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所有论文

17481. 题目: Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland
文章编号: N19090414
期刊: Global Change Biology
作者: Juan Jia, Zhenjiao Cao, Chengzhu Liu, Zhenhua Zhang, Li Lin, Yiyun Wang, Negar Haghipour, Lukas Wacker, Hongyan Bao, Thorston Dittmar, Myrna J. Simpson, Huan Yang, Thomas W. Crowther, Timothy I. Eglinton, Jin‐Sheng He, Xiaojuan Feng
更新时间: 2019-09-04
摘要: Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized (14C‐enriched) carbon in the subsoil slow‐cycling pool (silt‐clay fraction) but promoted the decomposition of plant‐derived lignin in the fast‐cycling pool (macroaggregates). These changes mirrored an accumulation of lipids and sugars at the expense of lignin in the warmed bulk subsoil, likely associated with shortened soil freezing period and a deepening root system. As warming is accompanied by deepening roots in a wide range of ecosystems, root‐driven accrual of slow‐cycling pool may represent an important and overlooked mechanism for a potential long‐term carbon sink at depth. Moreover, given the contrasting sensitivity of SOC dynamics at varied depths, warming studies focusing only on surface soils may vastly misrepresent shifts in ecosystem carbon storage under climate change.

17482. 题目: Use of fatty acids as tracer of organic matter input associated with level of land urbanization
文章编号: N19090413
期刊: Environmental Science and Pollution Research
作者: Angela Ethelis Jiménez Martínez, Aluana Schleder, Juan Sanez, Anelize Bahniuk, Sandro Froehner
更新时间: 2019-09-04
摘要: Suspended sediments (SSs) were examined regarding the content of fatty acids (FAs) to associate them with sources of soil entry into the river. The source of organic matter was traced through fatty acid distribution, as well as erosion. Also, TOC, TN, and TOC/NT were used to support the results of FAs. For this, a tropical river was chosen to understand the main source of input considering the level of land occupation along the river. The Barigui river, in southern Brazil, was segmented in four distinct areas regarding the soil occupation (P1, P2, P3, and P4). Nine sampling campaigns were conducted from Nov/2014 to Nov/2015 using a time-integrated sampler. Site P1 has the lowest level of urbanization and showed the lowest concentration of FAs (16.35 μg−1). In contrast, site P4, the most urbanized, showed the highest content of fatty acids, including those associated with erosion, 378.53 μg g−1, specifically those with long chains. The mean concentrations of the saturated fatty acids (FAs) was 283.40 μg g−1, monounsaturated fatty acids (MUFAs) was 79.46 μg g−1, and polyunsaturated fatty acids (PUFAs) was 15.66 μg g−1. Twenty-seven fatty acids were examined, nevertheless C15:0, C16:0, C18:0, and C18:1ω9 prevailed in all samples. Generally, those acids indicate sewage inputs. Statics analyses were used to find the relation between the source of organic matter (autochthonous, allochthones, and anthropogenic) and FAs. Finally, the input of organic matter is associated with land occupation, which can be distinguished by FA distribution.

