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25701. 题目: Dynamics of soil water extractable organic carbon and inorganic nitrogen and their environmental controls in mountain forest and meadow ecosystems in China
文章编号: N19120802
期刊: CATENA
作者: Junjun Zhang, Changhui Peng, Wei Xue, Bin Yang, Zhenan Yang, Shuli Niu, Qiuan Zhu, Meng Wang
更新时间: 2019-12-08
摘要: We investigated the differences among two types of forest (pine and oak forests) and a meadow in soil water extractable organic carbon (WEOC), ammonium (NH₄⁺) and nitrate (NO₃⁻) concentrations in the Qinling Mountains, China. Our results showed that soil WEOC, NH₄⁺ and NO₃⁻ concentrations were higher in the meadow than in the forests, and they were higher in the pine forest than in the oak forest. The soil surface temperature and soil water content were positively correlated with WEOC and inorganic nitrogen concentrations (P < 0.01). In addition, there was a significantly negative correlation between soil WEOC concentration and pH (P < 0.01). Moreover, soil WEOC concentration was positively correlated with the inorganic nitrogen concentration (P < 0.01). Generally, soil WEOC concentration decreased in the forests, and increased in the meadow under warming condition. The effects of warming on soil WEOC and dissolved inorganic nitrogen (DIN) concentrations varied with time. We elucidated that warming had a significant influence on soil WEOC concentration in the pine forest, whereas soil DIN concentration was affected significantly by warming only in the meadow. Our findings indicate that soil WEOC and DIN show different responses to warming in the mountain forest and meadow ecosystems. This study could provide useful insights for the prediction of soil carbon and nitrogen cycling and their responses to climate change in the complex mountain ecosystem.

25702. 题目: Opposite patterns of soil organic and inorganic carbon along a climate gradient in the alpine steppe of northern Tibetan Plateau
文章编号: N19120801
期刊: CATENA
作者: Chenjun Du, Yongheng Gao
更新时间: 2019-12-08
摘要: Both soil organic carbon (SOC) and inorganic carbon (SIC) are important components of soil carbon storage. However, few studies have attempted to estimate the magnitude and patterns of SIC in arid areas. We measured the concentrations of SOC and SIC in alpine steppe grasslands along a climate gradient in the Tibetan Plateau. At all sites, an opposing trend was found in the distribution of SOC compared with SIC. SOC increased with increasing precipitation, while SIC decreased. Within sites, SOC decreased with soil depth, while SIC increased. Among the variables considered, soil total nitrogen (TN) and soil water content explained the most variability in SOC (r² = 0.95 for TN, r² = 0.93 for soil water content), and soil pH had the highest correlation with SIC (r² = 0.90). This finding indicates that SOC is closely related to biological processes, such as biomass input and litter accumulation, while SIC is determined by abiotic factors such as chemical and physical processes of soil formation. SOC and SIC densities showed that the SOC pool comprised 91% of total carbon (TC) storage in these alpine steppe soils. A decrease in SOC density occurred with depth, but this pattern was the opposite for SIC density in all soil profiles. These findings help to characterize the C cycle in the alpine steppe of the Tibetan Plateau.

25703. 题目: Short-term impacts of biochar, tillage practices, and irrigation systems on nitrate and phosphorus concentrations in subsurface drainage water
文章编号: N19120709
期刊: Environmental Science and Pollution Research
作者: Saeid Shahvarooghi Farahani, Mohammad Amin Asoodar, Bijan Khalili Moghadam
更新时间: 2019-12-07
摘要: Leaching of nitrogen (N) and phosphorus (P) from agricultural lands can cause serious environmental problems such as eutrophication. The objective of this study was to investigate the impacts of biochar application, tillage practices, and irrigation systems on nitrate and dissolved phosphorus (DP) concentrations in subsurface drainage water and grain yield of winter wheat using a strip-split plot design with 3 replications. Irrigation at three different levels (flood (I_fl), furrow (I_fu), and sprinkler (I_s) systems) considered as main factor, tillage at two levels (reduced tillage (T_r) and conventional systems (T_c)) as subplot factor, and bagasse biochar at two levels (without biochar (B₀) and 20 ton ha⁻¹ biochar (B₁)) as sub-subplot factor. Polyvinyl chloride (PVC) standpipes were used in each sub-subplot to collect leachate water at 100-cm depth. The results indicated that irrigation had significant effects on yield, collected water volume (CWV), nitrate, and DP concentrations (P < 0.01). Interaction of tillage and irrigation was significant for grain yield (P < 0.05). Biochar application only caused a significant decrease in nitrate concentration under sprinkler irrigation (P < 0.05), while no significant impact was observed under flood and furrow irrigation systems. Under sprinkler irrigation, the total nitrate collected in the PVC standpipes decreased by 37.51 and 34.29% compared with flood and furrow irrigations, respectively. Biochar application reduced the total nitrate collected by 16.84%, while difference among tillage treatments was negligible (4.51%). The total DP collected under sprinkler irrigation was lower in comparison with flood and furrow irrigations by 42.24 and 38.76%, respectively. Biochar application reduced the total DP collected by 10.84%, while reduced tillage increased the total DP collected by 8.90% compared with the conventional tillage.

