomposition in terrestrial ecosystems. Earthworms interact directly with the microorganisms to affect the organic matter decomposition via gut transit, i.e., the digestion and assimilation of organic matter in the foregut and midgut and its excretion by the hindgut. However, how the microbial community ingested by earthworms respond to the transit processes in different gut segments of earthworms is not clear. We used composted cow manure to feed earthworms and sampled vermicompost and the contents of foregut, midgut and hindgut for bacterial 16S rRNA gene sequencing analysis. We observed that earthworm gut transit decreased the abundances of the dominant phyla Proteobacteria and Bacteroidetes but increased Actinobacteria, Chloroflexi and Acidobacteria. The alpha diversity of bacterial community in midgut was the lowest of the different gut segments, and the bacterial community structure of the foregut was significantly different from the midgut and hindgut. The enrichment analysis results revealed different selective stimulatory and inhibitory effects on the ingested bacterial community in the different gut segments, which extended to vermicompost. The FAPROTAX data indicated that C and N metabolic microbes were enriched in the earthworm gut. Microbes involved in fermentation and methanogenesis were enriched in the hindgut, and denitrification microbes were enriched in the foregut. The N metabolism microbes in vermicompost were significantly enriched after the stimulation of earthworm gut transit (P < 0.05), and the pathogenic microbes of animals and plants were inhibited. Combined with the results of subsequent correlation and biochemical analyses, earthworm gut transit significantly altered the structure and function of the bacterial community to accelerate the degradation and mineralization of organic matter and the enrichment of phosphorus and potassium. Our study suggests that the gut transit process of earthworms plays an important role in regulating organic matter dynamics in terrestrial ecosystems.

17672. 题目: Diurnal evolutions and sources of water-soluble chromophoric aerosols over Xi'an during haze event, in Northwest China
文章编号: N21043007
期刊: Science of The Total Environment
作者: Qingcai Chen, Xiaoyu Hua, Jinwen Li, Tian Chang, Yuqin Wang
更新时间: 2021-04-30
摘要: Atmospheric brown carbon and their chemical behavior potentially impacts the climate and air quality. Due to lack of researches on the atmospheric chromophores by using online experimental instrument, so using the offline EEM approaches to study their types, sources and chemical processes. In this study, PILS-EEM-TOC system (Particle into liquid sampler coupled with excitation-emission matrix and total organic carbon) was developed in order to distinguish the hourly evolutions and sources of water-soluble chromophoric organic matters in atmospheric fine particles. The results suggested that the sources of atmospheric chromophores in winter were primary combustion (~90%) and coal burning, followed by biomass burning and cooking emissions in Xi'an (Northwest China). These atmospheric chromophores decay under the combined action of solar radiation and atmospheric oxidants. Meanwhile, the secondary chromophores were mainly highly‑oxygenated humic-like substance (HULIS), produced by atmospheric oxidation reactions with the highest peak in the afternoon. The partly secondary chromophores can also be generated through the Maillard-like reaction in the morning, which depends on the relative humidity of the atmosphere. These findings made a deeper understanding of the sources and transformation of atmospheric brown carbon aerosols.