17483. 题目: Effect of humic acid on the sedimentation and transport of nanoparticles silica in water-saturated porous media
文章编号: N19090412
期刊: Journal of Soils and Sediments
作者: Mo Zhang, Duo Li, Zhi Ye, Shiqi Wang, Nan Xu, Fang Wang, Shouqing Liu, Jianping Chen, Huajie Gu
更新时间: 2019-09-04
摘要: Purpose: Nano silicon particles (nSiO2) is one of the most widely used industrial engineered nanomaterials (ENMs). The extensive applications of nSiO2 may pose potential risks to aquatic ecosystems and human health. Humic acid (HA) is a major component of soil and water that exists widely in the natural environment and adsorbs to the surface of nanoparticles, which affects the fate and transport of ENMs in soil. Therefore, it triggers the necessity to study the chemical reaction of HA controlling the sedimentation and transport of nSiO2. Materials and methods: The sedimentation kinetics and transport breakthrough curves of nSiO2 with/without HA in water-saturated porous media were studied in two electrolyte (NaCl and CaCl2) solutions. The likely mechanisms were explored with both multiple technologies and numerical modeling including TEM-EDX, particle size distribution, zeta potentials, and the two-site kinetic attachment model (TSKAM). Results and discussion: Our experimental results showed that the existence of HA generally increased the suspensivity and the transportability of nSiO2 in NaCl and CaCl2 solutions in packed sand columns at acidic pH. This result was attributed to the HA adsorption leading to the more negatively charged surface and the smaller size of nSiO2 aggregates. However, the formation of coordination complexes associated with larger cluster among nSiO2 between HA and Ca2+ contributed to the increased sedimentation of nSiO2 at alkaline pH. Subsequently, the presence of HA inhibited the transport of nSiO2 in CaCl2 solution at pH 9.0. Comparably, in NaCl at pH 9.0, HA showed the negligible effect on the nSiO2 deposition in sand. Both the attachment and detachment parameters, which were obtained from fitting the breakthrough curves of ENMs using the TSKAM, could be used to well describe the transport behavior of nSiO2 with HA under various conditions. In particular, the irreversible attachment parameters at site 2 on sand were positively related to the retention of nSiO2 with HA. Conclusions: The fate and transport of nSiO2 can be distinctly affected by HA depending on the ion composition, ion strength, and pH in soil. This study will provide insights for assessing the mobility of nSiO2 with HA in subsurface soil and aquatic environments.

17484. 题目: Differential responses of soil N2O to biochar depend on the predominant microbial pathway
文章编号: N19090411
期刊: Applied Soil Ecology
作者: Cheng Ji, Shuqing Li, Yajun Geng, Yingcheng Miao, Ying Ding, Shuwei Liu, Jianwen Zou
更新时间: 2019-09-04
摘要: Biochar amendment has been proposed as a potential strategy to reduce soil nitrous oxide (N2O) emissions, although experimental studies have generated inconsistent results on N2O emissions following biochar amendment. Differential responses of soil N2O to biochar amendment may depend on soil microbial functional genes abundance and abiotic properties. Here we sampled three types of soil from fields under long-term cultivation of green tea (TG), film greenhouse vegetable cabbage (GV) and Jerusalem artichoke (JA), respectively. We conducted a microcosm experiment to examine N2O emissions from the different soils following biochar amendment. Results showed that biochar amendment increased N2O emissions from the GV soil while decreasing N2O emissions from the TG and JA soils in the presence of nitrogen fertilizer. Biochar amendment increased soil pH and C/N ratio across the three soils. Quantitative PCR (qPCR) analysis showed that biochar amendment also consistently increased the abundances of AOB and nosZ genes but decreased the AOA abundances for all the soils, while the effects of biochar on the abundances of nirK and nirS genes differed between the soils. Our results suggest that biochar amendment can affect the processes of both ammonia oxidation and reduction of N2O to N2 for all the soils and the net effect of biochar on N2O emissions depended on the predominant process in a specific soil. Biochar-induced increase in N2O emissions in the GV soil was largely attributed to the stimulated nitrification rate, which was primarily driven by AOB. Biochar-induced decreases in N2O emissions in the TG and JA soils were linked to the increased nosZ gene abundances. Overall, the effectiveness of biochar for mitigating N2O emissions is linked to its dominant N2O production pathway in soils.

17485. 题目: Activation of persulfate with biochar for degradation of bisphenol A in soil
文章编号: N19090410
期刊: Chemical Engineering Journal
作者: Junguang Liu, Shaojun Jiang, Dongdong Chen, Guangling Dai, Dongyang Wei, Yuehong Shu
更新时间: 2019-09-04
摘要: In this study, a new alternative activator, biochar (BC) pyrolyzed by waste biomass—lychee branch, was applied in persulfate (PS) -based remediation for bisphenol A (BPA) in soils. Radical species, solution pH, dose of PS and BC were studied to evaluate the performance of PS activation by BC to degrade BPA in aqueous solution. The results show that BC can efficiently activate PS to generate sulfate radicals and hydroxyl radicals to degrade BPA high efficiently. The increase of PS and BC dosage can increase BPA removal rate, and a lower pH is benefit for the BPA degradation in aqueous solution. In addition, the degradation intermediates of BPA were characterized and the degradation pathways were proposed. Furthermore, the PS/BC system is most efficient for BPA degradation compared with other oxidants. For soil spiked with 31.93 mg kg−1 BPA, BC can also activate PS and degrade BPA effectively. The increase of BC and PS dose cannot always increase BPA degradation because of the competition of readily oxidizable matter introduced by BC itself and/or quenching of sulfate radicals. During BPA degradation in soil, the pH value drops less than those in literatures on PS oxidation of organic contaminants in soil by other activation methods, which can alleviate soil acidification in the remediation process. The results of this study suggest a novel technique for potential application in in-situ remediation of organic contaminated sites.
