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所有论文

101. 题目: Evaluating the performance of inorganic draw solution concentrations in an anaerobic forward osmosis membrane bioreactor for real municipal sewage treatment
文章编号: N20040108
期刊: Bioresource Technology
作者: Yue Gao, Zhou Fang, Cheng Chen, Xianzheng Zhu, Peng Liang, Yong Qiu, Xiaoyuan Zhang, Xia Huang
更新时间: 2020-04-01
摘要: Sewage can become a valuable source if its treatment is re-oriented for recovery. An anaerobic forward osmosis membrane bioreactor (AnOMBR) was developed for real municipal sewage treatment to investigate performance, biogas production, flux change and mixed liquor characteristics. The AnOMBR had a good treatment capacity with removal ratio of chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorus more than 96%, 88%, 89% and almost 100%. Although high DS concentration increased the initial flux, it caused rapid decline and poor recoverability of FO membrane flux. Low DS concentration led to too long hydraulic retention time, thus resulting in a low reactor efficiency. Additionally, it was observed that salt, protein, polysaccharide and humic acid were all accumulated in the reactor, which was not conducive to stable long-term operation. Based on the characteristics of membrane fouling, salt accumulation and AnOMBR performance, the optimal DS of 1 M NaCl solution was selected.

102. 题目: Nanoscale Pisum sativum pods biochar encapsulated starch hydrogel: A novel nanosorbent for efficient chromium (VI) ions and naproxen drug removal
文章编号: N20040107
期刊: Bioresource Technology
作者: Asmaa K. Mohamed, Mohamed E. Mahmoud
更新时间: 2020-04-01
摘要: Assembly of novel ecofriendly and sustainable (N-PSPB/SHGL) nanosorbent was fabricated based on encapsulation of derived nanoscale spherical biochar from Pisum sativum pods (N-PSPB) with starch hydrogel (SHGL). The mass ratio between starch and N-PSPB was examined and 2% (w/w) was selected as the optimum percentage for fabrication of the assembled hydrogel. High swelling capacity was characterized by N-PSPB/SHGL nanosorbent (500.0%) at room temperature (25°C), excellent stability for ten cycles with respect to regeneration by 0.1 mol L-1 HCl. Additionally, characterizations of N-PSPB/Starch nanosorbent were established by SEM and BET measurement to characterize surface area (226.94 m2/g) and pore volume (9.88 cm3/g). The N-PSPB/SHGL nanosorbent was subjected to extensive investigations to evaluate its efficiency for removal of naproxen drug (NAP) and chromium (VI). The Cr(VI) and NAP drug adsorptions were fitted to pseudo-second kinetic and correlated with Langmuir isotherm. The adsorption processes were spontaneous and endothermic based on thermodynamic study.

103. 题目: Phosphorus Speciation in Atmospherically Deposited Particulate Matter and Implications for Terrestrial Ecosystem Productivity
文章编号: N20040106
期刊: Environmental Science & Technology
作者: Peggy A. O’Day, Ugwumsinachi G Nwosu, Morgan E. Barnes, Stephen C. Hart, Asmeret Asefaw Berhe, John N. Christensen, Kenneth H. Williams
更新时间: 2020-04-01
摘要: Chemical forms of phosphorus (P) in airborne particulate matter (PM) are poorly known and do not correlate with solubility or extraction measurements commonly used to infer speciation. We used P X-ray absorption near-edge structure (XANES) and 31P nuclear magnetic resonance (NMR) spectroscopies to determine P species in PM collected at four mountain sites (Colorado and California). Organic P species dominated samples from high elevations, with organic P estimated at 65–100% of total P in bulk samples by XANES and 79–88% in extracted fractions (62–84% of total P) by NMR regardless of particle size (≥10 or 1–10 μm). Phosphorus monoester and diester organic species were dominant and present in about equal proportions, with low fractions of inorganic P species. By comparison, PM from low elevation contained mixtures of organic and inorganic P, with organic P estimated at 30–60% of total P. Intercontinental PM transport determined from radiogenic lead (Pb) isotopes varied from 0 to 59% (mean 37%) Asian-sourced Pb at high elevation, whereas stronger regional PM inputs were found at low elevation. Airborne flux of bioavailable P to high-elevation ecosystems may be twice as high as estimated by global models, which will disproportionately affect net primary productivity.