25704. 题目: 13 C- 14 C relations reveal that soil 13 C-depth gradient is linked to historical changes in vegetation 13 C
文章编号: N19120708
期刊: Plant and Soil
作者: Alexia Paul, Jérôme Balesdent, Christine Hatté
更新时间: 2019-12-07
摘要: Aims: The understanding of the dynamics of subsoil (>30 cm) soil organic matter (SOM) is critical to predict the future evolution of the carbon cycle. Stable carbon isotopes ratios (¹³C/¹²C) are helpful to study the dynamics of SOM, but their variations with depth are still speculative. Methods: Several studies indicated that the ¹³C/¹²C ratio of C₃ vegetation decreased over time more than that of atmospheric CO₂ did. From these studies, we modelled the average variation of δ¹³C values of vegetation from 20,000 years Before Present (BP) to today. Then, we conducted a meta-analysis of the δ¹³C vs ∆¹⁴C values relations in forty-five soil profiles sampled all around the world. Results: We first found evidence of the change in SOM δ¹³C values with the sampling year of the profile. Then, by converting ∆¹⁴C values into mean calendar age of SOM, we showed that 40% of the change in SOM δ¹³C values was explained by the historical change in plant δ¹³C values. Conclusion: We conclude that the average increase of SOM δ¹³C values with depth was mostly linked to the change in vegetation δ¹³C values over the last 20,000 years. The variance around the trend was attributed to the contribution of root derived carbon and to soil processes such as interaction of SOM with minerals or to microbial processes.