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17486. 题目: New advances in fluorescence excitation-emission matrix spectroscopy for the characterization of dissolved organic matter in drinking water treatment: A review
文章编号: N19090409
期刊: Chemical Engineering Journal
作者: Lei Li, Yang Wang, Wenjun Zhang, Shuili Yu, Xianyun Wang, Naiyun Gao
更新时间: 2019-09-04
摘要: Fluorescence technology has been increasingly applied in dissolved organic matter (DOM) characterization due to its remarkable sensitivity and selectivity. Interest in using fluorescence technology to investigate drinking water treatment with a focus on coagulation, adsorption, membrane filtration and disinfection is growing. Fluorescence excitation-emission matrix (EEM) spectroscopy, also known as three-dimensional fluorescence (3D-EEM) or fluorescence fingerprinting, is one of the most predominant approaches because of the massive amount of data, visual maps and multidimensional information it provides. Various EEM map interpretation methods have been developed. This paper reviews current predominant 3D-EEM interpretation methods (ranging from basic methods, peak picking and fluorescence regional integration (FRI) to chemometric methods) and summarizes the latest findings and problems related to practical applications. The correlations between optical and physicochemical properties, such as molecular weight and hydrophilic-hydrophobic properties, are investigated. Novel findings on drinking water trains obtained with the assistance of these interpretation methods are discussed and broadly classified as follows: a) evaluating water treatment performance, b) observing DOM behavior, c) monitoring and predicting micropollutants and disinfection byproducts (DBPs). The importance of using artificial intelligence in fluorescence technology and developing advanced real-time sensors, the weaknesses of fluorescence spectroscopy and the need for combination with other technologies (e.g., fractionation techniques) are highlighted.

17487. 题目: Surface-modified spherical lignin particles with superior Cr(VI) removal efficiency
文章编号: N19090408
期刊: Chemosphere
作者: Hyo Won Kwak, Hyunji Lee, Ki Hoon Lee
更新时间: 2019-09-04
摘要: Lignin, natural aromatic polymer derived from plant dry matter, is second abundant biopolymer. Recently, interest in applications of lignin, especially as an adsorbent material is increasing. However, the physicochemical complexity of lignin significantly reduces access to practical environmental remediation processes. Also, there is a limitation because the adsorption performance of the pristine lignin materials is not superior to that of commercial adsorbent and ion exchange resin material. In this study, spherical lignin particles with high physicochemical stability and excellent Cr(VI) adsorption capacity are prepared using a polyethylenimine (PEI) modification strategy. This modification process significantly improves the mechanical properties and water stability of lignin by complementing the instability of lignin particles. In addition, the PEI-lignin particles exhibit a superior Cr(VI) removal capability (657.9 mg/g, the highest value for a PEI-modified natural adsorbent), which is attributed to their structural stability and introduced amine functional groups. The Cr(VI) removal with PEI-lignin particles is performed via intra-particle diffusion and adsorption followed by covalent bonding combined with a reduction process. Moreover, the PEI-lignin particles exhibit excellent reusability, which sustains their high adsorption efficiency over a long and repeated adsorption period. The results herein strongly support the potential use of PEI-lignin particles as a high performance bio-sorption material for heavy metal removal and its detoxification in aqueous wastewater streams. Evidently, this lignin-based bio-sorbent manufacturing system can provide sustainable bio-resource recycling and cost efficiency.