104. 题目: Heterogeneous Diffusion of Polystyrene Nanoparticles through an Alginate Matrix: The Role of Cross-linking and Particle Size
文章编号: N20040105
期刊: Environmental Science & Technology
作者: Joann M. Rodríguez-Suárez, Caitlyn S. Butler, Anne Gershenson, Boris L. T. Lau
更新时间: 2020-04-01
摘要: Most bacteria in natural and engineered environments grow and exist in biofilms. Recent investigations have shown that nanoparticles (NPs) interact with environmental biofilms, but these interactions are still not well characterized. Extracellular polymeric substances (EPS) are polymers secreted by bacteria to establish the functional and structural integrity of biofilms, and EPS porosity is a major contributor to NP access to and diffusion in biofilms. We used a synergistic combination of total internal reflection fluorescence microscopy and image correlation spectroscopy to monitor and map diffusion of fluorescent NPs in alginate yielding a detailed picture of the heterogeneous structure and connectivity of pores within a model EPS polymer. Using different sizes (20, 100, and 200 nm) of carboxylated polystyrene NPs, we examined how NP diffusive behaviors change as a result of calcium-induced cross-linking of the alginate matrix. This study reveals that cross-linking decreases NP diffusion coefficients and pore accessibility in an NP size-dependent manner and that NP movement through alginate matrices is anisotropic and heterogeneous. These results on heterogeneous and size-dependent movement within biofilms have important implications for future studies and simulations of NP-biofilm interactions.

105. 题目: Changes in soil organic carbon fractions and residence time five years after implementing conventional and conservation tillage practices
文章编号: N20040104
期刊: Soil and Tillage Research
作者: Mehdi Rahmati, Iraj Eskandari, Mehdi Kouselou, Vali Feiziasl, Gholam Reza Mahdavinia, Nasser Aliasgharzad, Blair M. McKenzie
更新时间: 2020-04-01
摘要: Tillage not only affects the quantity of soil organic carbon, SOC, but also its quality. Therefore, an investigation was conducted to see how a five-year (2011–2016) implementation of conventional tillage, CT, and conservation tillage practices, CTP's, under dryland vetch – wheat farming system can affect the total organic carbon, TOC, of soil and its fractions as well as its biological indicators including the half-life of organic materials, HL, and the mean residence time, MRT. The applied tillage practices included three CTP's of reduced tillage, RT, with chisel plow, minimum tillage, MT, with stubble cultivator, and no-tillage, NT, with direct seeding as well as one conventional tillage, CT, with moldboard plow. The results revealed that all applied CTP's (RT, MT, and NT) significantly increased the TOC of examined surface soils (0−25 cm) compared to CT. The labile fraction of SOC (dissolve organic carbon, DOC) under CTP's, excluding NT, showed a significant decrease compared to CT. While MT significantly increased the fraction of organic carbon stabilized by clay and silt particles, OC{c + s} compared to CT, NT and RT made no considerable change in OC{c + s} compared to CT. There was also a considerable (but insignificant) increase in the amount of organic carbon stabilized by sand and aggregates plus particulate organic matter, OC{S + A+POM}, under CTP's compared to CT. We recorded the greatest (228 ± 21 μg N g−1 2 h−1) and least (98 ± 27 μg N g−1 2 h−1) activity of urease under RT and CT systems, respectively, and the differences were significant. Based on the incubation data, the NT and RT systems significantly resulted in highest HL, (170 ± 9 days) for soil organic materials while CT had the lowest HL, (127 ± 5 days). While RT showed significantly the highest aggregate stability (55 ± 7 %), the CT and MT had the lowest aggregate stability (29 ± 4 %). In general, our results demonstrated the benefits of CTP's, and more specifically the benefits of RT and NT systems, in improving SOC, as primary indicator of soil quality, in surface soils under dryland agriculture in terms of quantity and quality of organic carbon.