25705. 题目: Feasibility of using biochar as buffer and mineral nutrients replacement for acetone-butanol-ethanol production from non-detoxified switchgrass hydrolysate
文章编号: N19120707
期刊: Bioresource Technology
作者: Xiao Sun, Hasan K. Atiyeh, Yinka Adesanya, Christopher Okonkwo, Hailin Zhang, Raymond L. Huhnke, Thaddeus Ezeji
更新时间: 2019-12-07
摘要: Biochar can be an inexpensive pH buffer and source of mineral and trace metal nutrients in acetone-butanol-ethanol (ABE) fermentation. This study evaluated the feasibility of replacing expensive 4-morpholineethanesulfonic acid (MES) P2 buffer and mineral nutrients with biochar made from switchgrass (SGBC), forage sorghum (FSBC), redcedar (RCBC) and poultry litter (PLBC) for ABE fermentation. Fermentations using Clostridium beijerinckii ATCC 51743 in glucose and non-detoxified switchgrass hydrolysate media were performed at 35 °C in 250 mL bottles for 72 h. Medium containing buffer and minerals without biochar was the control. Similar ABE production (about 18.0 g/L) in glucose media with SGBC, FSBC and RCBC and control was measured. However in non-detoxified switchgrass hydrolysate medium, SGBC, RCBC and PLBC produced more ABE (about 18.5 g/L) than the control (10.1 g/L). This demonstrates that biochar is an effective buffer and mineral supplement for ABE production from lignocellulosic biomass without costly detoxification process.
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25706. 题目: Flame retardant property of flax fabrics coated by extracellular polymeric substances recovered from both activated sludge and aerobic granular sludge
文章编号: N19120706
期刊: Water Research
作者: Nam Kyeun Kim, Ningtao Mao, Richard Lin, Debes Bhattacharyya, Mark C.M. van Loosdrecht, Yuemei Lin
更新时间: 2019-12-07
摘要: In this research, extracellular polymeric substances (EPS), such as EPS_flocs and EPS_granules, were successfully extracted from activated and aerobic granular sludge, respectively, and tested as bio-based flame retardant materials. Flax fabric was coated by the biopolymeric substances and its flammability was evaluated based on a vertical burning test defined in US Federal Aviation Regulation. Both EPS_flocs and EPS_granules coated flax fabrics achieved the self-extinguishment due to effective char formation. In particular, the result of the EPS_granules coated sample met the aviation requirements for the aircraft interior. Moreover, the presence of carbonated hydroxyapatite was identified in EPS_granules char residue by using FTIR and XRD analysis. It can contribute to the self-extinguishing property of the fabric by enhancing char formation. Thermogravimetric analysis also demonstrated that EPS_granules coated flax was able to produce greater amount of char residue and its decomposition rate was significantly reduced. This research indicates that there is a great potential to use this biopolymer as a resource for developing high performance bio-inspired flame retardant materials and contribute to a circular economy.
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25707. 题目: Estimation of soil organic carbon losses and counter approaches from organic materials in black soils of northeastern China
文章编号: N19120705
期刊: Journal of Soils and Sediments
作者: Shichao Wang, Yawen Zhao, Jinzhou Wang, Jiajia Gao, Ping Zhu, Xi’an Cui, Minggang Xu, Baoku Zhou, Changai Lu
更新时间: 2019-12-07
摘要: Purpose: The northeast plain of China is one of three extensive regions with black soil rich in organic matter in the northern hemisphere. The replacement of natural grassland with cropland has resulted in massive loss of soil organic carbon (SOC), causing serious degradation in this region. Therefore, long-term field experiments combined with modelling approaches were used to examine and project effects of different soil management practices on SOC sequestration. Materials and methods: The RothC model was used to simulate SOC stocks, and the straw retention factor was adjusted in our study. Strategies for improving carbon sequestration were evaluated over 30 years under four carbon input scenarios: straw return at the current rate (with a straw retention factor of 40%), complete straw retention (with a straw retention factor of 100%), manuring at the current rate (0.43 Mg C ha⁻¹ yr⁻¹), and manuring at double the current rate (0.86 Mg C ha⁻¹ yr⁻¹). Results and discussion: Simulations with the RothC model indicated that the SOC stock in the 0–20-cm soil profile at the experimental sites has decreased by 64.1% since the 1980s. Moreover, SOC levels appear to have declined rapidly during the first 10 years after site reclamation, with losses ranging from 3.51 to 5.89 Mg ha⁻¹ yr⁻¹. Straw return at the current rate was predicted to reduce the SOC sequestration rate by 0.07 Mg ha⁻¹ yr⁻¹ in the northern black soils over the 30-year simulation period but cause SOC levels to slowly increase toward equilibrium in the southern black soil region. In simulations with the higher rate of straw retention, SOC stocks rapidly increased (by 0.36–0.53 Mg ha⁻¹ yr⁻¹) across the black soil region over the 30-year period. SOC stocks also increased under the higher rate of manuring, by 0.01–0.19 Mg ha⁻¹ per year. Conclusions: The results suggest that increasing inputs of carbon sources such as straw and manure, together with appropriate tillage, could substantially improve SOC sequestration in the black soil region of northeastern China.