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17488. 题目: Fast photocatalytic inactivation of Microcystis aeruginosa by metal-organic frameworks under visible light
文章编号: N19090407
期刊: Chemosphere
作者: Gongduan Fan, Jinjin Zhou, Xiaomei Zheng, Jing Luo, Liang Hong, Fangshu Qu
更新时间: 2019-09-04
摘要: In this work, Metal-organic Frameworks (MOFs) were applied to inactivate algae under visible light with low doses. Five MOFs with different compositions (Zn and Fe; carboxylates or imidazolates) were successfully synthesized and characterized by XRD, SEM and UV–vis. The effects of MOFs on Microcystis aeruginosa were evaluated with regard to morphology characteristics, physiological activity, cell integrity and pigment degradation. The results indicated that Ag/AgCl@ZIF-8 outperformed MOF-235, ZIF-8, Bi2WO6/MIL-100(Fe) and BiOBr/MOF-5 in the degradation of chlorophyll a at the dose of 10 mg L−1. After 6 h of irradiation, 93.1% of Microcystis aeruginosa died and was unable to regrow and reproduce, which was demonstrated by changes in cell morphology, damage of cell membrane integrity and antioxidant enzyme system. Besides, the intracellular organic matter (IOM) and extracellular organic matter (EOM) were proven to be efficiently removed by MOF-assisted photocatalytic inactivation. Superoxide radical (O2·-) was demonstrated to be the major reactive oxygen species. A probable mechanism was proposed that the electrons in the valence band of Ag/AgCl@ZIF-8 transfer into the conduction band under irradiation to produce O2·- which inactivated the algae cells. Furthermore, Ag/AgCl@ZIF-8 can effectively remove Microcystis aeruginosa under sunlight and is of great application prospects for algae removal in real water bodies.
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17489. 题目: Mechanisms of U(VI) removal by biochar derived from Ficus microcarpa aerial root: A comparison between raw and modified biochar
文章编号: N19090406
期刊: Science of The Total Environment
作者: Nuo Li, Meiling Yin, Daniel C.W. Tsang, Shitong Yang, Juan Liu, Xue Li, Gang Song, Jin Wang
更新时间: 2019-09-04
摘要: Uranium (U) is a toxic and radioactive element. Excessive amounts of aqueous U(VI) generated from U mining, processing and nuclear industry may result in severe and irreversible damage to the environment. Herein, Ficus microcarpa aerial root (FMAR), a biowaste material, was used to adsorb U(VI) from aqueous solutions for the first time. Potassium permanganate (KMnO4)-modified FMAR biochar was synthesised, characterised and compared with raw (unmodified) biochar with respect to U(VI) adsorption. The results showed that the adsorption capability of the modified FMAR biochar was evidently higher than that of the raw biochar. Multiple characterisation techniques confirmed that the discrepancy was mainly due to the increased content of O−H and formation of irregular sheet-like nanostructure with the ultrafine MnO2 nanoparticles on the biochar surfaces after KMnO4 modification. The abundance of O−H and nanoscale MnO2 notably enhanced the adsorption of U(VI) by means of coordination and Lewis acid-base interaction. The results indicate that KMnO4-modified FMAR biochar has a good potential to serve as an environment-friendly adsorbent for the removal of U(VI) from solution.
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17490. 题目: A novel enhanced anaerobic biodegradation method using biochar and Fe(OH)3@biochar for the removal of nitrogen heterocyclic compounds from coal gasification wastewater
文章编号: N19090405
期刊: Science of The Total Environment
作者: Jingxin Shi, Hongjun Han, Chunyan Xu
更新时间: 2019-09-04
摘要: Three identical lab-scale sequencing batch reactors (SBR) were operated for 120 days for raw (R1), biochar (R2), and Fe(OH)3@biochar (R3) enhanced anaerobic degradation of selected nitrogen heterocyclic compounds (NHCs). The occurrence of Fe-OH ensured the successful attachment of Fe(OH)3 to biochar as evidenced by the Fourier transform infrared (FTIR) spectra of biochar and Fe(OH)3@biochar. Acute biotoxicity experiments revealed that enhancing biochar and Fe(OH)3@biochar effectively decreased the toxicity of microorganisms. Additionally, the introduction of biochar and Fe(OH)3@biochar improved the settling performance of anaerobic sludge. Further, it was concluded that enriched Longilinea and Comamonas might be the major genera that function to degrade selected NHCs in anaerobic conditions.