17673. 题目: Roles of sediment supply, geochemical composition and monsoon on organic matter burial along the longitudinal mud belt in the East China Sea in modern times
文章编号: N21043006
期刊: Geochimica et Cosmochimica Acta
作者: Huawei Wang, Selvaraj Kandasamy, Qianqian Liu, Baozhi Lin, Jiann-Yuh Lou, Yoganandan Veeran, Huaiyan Lei, Zhifei Liu, Chen-Tung Arthur Chen
更新时间: 2021-04-30
摘要: Terrestrial sediment supply and its composition, aquatic productivity and coastal hydrodynamics together control the nature of organic matter (OM) that buried in ocean margins. Distinguishing their individual roles in river-dominated continental margins is challenging, but crucial for understanding (i) the regional carbon cycle in modern times and (ii) the OM burial-climate link on shorter timescales. Here we investigate the contents of total organic carbon (TOC) and total nitrogen (TN) and stable carbon isotopic composition of TOC (δ13C), along with grain size and calcium carbonate, in three short, 210Pb- and 137Cs-dated, sediment cores (DH1-1, DH3-3 and DH5-1) from the Yangtze distal mud belt in the East China Sea to delineate the spatiotemporal distribution, origin and burial flux of sedimentary OM for the last ca. 130 years. We also use selected inorganic elements (Si, Al, Ca, Na, K, Rb and Sr) and geochemical proxies derived from them (i.e. chemical index of alteration-CIA, molar Al/Si, molar K/Na, K/Rb and Rb/Sr) to elucidate the importance of detrital composition and chemical weathering on the supply, transport and burial of OM. Bulk organic geochemical and grain size data suggest a longer transport of fine sediments-laden OM, indicating the role of China Coastal Current on hydrodynamic sorting in the study area. Spatial distribution of Al/Si, K/Na, Rb/Sr and CIA in all cores corroborates the selective transport of fine-grained minerals from the Yangtze estuary to the distal mud belt. Less variable molar C/N ratios (5.6–7.7) and δ13C values (–22.4 to –21.2‰) in our cores and the results of δ13C mixing model indicate the predominance of marine OM burial over the last century in the study area. Relationships of TOC, δ13C and mean grain size and spatial evolution of δ13C along the river-mud belt continuum show that adsorption of marine OM on the Yangtze-derived fine sediments during their southward transport. Estimated mean burial fluxes of terrestrial and marine OC (0.73 ± 0.21 and 1.88 ± 0.29 Tg C yr–1) indicate that the Yangtze distal mud belt, despite covering ∼18% of the shelf area, acts as a key OM sequestration center (>50%) in the East China Sea. Comparison of records of riverine OC burial and geochemical weathering and grain size proxies of our cores with East Asian winter monsoon index, and sediment and water discharges in the Yangtze River confirms that hydrodynamics associated with the winter monsoon winds-driven China Coastal Current predominantly controlled the sediment accumulation and OM burial along the mud belt before 1970s. Nonetheless, human activities especially the construction of Three Gorges Dam have reduced the burial flux of terrestrial OC from 0.94 to 0.54 Tg yr–1, significantly affecting the supply and burial of OM and thus the regional carbon cycle since 1970s.

17674. 题目: A small-scale test for rapid assessment of the soil development potential in post-mining soils
文章编号: N21043005
期刊: Soil and Tillage Research
作者: Franziska B. Bucka, Evelin Pihlap, Jara Kaiser, Thomas Baumgartl, Ingrid Kögel-Knabner
更新时间: 2021-04-30
摘要: When ceasing brown coal mining activities, the restoration of the disturbed landscape is required, and a rapid development of functional soils is of utter importance for the rehabilitation of these areas. In order to accelerate soil development and rehabilitation, soils are designed or engineered by applying alternative approaches in order to construct a soil-like substrate, e.g., by mixing different substrates and organic carbon (OC) sources. We used a rapid and easy to perform laboratory approach to simulate the initial steps of soil development. We investigated the mixtures’ properties and the initial development of soil structure, in order to identify suitable soil mixtures for subsequent field trials. We tested six different mixtures composed of increasing complexity, based on the mixture used for a rehabilitation program at a coal mine in southern Australia. The components were overburden, fly ash, paper mulch, brown coal and plant litter. We performed a short-term laboratory incubation in regularly irrigated microcosms for forty days at constant water tension. Our results showed that the addition of fly ash to the overburden led to a higher moisture content. Fly ash together with paper mulch and brown coal improved nutrient supply and OC content, but led also to a very wide C/N ratio >95. The molecular composition of the paper mulch and brown coal OC shows the potential for long-term OC storage because of slow microbial degradation. Microbial activity, as measured by CO2 release, was high in all mixtures with litter addition, but only the additional presence of fly ash, brown coal and paper mulch led to a higher microbial carbon use efficiency (CUE). Soil structure formation, as measured by isolating water-stable aggregates, was induced in all mixtures and intensified in the presence of litter. In the mixtures with litter, there was a predominant formation of large macroaggregates (0.63−30 mm) which stored >80 % of the total OC. We suggest that the complex rehabilitation mixture indicates the potential for soil structure development within a short timeframe also in field scale, because the tested substrates are known to store moisture, deliver nutrients and OC for sustainable microbial growth.