25708. 题目: Effects of dissolved organic matter derived from freshwater and seawater on photodegradation of three antiviral drugs
文章编号: N19120704
期刊: Environmental Pollution
作者: Chengzhi Zhou, Qing Xie, Jieqiong Wang, Xi Chen, Junfeng Niu, Jingwen Chen
更新时间: 2019-12-07
摘要: Dissolved organic matter (DOM) is the most important light absorber that may induce indirect photolytic transformation of organic pollutants in natural waters. In this study, effects of DOM derived from freshwater and seawater on the photodegradation of three antiviral drugs acyclovir, lamivudine and zidovudine were investigated. Results show that the photodegradation of acyclovir is promoted mainly by excited triplet states DOM (³DOM*), and the photodegradation of lamivudine is accelerated by ³DOM*, •OH and ¹O₂ together; however, the photodegradation of zidovudine is inhibited by DOM mainly via light screening. Compared with DOM from freshwater, promotion effect of DOM extracted from seawater (SDOM) on the photodegradation of acyclovir and lamivudine is weaker, which is attributed to lower productivity of reactive intermediates. On the other hand, inhibitory effect of SDOM on the photodegradation of zidovudine is also weaker, which is due to weaker light screening caused by lower light absorption. Photodegradation half-lives of the three antiviral drugs are predicted to be all more than 20 days in freshwater and seawater bodies of the Yellow River estuarine region. These findings are significant for understanding the phototransformation processes of antiviral drugs and other organic pollutants in estuarine and coastal regions.
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25709. 题目: Bacterial diversity and microbial functional responses to organic matter composition and persistent organic pollutants in deltaic lagoon sediments
文章编号: N19120703
期刊: Estuarine, Coastal and Shelf Science
作者: Annamaria Zoppini, Lucia Bongiorni, Nicoletta Ademollo, Luisa Patrolecco, Tamara Cibic, Annalisa Franzo, Marco Melita, Matteo Bazzaro, Stefano Amalfitano
更新时间: 2019-12-07
摘要: Lagoons in river deltas are highly productive systems that receive high loads of organic matter and nutrients. Among the major environmental stress factors and human health-related issues, the anthropogenic contamination is of particular concern, since coastal lagoons are intensively exploited for aquaculture activities. Although microbial communities constitute the most abundant fraction of the benthic biomass, also providing valuable ecosystem services, the links between sediment quality and microbial processes were largely disregarded. In this study, we aimed to elucidate whether different levels of riverine influence could provide favourable or adverse environmental conditions to sustain microbial diversity and processes. Sediments collected from four lagoons of the Po River delta were analysed to assess biochemical composition (biopolymeric carbon, Bio-PC), target organic pollutants (polycyclic aromatic hydrocarbons, PAHs; nonylphenols; bisphenol A), and microbial community properties (bacterial community composition, prokaryotic biomass, prokaryotic carbon production rate, PCP, community respiration rates, CR, extracellular enzyme activities, EEAs). The major physical and chemical sediment properties allowed identifying two statistically distinct groups of sediments with relatively low (LI) and high (HI) riverine influence. HI sediments were characterised by higher Bio-PC and PAHs concentrations, along with relatively high PAHs potential toxicity estimated by the Toxic Equivalent concentration approach. Contrasting results were obtained by linking the occurrence of dominant bacterial taxa (i.e., Desulfobulbaceae and Desulfobacteraceae) to sediment contamination patterns. Notably, the increasing pollution levels were likely to positively affect the occurrence of the family SVA1033, whereas detrimental effects were found against the family Ectothiorhodospiraceae. In addition, the concurrent increase of PCP/CR ratio along with key EEAs, highlighted that the benthic microbial community could consistently contribute to accelerate the degradation of persistent organic pollutants, with potential implication on the sediment self-purification processes.

25710. 题目: Morphologic and hydrologic distinctions between shallow and deep podzolized carbon in the southeastern United States Coastal Plain
文章编号: N19120702
期刊: Geoderma
作者: Allan R. Bacon, Yaslin N. Gonzalez, Kayci R. Anderson
更新时间: 2019-12-07
摘要: Podzolization imparts soils and landforms of the southeastern United States Coastal Plain with two distinct pools of organic carbon (C), referred to as shallow podzolized C (SPC) and deep podzolized C (DPC). We evaluate podzolization across two catenas, and across the state of Florida, to establish that SPC and DPC are morphologically and hydrologically distinct. We demonstrate that SPC lightens downward (i.e. a Bh horizon with a darker top than bottom) and accumulates below low chroma material, while DPC darkens downward and accumulates below higher chroma material. We interpret these distinct morphologies to be manifestations of separate podzolization processes that are controlled by unique components of soil hydrology. Our analyses support existing notions that SPC is a product of vadose zone hydrology; formed within a pronounced eluvial-illuvial system where C, metals (predominately aluminum), and clay-sized particles are mobilized and immobilized together when near surface saturation thresholds are met. Our work however also identifies DPC to be a product of phreatic zone hydrology; part of an eluvial-illuvial system where C is translocated without metals or clays and immobilized when subsoil saturation thresholds are met. Recognizing the morphologic and hydrologic differences between SPC and DPC not only provides insights into interactions between soil hydrology and terrestrial C cycling in low-relief landforms, but also by incorporating these differences into field-based assessments soil scientists can improve their interpretations and communication of the hydropedology and podzolization.