图文摘要:

17491. 题目: Occurrence and transport behaviors of perfluoroalkyl acids in drinking water distribution systems
文章编号: N19090404
期刊: Science of The Total Environment
作者: Ruya Chen, Guiwei Li, Ying Yu, Xu Ma, Yuan Zhuang, Hui Tao, Baoyou Shi
更新时间: 2019-09-04
摘要: Although human exposure to perfluoroalkyl acids (PFAAs) through tap water is an ongoing concern, knowledge of the PFAAs occurrence in the tap water and the associated transport behaviors of PFAAs in drinking water distribution systems (DWDSs) are scarce. This investigation profiled the occurrence of 17 kinds of PFAAs in tap water of some Chinese cities, and the transport behaviors of PFAAs in DWDS were observed in eastern China. Tap water samples both along trunk pipelines and at the distal ends were collected to display the PFAAs occurrence scenarios. Loose deposit solids were also obtained to reveal their possible accumulation effect on PFAAs. The results showed that perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) widely existed in tap water samples, and were the predominant PFAAs in eastern China areas. The mean concentration of the 17 PFAAs was 77.49 ng/L (ranging from 9.29 ng/L to 266.68 ng/L). Short-chain PFAAs (mainly PFBA) concentrations were relatively stable from water treatment plant to consumer taps, while long-chain PFAAs (mainly PFOA) exhibited a significant decrease in concentration, which could be attributed to their accumulation by the loose deposits in the DWDSs. It was calculated that PFOA has a higher partition coefficient than PFBA; this means that the former has a stronger potential to be adsorbed by loose deposits. In addition, the accumulation ability of loose deposits might be associated with the composition of Al, Fe and Si in the loose deposits. The positive correlation between the short-chain PFAAs and dissolved organic carbon (DOC) indicated the possible interactions between PFAA and natural organic matter could favor short-chain PFAAs to retain in bulk water. When water quality conditions change or hydraulic disturbance occur, loose deposits may enter tap water bringing accumulated PFAAs with it, which may result in potential health risks.
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17492. 题目: Degradation of nitrogen-containing refractory organic wastewater using a novel alternating-anode electrochemical system
文章编号: N19090403
期刊: Science of The Total Environment
作者: Yang Deng, Nan Chen, Chuanping Feng, Haishuang Wang, Yuhan Zheng, Fangxin Chen, Wang Lu, Peijing Kuang, Hanguang Feng, Yu Gao, Weiwu Hu
更新时间: 2019-09-04
摘要: This study presented a novel alternating-anode electrochemical system (AAES) based on single electrolytic cell for the treatment of nitrogen-containing refractory organic wastewater (NOW). The core of AAES lies in the alternating working of iron anode and DSA anode to integrate different electrochemical processes. The biologically treated landfill leachate (BTLL) was selected as a practical NOW for assessing the performance of AAES. The results indicated that after 140 min of electrolytic reaction, the removal efficiency of chemical oxygen demand and total nitrogen (TN) using AAES was found to be 76.9 and 98.9%, respectively. The main component of dissolved organic matter (DOM) in BTLL included humic-like substances, which could be degraded into small-molecule DOM, such as fulvic-like substances and protein-like substances, by available chlorine and hydroxyl radicals present in AAES. Cathode reduction (NOx-N → NH4+–N and N2) under iron anode and indirect oxidation (NH4+–N → N2) under DSA anode were the main pathways to remove TN from NOW. Owing to the redox conditions created by the alternating anodes, the main stable crystalline forms of precipitates obtained from AAES were Fe3O4 and γ-Fe2O3, which could be separated by using the external magnetic field. The findings of this study may provide a feasible solution for the advanced electrochemical treatment of NOW in a single electrolytic cell as well as rapid separation of precipitates.