17675. 题目: Critical Impact of Nitrogen Vacancies in Nonradical Carbocatalysis on Nitrogen-Doped Graphitic Biochar
文章编号: N21043004
期刊: Environmental Science & Technology
作者: Zhonghao Wan, Zibo Xu, Yuqing Sun, Mingjing He, Deyi Hou, Xinde Cao, Daniel C.W. Tsang
更新时间: 2021-04-30
摘要: Nitrogen-doped graphitic biochar (NBC) has boosted the development of nonradical peroxymonosulfate (PMS) activation in environmental remediation. However, the specific role of nitrogen species played in NBC-based nonradical carbocatalysis remains vaguely interpreted. To pinpoint the critical nitrogen speciation, a sophisticated thermo-mechanochemical manipulation was exploited to prepare a series of NBCs with similar dimensional structures and oxygen levels but different nitrogen species (i.e., dopants and vacancies). Different from conventional perspectives, nonradical NBC-based carbocatalysis was found to be preferably determined by the nitrogen vacancies more than their parent nitrogen dopants. Raman depth analysis evidenced that a complete transformation of nitrogen dopants into nitrogen vacancies could be achieved at 800 °C, where an excellent nonradical abatement of 4-chlorophenol (4-CH, 90.9% removal) was found for the NBC800 with a low PMS consumption (1.24 mM). According to PMS adsorption experiments, nitrogen vacancies exhibited the highest affinity toward the PMS molecules compared to nitrogen dopants, which accounted for the superior carbocatalysis. Electron paramagnetic resonance and Raman spectroscopic analyses indicated that the original PMS molecules were bound to positively charged nitrogen vacancies, and a robust metastable complex (*HSO5–) evolved subsequently via hydrogen abstraction by adjacent persistent free radicals. In situ Raman techniques could be adopted to estimate the level of nitrogen vacancies associated with the polarization of electron distribution. The flexible feature and practical prospects of nitrogen vacancy-based carbocatalysis were also observed in the remediation of simulated phenolic industrial wastewater. Overall, this study unravels the dilemma in the current NBC-based nonradical carbocatalysis and advances our understanding of nitrogen doping technology for next-generation biochar design.

17676. 题目: Preparation of mesoporous batatas biochar via soft-template method for high efficiency removal of tetracycline
文章编号: N21043003
期刊: Science of The Total Environment
作者: Zhihong Zheng, Baolong Zhao, Yiping Guo, Yujie Guo, Tannaz Pak, Guoting Li
更新时间: 2021-04-30
摘要: In this contribution, we apply a soft-template-assisted hydrothermal route using polyethylene-polypropylene glycol (F127) as soft-template agent and biomass batatas as carbon precursor to synthesis a novel hydrothermal mesoporous biochar (HMC-800) for adsorptive removal of tetracycline (TC) from wastewater. We use the biochar prepared without F127 and direct pyrolytic biochar for comparison. The physicochemical properties of all the studied biochar samples are measured using a suite of characterization techniques. Our results show that the HMC-800 displays the highest specific surface area (286.3 m2/g) and total pore volume (0.249 cm3/g), manifesting the introduction of F127 can result in formation of well-developed pore structures. Regarding adsorption properties, the HMC-800 outperforms other biochar samples for TC removal. Our finding shows that solution with near-neutral pH is favorable for TC removal, and the highest adsorption capacity is observed at initial solution pH value 7. In addition, our findings show that applying the pseudo-second-order kinetic and Freundlich isotherm equation closely models the recorded adsorption behavior. The maximum adsorption capacity is measured to be as much as 238.7 mg/g by Langmuir isotherm model. Pore filling, hydrogen-bonding and n-π interaction are suggested to be the prevailing adsorption mechanisms compared to the other mechanisms. Furthermore, the HMC-800 performs better in regeneration and reuse experiments, making it a promising adsorbent material for TC removal from wastewater.

17677. 题目: Cd immobilization and soil quality under Fe–modified biochar in weakly alkaline soil
文章编号: N21043002
期刊: Chemosphere
作者: Tong Sun, Yingming Xu, Yuebing Sun, Lin Wang, Xuefeng Liang, Shunan Zheng
更新时间: 2021-04-30
摘要: Cost–effective and environment–friendly implementation techniques are critical to the success of remediation in large–scale cadmium (Cd) contaminated agricultural soil. Field experiments were conducted to investigate the effect of Fe–modified biochar on Cd bioavailability in soils and uptake by maize (Zea mays L.), soil aggregate distribution and stability, and microbial community composition in weakly alkaline Cd–contaminated soil. Results showed that Fe–modified biochar optimized the structure and stability of soil aggregates. Moreover, the content of soil organic carbon increased by 6.59%–20.36% when compared with the control groups. However, DTPA–Cd concentration under the treatment of Fe–modified biochar was suffered by 37.74%–41.65% reduction in contrast with CK, and the significant decrease (P < 0.05) was obtained at 0.5% Fe–modified biochar. Moreover, sequential extraction procedures showed that the acid soluble and reducible states of Cd was converted into oxidizable and residual form. The addition of Fe–modified biochar inhibited Cd accumulation in maize, being 41.31%–76.64% (Zhengdan 958), 38.19%–70.95% (Liyu 86) and 52.30%–59.95% (Sanbei 218) reduction, respectively, in contrast with CK. The activity of catalase, urease and alkaline phosphatase in soil increased gradually with the addition of Fe–modified biochar. The enhancement in the number of soil bacterial OTUs and the values of Shannon, Chao1, ACE index indicated that Fe–modified biochar promoted the richness and diversity of bacterial communities. Therefore, the improvements of soil environment and biological quality indicated that Fe–modified biochar should be an alternative agent on remediation of Cd–contaminated soils.