25711. 题目: Conservation tillage and biochar improve soil water content and moderate soil temperature in a tropical Acrisol
文章编号: N19120701
期刊: Soil and Tillage Research
作者: Alfred Obia, Gerard Cornelissen, Vegard Martinsen, Andreas Botnen Smebye, Jan Mulder
更新时间: 2019-12-07
摘要: Projected climate change in Sub-Saharan Africa involves increased drought and elevated soil temperature. Conservation farming (CF), including minimum tillage, crop rotation and crop residue retention, is proposed as a climate smart soil management option to adapt to climate change through enhanced climate resilience. Here, we determine the effect on soil moisture and temperature of CF planting basins in a Zambian Acrisol. Construction of CF planting basins (40 cm x 15 cm, while 20 cm deep), using hand-hoes, is a commonly used minimum tillage practice among small holders in southern Africa, effectively requiring tillage of only 10 % of a field. The study included basins under regular CF and under CF with 4 t ha⁻¹ pigeon pea biochar (CF + BC). Effects are compared with those in an adjacent soil under conventional tillage, where the entire land surface is ploughed. Soil moisture and temperature sensors were installed in the root zone, 10–12 cm deep, for continuous monitoring during two growing seasons. Soil moisture decreased in the order CF + BC > CF > conventional farming. Due to rainwater harvesting in the basins, maximum soil water retention under CF + BC and CF was greater than under conventional farming (+59 % to +107 % and +15 % to +65 %, respectively). Soil drying after free drainage until permanent wilting point lasted longer under CF + BC (18.4–22.3 days) than under both CF and conventional farming (13.3–18.4 days and 14.9–17.8 days, respectively). In situ soil maximum temperature and diurnal temperature range in the growing season increased in the order CF + BC < CF < conventional farming due to decreases in soil moisture. However, additional laboratory tests, with soil-BC mixtures at field capacity, revealed that BC addition to soil, which caused a decrease in bulk density, also resulted in a significant decline in soil thermal conductivity (p < 0.001). Thus, we hypothesize that BC-enhanced soil moisture in basins helped to reduce soil temperature and its fluctuations, due to both increased heat capacity and decreased thermal conductivity. This study shows that CF in combination with BC in an Acrisol, through enhancing plant-available water and moderating soil temperature, is important for crop productivity and has potential as an element of climate smart agriculture.

25712. 题目: Effects of Sorption on Redox Properties of Natural Organic Matter
文章编号: N19120611
期刊: Environmental Science & Technology
作者: Edisson Subdiaga, Silvia Orsetti, Stefan B. Haderlein
更新时间: 2019-12-06
摘要: Natural organic matter (NOM) is an important redox-active component of natural porous media and predominantly occurs in the sorbed state. Nevertheless, the effects of NOM sorption at minerals on its redox properties are unknown and thus are the major objective of this study. We report how adsorption of three different humic acids (HAs) to redox-inert sorbents (polar Al2O3 and nonpolar DAX-8 resin) affects their electron-exchange capacities (EEC) and redox states. The electron-donating capacity of HAs sorbed at Al2O3 increased by up to 200%, whereas the EEC of the remaining dissolved HA fractions decreased compared with their initial properties. Sorption at DAX-8, however, did not affect significantly the EEC of HAs. We rationalize these results by (i) preferential sorption of NOM components rich in redox-active groups (e.g., quinone, polyphenols) and (ii) surface-catalyzed polymerization of polyphenolic compounds. Our results demonstrate that even in the absence of electron exchange with the sorbent, adsorption to polar mineral surfaces considerably affects the redox properties of NOM. Quantification of the redox state and EEC of adsorbed NOM is thus crucial for assessing electron-transfer processes as well as organic carbon stabilization and sequestration in soils and sediments.