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17493. 题目: Improved chlorine and chromium ion removal from leather processing wastewater by biocharcoal-based capacitive deionization
文章编号: N19090402
期刊: Separation and Purification Technology
作者: Zhaoyang Du, Weijun Tian, Kaili Qiao, Jing Zhao, Liang Wang, Wenlong Xie, Meile Chu, Tiantian Song
更新时间: 2019-09-04
摘要: Red oak biocharcoal, a novel electrode material that is inexpensive and highly conductive, was used for capacitive deionization (CDI) to simultaneously remove Cl- and Cr3+ from leather processing wastewater. The results showed that both the carbonization temperature and time played important roles in reducing the resistivity (ρ) of biocharcoal. Additionally, at 1000 °C and 3 h, the ρ value was reduced from 4.68 to 1.19 Ω·cm after the addition of Fe2O3. KOH impregnation enhanced the desalination capacity of the biocharcoal electrodes by increasing the specific surface area and hydrophilicity. Under the optimal operating parameters (voltage of 1.8 V, flow rate of 10 ml/min and electrode spacing of 2 mm), the KOBC15 electrode exhibited a maximum adsorption capacity of 13.79 mg/g. After 10 cycles of CDI system operation, the removal rates of Cl- and Cr3+ reached 86.7% and 100%, respectively, in simulated leather processing wastewater. This work provides new ideas and methods for the treatment of high-salinity wastewater.
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17494. 题目: Fungal laccase-mediated humification of estrogens in aquatic ecosystems
文章编号: N19090401
期刊: Water Research
作者: Mingyu Chen, Michael Gatheru Waigi, Shunyao Li, Kai Sun, Youbin Si
更新时间: 2019-09-04
摘要: Estrogens are a category of non-degradable organic pollutants prevalent in aquatic environments with reported health risks in human and wildlife reproduction. A biotechnological approach is proposed for utilizing fungal laccase-mediated humification reactions (L-MHRs) to remove estrogens from water. Through a reactive radical-mediated C–C, C–O–C, or C–N–C covalent coupling mechanism, multifarious complex polymeric structures are generated having limited solubilities, which significantly reduces their estrogenic activity and ecotoxicity. This review highlights the available literature associated with the self/cross-coupling mechanism of fungal L-MHRs in catalyzing the single-electron oxidation of estrogens and humic acid (HA). Advances in identifying unknown estrogen-HA cross-coupling products using high-resolution mass spectrometry combined with 13C-isotope labeling and 13C NMR may provide key research directions beneficial to aquatic ecological restoration measures.
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17495. 题目: Unique Neoproterozoic carbon isotope excursions sustained by coupled evaporite dissolution and pyrite burial
文章编号: N19090310
期刊: Nature Geoscience
作者: Graham A. Shields, Benjamin J. W. Mills, Maoyan Zhu, Timothy D. Raub, Stuart J. Daines, Timothy M. Lenton
更新时间: 2019-09-03
摘要: The Neoproterozoic era witnessed a succession of biological innovations that culminated in diverse animal body plans and behaviours during the Ediacaran–Cambrian radiations. Intriguingly, this interval is also marked by perturbations to the global carbon cycle, as evidenced by extreme fluctuations in climate and carbon isotopes. The Neoproterozoic isotope record has defied parsimonious explanation because sustained 12C-enrichment (low δ13C) in seawater seems to imply that substantially more oxygen was consumed by organic carbon oxidation than could possibly have been available. We propose a solution to this problem, in which carbon and oxygen cycles can maintain dynamic equilibrium during negative δ13C excursions when surplus oxidant is generated through bacterial reduction of sulfate that originates from evaporite weathering. Coupling of evaporite dissolution with pyrite burial drives a positive feedback loop whereby net oxidation of marine organic carbon can sustain greenhouse forcing of chemical weathering, nutrient input and ocean margin euxinia. Our proposed framework is particularly applicable to the late Ediacaran 'Shuram' isotope excursion that directly preceded the emergence of energetic metazoan metabolisms during the Ediacaran–Cambrian transition. Here we show that non-steady-state sulfate dynamics contributed to climate change, episodic ocean oxygenation and opportunistic radiations of aerobic life during the Neoproterozoic era.