17678. 题目: An integrated method to produce fermented liquid feed and biologically modified biochar as cadmium adsorbents using corn stalks
文章编号: N21043001
期刊: Waste Management
作者: Qi Tao, Bing Li, Yixuan Chen, Junwen Zhao, Qiquan Li, Yulan Chen, Quanhui Peng, Shu Yuan, Huanxiu Li, Rong Huang, Changquan Wang
更新时间: 2021-04-30
摘要: The recycling of agricultural waste is a global challenge to the sustainable development of agriculture. By using corn stalks, we studied the feasibility of combining anaerobic fermentation and pyrolysis processes to produce both fermentated liquid feed and biologically modified biocharas cadmium adsorbents. Anaerobic ensiling enhanced the biodegradation of corn stalks by increasing crude protein and reducing fiber contents. After 24-h anaerobic fermentation, corn stalks silage was decomposed into the liquid filtrate and non-fermented residue. Fermented liquid feed (FLF) was prepared by storing feed and liquid filtrate (1:4.0, wt/wt) in a closed tank at 20 °C for 4 days, which showed desired properties (pH < 4.5, lactic acid bacteria greater than 9.0 lg cfu g−1, lactic acid greater than 100 mmol L-1). The non-fermented residue was pyrolyzed at 500 °C to prepare biologically modified biochar (BCB24). In comparison with pristine biochar produced from corn stalks (CB), anaerobic ensiling and anaerobic fermentation significantly increased the surface area, oxygen-containing functional groups, as well as mineral components in BCB24. The maximum sorption capacity of Cd(II) for BCB24 was 2.1 times of CB, suggesting that BCB24 is an effective adsorbent for Cd(II) removal from water. Our results indicated that coupling anaerobic fermentation and pyrolysis technology can significantly improve the efficiency of corn stalks recycling.

17679. 题目: Synthesis of 13 C-enriched amino acids with 13 C-depleted insoluble organic matter in a formose-type reaction in the early solar system
文章编号: N21042911
期刊: Science Advances
作者: Yoshihiro Furukawa, Yoshinari Iwasa, Yoshito Chikaraishi
更新时间: 2021-04-29
摘要: Solvent-soluble organic matter (SOM) in meteorites, which includes life’s building molecules, is suspected to originate from the cold region of the early solar system, on the basis of 13 C enrichment in the molecules. Here, we demonstrate that the isotopic characteristics are reproducible in amino acid synthesis associated with a formose-type reaction in a heated aqueous solution. Both thermochemically driven formose-type reaction and photochemically driven formose-type reaction likely occurred in asteroids and ice-dust grains in the early solar system. Thus, the present results suggest that the formation of 13 C-enriched SOM was not specific to the cold outer protosolar disk or the molecular cloud but occurred more widely in the early solar system.

17680. 题目: Multiple carbon incorporation strategies support microbial survival in cold subseafloor crustal fluids
文章编号: N21042910
期刊: Science Advances
作者: Elizabeth Trembath-Reichert, Sunita R. Shah Walter, Marc Alec Fontánez Ortiz, Patrick D. Carter, Peter R. Girguis, Julie A. Huber
更新时间: 2021-04-29
摘要: Biogeochemical processes occurring in fluids that permeate oceanic crust make measurable contributions to the marine carbon cycle, but quantitative assessments of microbial impacts on this vast, subsurface carbon pool are lacking. We provide bulk and single-cell estimates of microbial biomass production from carbon and nitrogen substrates in cool, oxic basement fluids from the western flank of the Mid-Atlantic Ridge. The wide range in carbon and nitrogen incorporation rates indicates a microbial community well poised for dynamic conditions, potentially anabolizing carbon and nitrogen at rates ranging from those observed in subsurface sediments to those found in on-axis hydrothermal vent environments. Bicarbonate incorporation rates were highest where fluids are most isolated from recharging bottom seawater, suggesting that anabolism of inorganic carbon may be a potential strategy for supplementing the ancient and recalcitrant dissolved organic carbon that is prevalent in the globally distributed subseafloor crustal environment.