25713. 题目: Molecular Composition of Size-Fractionated Fulvic Acid-Like Substances Extracted from Spent Cooking Liquor and Its Relationship with Biological Activity
文章编号: N19120610
期刊: Environmental Science & Technology
作者: Yuanyuan Yao, Xiaoqi Wang, Yuechao Yang, Tianlin Shen, Chun Wang, Yafu Tang, Zhonghua Wang, Jiazhuo Xie, Lu Liu, Shanmin Hou, Bin Gao, Yuncong C. Li, Yongshan Wan
更新时间: 2019-12-06
摘要: The treatment of spent cooking liquor is critical for clean production of pulp and paper industry. There is a compelling need to develop a cost-effective and green technology for reuse of organic matter in spent cooking liquor to mitigate the negative impacts on the environment. The objective of this study is to examine the chemical structure of fulvic acid-like substances extracted from spent cooking liquor (PFA) and their relationship with bioactivity in plant growth. Compared with the benchmark Pahokee peat fulvic acid (PPFA), PFA has less aromatic structure, but higher content of lignin, carbohydrates, and amino acid. After fractionation, protein/amino proportion decreased with increasing molecular weight, but the aromaticity increased. Under salt stress, rice seedling growth was promoted by PFA with low molecular weight (<5 kDa), but inhibited by fraction with high molecular weight (>10 kDa). Principal component analysis suggested that promoted growth was more related with chemical structure (O- and N-alkyl moieties) than with molecular weight. This study provided the theoretical basis for development of an innovative green technology of sustainable reuse of spent cooking liquor in agriculture.

25714. 题目: Depth‐dependent detritus production in the sponge, Halisarca caerulea
文章编号: N19120609
期刊: Limnology and Oceanography
作者: Michael P. Lesser, Benjamin Mueller, M. Sabrina Pankey, Keir J. Macartney, Marc Slattery, Jasper M. de Goeij
更新时间: 2019-12-06
摘要: Sponges are important ecological and functional components of coral reefs. Recently, a new hypothesis about the functional ecology of sponges in organic matter recycling pathways, the sponge‐loop hypothesis, in which dissolved and particulate organic matter is taken up by sponges and shunted to higher trophic levels as detritus, has been proposed and demonstrated for shallow (< 30 m) cryptic species. However, support for this hypothesis at mesophotic depths (∼ 30–150 m) is lacking. Here, we examined detritus production, a prerequisite of the sponge loop pathway, in a reciprocal transplant experiment, using Halisarca caerulea from water depths of 10 and 50 m. Detritus production was significantly lower in mesophotic sponges compared to shallow samples of H. caerulea. Additionally, detritus production rates in transplanted sponges moved in the direction of rates observed for resident conspecifics. The microbiome of these sponge populations was also significantly different between shallow and mesophotic depths, and the microbial communities of the transplanted sponges also shifted in the direction of their new depth in 10 d largely driven by changes in Oxyphotobacteria, Acidimicrobiia, Nitrososphaeria, Nitrospira, Deltaproteobacteria, and Dadabacteriia. This occurred in an environment where the availability of both dissolved and particulate trophic resources changed significantly across the shallow to mesophotic depth gradient where these sponge populations were found. These results suggest that changes in sponge detritus production are primarily driven by differential quality and quantity of trophic resources, as well as their utilization by the sponge host, and its microbiome, along the shallow to mesophotic depth gradient.

25715. 题目: Effect of water leaching on biochar properties and its impact on organic contaminant sorption
文章编号: N19120608
期刊: Environmental Science and Pollution Research
作者: Inga J. Schreiter, Wolfgang Schmidt, Abhay Kumar, Ellen R. Graber, Christoph Schüth
更新时间: 2019-12-06
摘要: When biochar (BC) is applied to soil, one process that can alter its properties and contaminant sorption is the leaching of minerals and dissolved organic carbon (DOC). This study investigated changes in properties of three BCs (cattle manure, grain husk, and wood chips), due to leaching, and the subsequent impact on sorption of trichloroethylene (TCE) and tetrachloroethylene (PCE). The manure-derived BC released 27.4 mg g⁻¹ DOC, which is over ten times more than that measured for the two plant-based BCs (2.5 and 1.5 mg g⁻¹ DOC for grain husk and wood chips, respectively). In all leachates, potassium is the dominant cation, whereas chloride, sulfate, and phosphate are the main anions. In total, the manure-derived biochar released the highest sum of total ions (73.1 mg g⁻¹), followed by BC produced from grain husk (15.5 mg g⁻¹) and wood chips (1.2 mg g⁻¹). Leaching increased external surface area, mesopore volume, and hydrophobicity of the manure-derived BC and decreased its polarity. This enhanced sorption via partitioning. In plant-based BCs, micropore volume and size distribution were altered, most likely through the un-blocking of pores, causing increased sorption via pore-filling for both TCE and PCE. The results indicate that, depending on feedstock material, BC leaching can alter the environmental fate of organic compounds.