106. 题目: Biochar enhanced the nitrifying and denitrifying bacterial communities during the composting of poultry manure and rice straw
文章编号: N20040103
期刊: Waste Management
作者: Mohd Huzairi Zainudin, Nurul Asyifah Mustapha, Toshinari Maeda, Norhayati Ramli, Kenji Sakai, Mohd Hassan
更新时间: 2020-04-01
摘要: Biochar has proven to be a feasible additive for mitigating nitrogen loss during the composting process. This study aims to evaluate the influence of biochar addition on bacterial community and physicochemical properties changes, including ammonium (NH4+), nitrite (NO2−) and nitrate (NO3−) contents during the composting of poultry manure. The composting was carried out by adding 20% (w/w) of biochar into the mixture of poultry manure and rice straw with a ratio of 2:1, and the same treatment without biochar was prepared as a control. The finished product of control compost recorded the high contents of NO2− and NO3− (366 mg/kg and 600 mg/kg) with reduced the total NH4+ content to 10 mg/kg. Meanwhile, biochar compost recorded a higher amount of total NH4+ content (110 mg/kg) with low NO2− and NO3− (161 mg/kg and 137 mg/kg) content in the final composting material. The principal component analysis showed that the dynamics of dominant genera related to Halomonas, Pusillimonas, and Pseudofulvimonas, all of which were known as nitrifying and denitrifying bacteria, was significantly correlated with the dynamic of NO2− and NO3− content throughout the composting process. The genera related to Pusillimonas, and Pseudofulvimonas appeared as the dominant communities as the NO2− and NO3− increased. In contrast, as the NO2− and NO3− concentration decreased, the Halomonas genus were notably enriched in biochar compost. This study revealed the bacterial community shifts corresponded with the change of physicochemical properties, which provides essential information for a better understanding of monitoring and improving the composting process.

107. 题目: Variations in CH4 and CO2 productions and emissions driven by pollution sources in municipal sewers: An assessment of the role of dissolved organic matter components and microbiota
文章编号: N20040102
期刊: Environmental Pollution
作者: Hao Chen, Jianfeng Ye, Yafei Zhou, Zhongning Wang, Qilong Jia, Yunhan Nie, Lei Li, Hui Liu, Gaboury Benoit
更新时间: 2020-04-01
摘要: Variations in methane (CH4) and carbon dioxide (CO2) emissions in municipal sewer driven by pollution sources are complex and multifaceted. It is important to investigate the role of dissolved organic matter (DOM) components and microbiota to better understand what and how those variations occurred. For this purpose, this study provides a systematic assessment based on short-term in-sewer conditioned cultivations, in conjunction with a field survey in four typical sewers in Shanghai Megacity. The results are as follows: (1) Sediment plays a main role in driving the sewer carbon emission behavior owing to its strong associations with the utilized substrates and predominant microbes that significantly promoted the gas fluxes (genera Bacteroidete_vadinHA17, Candidatus_competibacter, and Methanospirillum). (2) Aquatic DOM in overlying water is an indispensable factor in promoting total carbon emissions, yet the dominant microbes present there inversely correlated with gas fluxes (genera Methanothermobacter and Bacteroides). (3) The total fluxes of both CH4 and CO2 enhanced by pavement runoff were limited. Its high COD-CH4/CO2 conversion efficiencies can be ascribed to its dominant anthropogenic humic-like components and the emerged aquatic tyrosine-like components. (4) Domestic sewage can significantly enhance the total fluxes because of its high concentration of bioavailable DOM. However, these substrates, which were more suitable for supporting microbial growth, as well as the substrate competition caused by sulfate reduction and the nitrogen cycle (revealed by the dominant functional microbes genera Acinetobacter, Pseudomonas, Dechloromona, and Candidatus_competibacter and their correlations with indicators), seemed to be responsible for the low COD-CH4/CO2 conversion efficiencies of domestic sewage. (5) A field survey indicated the distinct features of carbon emissions of sewer sewage discharged from different catchments. An extreme hydraulic condition in a sewer in the absence of influent showed unexpectedly high levels of CO2, while a small amount of CH4 emissions.