17496. 题目: The impact of biochar on soil carbon sequestration: Meta-analytical approach to evaluating environmental and economic advantages
文章编号: N19090309
期刊: Journal of Environmental Management
作者: Supriya Majumder, Surama Neogi, Tanushree Dutta, Michael A. Powel, Pabitra Banik
更新时间: 2019-09-03
摘要: Soil carbon (SC) is important for food security, ecosystem functioning, and environmental health, especially in light of global climate change. The physico-chemical character of biochar (pyrolyzed crop residue) has been shown to augment SC levels. This review systematically compares the environmental and economic benefits of applying crop residue versus biochar produced from crop residues to soils and the potential implications for SC sequestration. Crop residues enhance the mineralization rate of SC, while biochar can increase or decrease SC depending on the types of biochar/soil and duration. Therefore, converting crop residues to biochar may be more efficient for sequestering SC, but may/may not be more cost-effective. In this review, special emphasis is given to understanding the underlying mechanisms and biogeochemical processes of biochar production, in particular: surface (crystallinity), redox, and ability to control electron transfer reactions. By using meta-analytics, we determined the role of biochar compared to crop residue to enhance the status of organic SC.
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17497. 题目: Biochar slows gross nitrification and gasses N emission via lower autotrophic nitrification in paddy soils
文章编号: N19090308
期刊: Journal of Soils and Sediments
作者: Fayong Li, Xinqiang Liang, Shuang He, Meiru Li, Yucheng Cao, Jin Zhang, Guangming Tian
更新时间: 2019-09-03
摘要: Purpose: Laboratory incubation experiments using 15N stable isotope labeling and acetylene suppression techniques were conducted to compare the autotrophic nitrification and heterotrophic nitrification rates with the addition of swine manure (SW) and swine-manure-derived biochar (SWB) in two paddy soils. Materials and methods: SW and SWB were applied at four N-based amendment levels, namely control (0 mg N kg−1), low (1.1 mg N kg−1), medium (2.2 mg N kg−1), and high (4.4 mg N kg−1). Twenty-five milliliters of C2H2 gas were injected into each storage bottle to inhibit autotrophic nitrification in soil. At the end of the preincubation period, 160 mg kg−1 15N-glycine were added to each storage bottle to stimulate heterotrophic nitrification in soil. Results and discussion: Results showed that SW increased the NH4+-N content by 3.5 to 17.5 mg kg−1 in both soils, while SWB decreased it by 0.1 to 4.7 mg kg−1 compared to control group, regardless of whether autotrophic nitrification was inhibited. Both SW and SWB enhanced NO3-N accumulation in the two soils compared to control group when autotrophic nitrification was not inhibited; however, NO3-N concentration in the soil with SWB was up to 24% lower than that with the same level of SW addition. NH3 volatilization rates were elevated at all the SW and SWB amendment levels, although only SW led to higher N2O emission rates. Compared with SW, high level of SWB significantly decreased N2O emissions by 78 to 84% in the loam and clay loam soils. The increase in NH3 volatilization, soil NO3-N accumulation, and autotrophic nitrification rate were greater with SW than with SWB. Higher rates of soil heterotrophic nitrification were observed in SWB-amended soils than in SW-amended soils with a high (4.4 mg N kg−1) amendment level. Conclusions: Our results suggest that SWB is less likely to increase NO3-N accumulation in soil and contributes more to the lower soil autotrophic nitrification rate compared with SW. Although SWB can promote heterotrophic nitrification, it generally inhibits the autotrophic nitrification process and slows the increment pace of the gross nitrification in paddy soils.

17498. 题目: Phosphogypsum as a novel modifier for distillers grains biochar removal of phosphate from water
文章编号: N19090307
期刊: Chemosphere
作者: Bing Wang, Guoqi Lian, Xinqing Lee, Bin Gao, Ling Li, Taoze Liu, Xueyang Zhang, Yulin Zheng
更新时间: 2019-09-03
摘要: A novel biochar composite was fabricated via the pyrolysis of distillers grains treated phosphogypsum for phosphate removal from water. Batch adsorption experiments were performed on the adsorption characteristics of phosphate. Effects of pyrolysis temperature, solution pH, the dosage of adsorbent, ambient temperature on phosphate adsorption were also investigated. The results demonstrated that the optimum initial solution pH for phosphate adsorption was 6.0, and high pyrolysis temperature was favorable for phosphate adsorption. The optimal dosage of biochar was 1.25 g L−1. A pseudo-second-order kinetic model can well explain the adsorption kinetics, indicative of the energetically heterogeneous solid surface of the composite. The maximum phosphate adsorption capacity of the phosphogypsum modified biochar obtained from Langmuir isotherm reached 102.4 mg g1 which was almost five times that of distillers grains biochar alone (21.5 mg g1). The mechanism is mainly attributed to electrostatic adsorption, surface precipitation and ligand exchange. The ideal adsorption performance indicated that biochar supported phosphogypsum can be used as high-quality adsorbent for phosphate removal in wastewater treatment.