25716. 题目: Spatial and temporal variations of CO₂ emissions from the active fault zones in the capital area of China
文章编号: N19120607
期刊: Applied Geochemistry
作者: Zhi Chen, Ying Li, Giovanni Martinelli, Zhaofei Liu, Chang Lu, Yuanxin Zhao
更新时间: 2019-12-06
摘要: The chemical and isotopic composition of 26 soil gas wells and 11 springs along the active fault zones in the capital area of China was determined to investigate the origin of CO₂, the spatial and temporal variations of CO₂ emission, and their mechanisms. The chemical and isotopic data indicated that biogenic CO₂ was the primary source for CO₂ from the soil gas wells in both the basin and orogen regions, the crust-derived and mantle-derived CO₂ could have ascended through the deep-cut faults and got into the springs, with a few diffusing into the soil gas wells. Minor air could have intruded into the soil gas wells in the orogen region through the faults cutting the surface, owing to the barometric pressure fluctuation. Relatively high He concentration, CO₂ concentration, and flux of soil gas from wells were observed in the basin region than those in the orogen region. A significant amount of CO₂ is produced during the process of oxidation of organic matter in the basin, where the organic matter accumulates in thick clayey strata. Further amounts of CO₂ are produced by interactions between groundwaters and carbonates, which are widely represented in the basin region and by intruded air into the soil gas wells in the orogen region due to barometric pressure fluctuations. Temporal variations of CO₂ concentration and CO₂ flux were observed in soil gas wells in the basin region, where seismic activity is more frequent compared to those in the orogen, indicating that seismic activity could be responsible for the jumpily temporal variations of CO₂ concentration and flux in wells. Monitoring activities of soil gas CO₂ concentrations and CO₂ fluxes in active fault zones should be carried out.

25717. 题目: Redox-active biochar facilitates potential electron tranfer between syntrophic partners to enhance anaerobic digestion under high organic loading rate
文章编号: N19120606
期刊: Bioresource Technology
作者: Gaojun Wang, Qian Li, Yu Li, Yao Xing, Gaofei Yao, Yanzheng Liu, Rong Chen, Xiaochang C. Wang
更新时间: 2019-12-06
摘要: Sawdust-based biochar prepared (SDBC) at three pyrolytic temperatures were compared as additives to mesophilic anaerobic digestion (AD). SDBC prepared at 500°C performed better in enhancing CH₄ production than other SDBCs. Analyzing the crucial electro-chemical characteristics of the SDBCs revealed that the excellent electron transfer capacity of SDBC was significant to stimulate methanogenesis promotion. A long-term semi-continuous operation further confirmed that adding SDBC to AD system increased the maximum organic loading rate (OLR) from 6.8gVS/L/d to 16.2gVS/L/d, which attributed to the extremely low volatile fatty acids (VFA) accumulation. Microbial community succession analysis found that SDBC addition altered both bacterial and archaea structure greatly. More importantly, the syntrophic and electro-active partners of Petrimonas and Methanosarcina synergistically enriched under high OLR condition were responsible for the high-efficient VFA degradation, which suggested that SDBC likely acted as redox-active mediator to facilitate direct interspecies electron transfer between the syntrophic partners for high-efficient syntrophic methanogenesis process.
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25718. 题目: Rice straw, biochar and calcite incorporation enhance nickel (Ni) immobilization in contaminated soil and Ni removal capacity
文章编号: N19120605
期刊: Chemosphere
作者: Umeed Ali, Muhammad Shaaban, Saqib Bashir, Ruili Gao, Qingling Fu, Jun Zhu, Hongqing Hu
更新时间: 2019-12-06
摘要: Although rice straw (RS), biochar (BI) and calcite (CC) have proved to be effective immobilizing agents in acidic contaminated soil, we lack up-to-date scientific data regarding nickel (Ni) fractionation in soil and removal capacity in water. Therefore, an incubation study was undertaken to investigate the efficacy of RS, BI and CC with three application rates (0, 1 and 2%) of RS, BI and CC on the immobilization of Ni in polluted soil. Various extraction techniques were carried out: sequential extraction procedure, the European Community Bureau of Reference (BCR), extraction with CaCl_2, and the toxicity characteristics leaching procedure (TCLP) techniques. Additionally, Ni sorption behavior was determined using the Langmuir and Freundlich isotherms. Results showed that adding all amendments into Ni contaminated acidic soil, enhanced soil pH, reduced the exchangeable fraction of Ni by 48%–55%, 59%–71% and 58%–66.3%, when RS, BI and CC were applied at 1% and 2% rates, respectively. According to the Langmuir adsorption isotherm results, the maximum sorption capacity was recorded using 2747 mg kg⁻¹ in 2% CC amended soil. However, biochar exhibited the maximum Ni sorption capacity (13348 mg kg⁻¹), due to its porous structure, larger surface area, and having more functional groups. Furthermore, the results of FTIR, SEM and zeta potential techniques confirmed that the immobilization and biochar’s capacity to remove Ni were more effective when compared to other immobilizing agents.