108. 题目: Sulfide reduction can significantly enhance transport of biochar fine particles in saturated porous medium
文章编号: N20040101
期刊: Environmental Pollution
作者: Pengkun Ma, Wei Chen
更新时间: 2020-04-01
摘要: The release of fine particles from biochar materials applied in the environment may have important environmental implications, such as mobilization of environmental contaminants. In natural environments biochar fine particles can undergo various transformation processes, which may change their surface chemistry and consequently, the mobility of the particles. Here, we show that sulfide reduction can significantly alter the transport of wheat-straw- and pine-wood-derived biochar fine particles in saturated porous media. Counterintuitively, the sulfide-reduced biochar particles exhibited greater mobility in artificial groundwater than their non-reduced counterparts, even though reduction led to decrease of surface charge negativity and increase of hydrophobicity (from the removal of surface O-functional groups), both should favor particle deposition, as predicted based on extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. Using transport experiments conducted in single-cation background solutions containing K+, Mg2+ or Ca2+ under different pH conditions, we show that the surprisingly greater mobility of sulfide-reduced biochar particles was attributable to the removal of surface carboxyl groups during reduction, as this markedly alleviated particle deposition through cation bridging, wherein Ca2+ acted as the bridging agent in linking the surface O-functional groups of biochar particles and quartz sand. These findings show the critical roles of surface properties in dictating the mobility of biochar fine particles and call for further understanding of their transport properties, which apparently cannot be simply extrapolated based on the findings of other (engineered) carbonaceous nanomaterials.

109. 题目: Contribution of electroactive humic substances to the iron‐binding ligands released during microbial remineralisation of sinking particles
文章编号: N20033104
期刊: Geophysical Research Letters
作者: Hannah Whitby, Matthieu Bressac, Géraldine Sarthou, Michael J. Ellwood, Cécile Guieu, Philip W. Boyd
更新时间: 2020-03-31
摘要: Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing the ligand pool composition are poorly constrained, limiting our understanding of the controls on dissolved iron distributions. To address this, the release of iron and iron‐binding ligands during the microbial remineralisation of sinking particles was investigated by deploying in situ particle interceptor/incubator devices at subsurface sites in the Mediterranean Sea and Subantarctic. Analyses revealed the pool of released ligands was largely dominated by electroactive humic substances (74 ± 28%). The release of ligands during remineralisation ensured that concurrently released iron remained in solution, which is crucial for iron regeneration. This study presents compelling evidence of the key role of humic ligands in the subsurface replenishment of dissolved iron and thus on the wider oceanic dissolved iron inventory, which ultimately controls the magnitude of iron resupplied to the euphotic zone.

110. 题目: Coupling characteristics and environmental significance of nitrogen, phosphorus and organic carbon in the sediments of Erhai Lake
文章编号: N20033103
期刊: Environmental Science and Pollution Research
作者: Haixiang Zhao
更新时间: 2020-03-31
摘要: The contents and forms of nitrogen (N), phosphorus (P), and organic carbon (C) were determined with 40 cm (approximately 1600 s) core sediments from Erhai Lake on the Yungui Plateau of China as the sample. The vertical distribution characteristics, coupling relationships and ecological indicator significance of C–N–P were studied and identified. The results showed that the total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) contents were in the ranges of 1436–8255 mg·kg−1, 1287–5462 mg·kg−1, and 870.26–1507.74 mg·kg−1, respectively. In the Erhai Lake sediments, the main forms of TOC, organic nitrogen (ON) and organic phosphorus (OP) were humus, TN, and TP, respectively. The deposition of C, N, and P in the Erhai Lake sediments was divided into four periods. In the initial development period (from 40 to 23 cm), C, N and P were deposited and released synchronously; the main form of N was nontransferable total nitrogen (NTN), and that of P was inorganic phosphorus (IP). In the ecological recovery period (from 22 to 14 cm), C and N were deposited synchronously, and their deposition amounts were more than that of P. C, N and P were released synchronously. The main form of N was transferable total nitrogen (TTN), and that of P was IP. In the rapid economic growth period (from 13 to 0 cm), C, N, and P were deposited and released synchronously; the main form of N was NTN, and that of P was OP. In comparison to the other periods, this period was a period of higher active soil organic carbon (ASOC). In the integrated management period (surface sediment), C and N were deposited and released synchronously, and their deposition amounts were greater than that of P. The main form of N was NTN, that of P was OP, and the ASOC content was high. When exogenous inputs were the main sources of C, N, and P, the deposition forms of P and N were mainly OP and NTN, respectively, and those of IP and TTN were calcium-bound P (Ca–P) and ion-exchange form N (IEF–N), respectively. When endogenous inputs were the main sources of C, N and P, the deposition forms of P and N were mainly IP and TTN, respectively, and those of IP and TTN were Fe/Al–P and weak acid extractable form (WAEF–N), respectively. The content ratio of Ca–P and Fe/Al–P, as well as that of IEF–N and WAEF–N, could reflect the changes in the contribution of endogenous and exogenous sources to the Erhai Lake sediments.