17499. 题目: Infiltration behavior of heavy metals in runoff through soil amended with biochar as bulking agent
文章编号: N19090306
期刊: Environmental Pollution
作者: Ling Zhao, Hongyan Nan, Yue Kan, Xiaoyun Xu, Hao Qiu, Xinde Cao
更新时间: 2019-09-03
摘要: Biochar as a porous carbon material could be used for improving soil physical and chemical properties, while insufficient attention has been paid to potential risks induced by infiltration of heavy metals in the runoff water flowing through biochar-amended soil. Four different soil-biochar matrices with same volumes were constructed including soil alone (M1), biochar alone (M2), soil-biochar layering (M3) and soil-biochar mixing (M4). Leaching experiments were conducted with Pb, Cu, and Zn contaminated runoff water. Results showed that biochar amendment greatly improved the water permeation, and the infiltration rates in M2, M3, and M4 were 2.85–23.0 mm min−1, being much higher than those in M1 (1.33–4.05 mm min−1), though the rates decreased as the leaching volumes increased. However, biochar induced more Pb, Cu, and Zn infiltrated through soil-biochar matrix. After 350-L leaching, M1 retained about 95% Pb, 90% Cu, and 36% Zn, while M2 only retained 4.80% Pb, 17.4% Cu, and 4.01% Zn; about 30% Pb, 80% Cu, and 15% Zn were retained in M3 and M4. Notably, Zn was trapped first and then re-leached into the filtrate, which resulted in a much higher effluent Zn than the influent Zn at the later stage. However, the unit weight of biochar showed a higher capacity for retaining heavy metals compared to per unit of soil. Under the dynamic water flow, all benefits and disadvantages induced by biochar were weakened with its physical disintegration. Biochar as soil amendment can enhance plant growth via ameliorating soil structure, while it would pose risks to environment because of large penetration of heavy metals. If biochar was compacted to form a denser physical structure, perhaps more heavy metals could be retained.
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17500. 题目: A comparative study on biochar properties and Cd adsorption behavior under effects of ageing processes of leaching, acidification and oxidation
文章编号: N19090305
期刊: Environmental Pollution
作者: Ruihai Chang, Saran P. Sohi, Fanqi Jing, Yuyan Liu, Jiawei Chen
更新时间: 2019-09-03
摘要: Biochar has potential to control the bioavailability and migration of potentially toxic heavy metals in soil by adsorption. Natural ageing in the environment may change the physicochemical properties and adsorption function of biochar over the long-term. The present study compared the effects of different simulated ageing treatments on Cd adsorption of high and low temperature biochar from straw of corn (Zea mays). Fresh and aged biochars were systematically characterized by elemental analysis, FTIR, XPS, Zeta, SEM-EDS, XRD and the composition of their mineral ash. The adsorption of Cd to fresh and aged biochars was then assessed under the influence of pH. Drawing the results together the effects of ageing on the extent and mode of Cd adsorption could be elucidated. The results showed that the adsorption capacity of fresh biochar produced at 650 °C was higher than of biochar made at 350 °C, and that mineral co-precipitation plays a dominant role in Cd sorption. Leaching removed organic and inorganic ash components from biochars, markedly diminishing the capacity of the high temperature biochar to adsorb Cd. The adsorption performance of the low temperature biochar was dependent on surface complexation. The adsorption capacity of low-temperature biochar was markedly enhanced by oxygen-containing functional groups formed through acidification and oxidation. The long-term benefits of biochar in the management of polluted soil require a rethink, considering the contrasting ageing behavior of different temperature biochar and their response to different ageing environments.
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