25719. 题目: Amending an As/Pb contaminated soil with biochar, compost and iron grit: effect on Salix viminalis growth, root proteome profiles and metal(loid) accumulation indexes
文章编号: N19120604
期刊: Chemosphere
作者: Manhattan Lebrun, Elena De Zio, Florie Miard, Gabriella S. Scippa, Giovanni Renzone, Andrea Scaloni, Sylvain Bourgerie, Domenico Morabito, Dalila Trupiano
更新时间: 2019-12-06
摘要: There is currently a large amount of research being done into the phytoremediation of polluted soils. Plant installation in contaminated soils may require the application of soil amendments, such as biochar, compost and/or iron grit, which can improve the soil conditions and reduce the metal (loid) phytoavailability and mobility. The beneficial effects of these amendments on soil properties, plant growth and metal (loid) accumulation ability have already been described, although their effect on the plants response machinery has been poorly studied. This study aimed to assess the effect of these amendments on Salix viminalis growth and metal (loid) accumulation, as well as elucidating associated molecular mechanisms. The results showed that the amendment applications improved plant growth by three fold, except for the biochar plus iron combination. It also revealed that metal (loid)s were not effectively translocated from the roots to the shoots (translocation factors <1), their bioaccumulation peaked in the roots, and increased in the presence of iron-based amendments. Corresponding proteomic profiles revealed 34 protein spots differentially represented and suggested that plants counteracted metal (loid)-induced oxidative stress after the addition of biochar and/or compost by eliciting proper defense and signaling pathways, and by redirecting the metabolic fluxes towards primary and secondary metabolism. However, they did highlight the occurrence of oxidative stress markers when the biochar plus iron amendment was applied, which could be both the cause and result of protein degradation impairment.

25720. 题目: Progress, challenges, and opportunities in enhancing NOM flocculation using chemically modified chitosan: a review towards future development
文章编号: N19120603
期刊: Environmental Science: Water Research & Technology
作者: Paripurnanda Loganathan, Michael Gradzielski, Heriberto Bustamante, Saravanamuthu Vigneswaran
更新时间: 2019-12-06
摘要: Natural organic matter (NOM) occurs ubiquitously in water bodies and this can greatly affect feed or raw water quality (taste, colour, odour, bacterial growth). Furthermore, it reduces the performance of the coagulation-based water treatment process. Because the NOM content and its chemical complexity are increasing throughout the world, the removal of NOM from water has become a major challenge in supplying the required amounts of good quality water. The coagulation–flocculation process is widely used for purifying urban water supplies. However, it is not always sufficiently successful in removing the augmented NOM in the feed water, mostly because the polyelectrolytes currently used as coagulants/flocculants cannot effectively interact with all the NOM components consisting of different functional groups, molecular weights, charges, and hydrophobicity. Within the class of polyelectrolytes, chitosan (Cs), which is produced by the deacetylation of abundantly available chitin, has been tested in removing NOM. The effectiveness of Cs can be further improved by chemically modifying the abundant free amino and hydroxyl groups along the Cs chain backbone. This will provide new functional groups that can increase the positive charges, molecular weight, and allow for solubility over a wider pH range, as well as introduce tailored groups which interact in an optimised way with NOM, thereby reducing the solubility of the formed complexes. This paper critically reviews the chemistry of the formed polyelectrolyte/NOM complexes and provides information on how this can be taken advantage of, to identify modified chemical structures of Cs to improve NOM removal in water treatment strategies.
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