111. 题目: Iron Speciation in Organic Matter Fractions Isolated from Soils Amended with Biochar and Organic Fertilizers
文章编号: N20033102
期刊: Environmental Science & Technology
作者: Beatrice Giannetta, César Plaza, Matthew G. Siebecker, Giuliana Aquilanti, Costantino Vischetti, Jasper Rikkert Plaisier, Miguel Juanco, Donald L. Sparks, Claudio Zaccone
更新时间: 2020-03-31
摘要: The role and distribution of iron (Fe) species in physical soil fractions have received remarkably little attention in field-scale systems. Here, we identify and quantify the Fe phases into two fractions (fine sand, FSa, and fine silt and clay, FSi + Cl), isolated from an agricultural soil unamended and amended with different organic materials, by Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. The linear combination fitting and wavelet transform of EXAFS data revealed noticeable differences between unamended FSa and FSi + Cl fractions. Specifically, the FSi + Cl fraction was mainly characterized by ferrihydrite (48%) and Fe(III)–soil organic matter (SOM) complexes (37%), whereas in the FSa fraction, ferrihydrite still represented a major phase (44%), with a lower contribution from Fe(III)–SOM (18%). In the FSa fraction, the addition of the organic amendments resulted in an increase of Fe–SOM complexes (31–35%) and a decrease of ferrihydrite (28–29%). By contrast, in the amended FSi + Cl fractions, the added organic matter led to negligible changes in percent ferrihydrite. Therefore, regardless of the amendment type, the addition of organic matter to soil increased the capability of the coarse fraction (FSa) to stabilize organic carbon, thus pointing out that the role of FSa in carbon sequestration in agricultural soils at a global scale may be overlooked.

112. 题目: Reduced net methane emissions due to microbial methane oxidation in a warmer Arctic
文章编号: N20033101
期刊: Nature Climate Change
作者: Youmi Oh, Qianlai Zhuang, Licheng Liu, Lisa R. Welp, Maggie C. Y. Lau, Tullis C. Onstott, David Medvigy, Lori Bruhwiler, Edward J. Dlugokencky, Gustaf Hugelius, Ludovica D’Imperio, Bo Elberling
更新时间: 2020-03-31
摘要: Methane emissions from organic-rich soils in the Arctic have been extensively studied due to their potential to increase the atmospheric methane burden as permafrost thaws. However, this methane source might have been overestimated without considering high-affinity methanotrophs (HAMs; methane-oxidizing bacteria) recently identified in Arctic mineral soils. Herein we find that integrating the dynamics of HAMs and methanogens into a biogeochemistry model8,9,10 that includes permafrost soil organic carbon dynamics3 leads to the upland methane sink doubling (~5.5 Tg CH4 yr−1) north of 50 °N in simulations from 2000–2016. The increase is equivalent to at least half of the difference in net methane emissions estimated between process-based models and observation-based inversions, and the revised estimates better match site-level and regional observations. The new model projects doubled wetland methane emissions between 2017–2100 due to more accessible permafrost carbon. However, most of the increase in wetland emissions is offset by a concordant increase in the upland sink, leading to only an 18% increase in net methane emission (from 29 to 35 Tg CH4 yr−1). The projected net methane emissions may decrease further due to different physiological responses between HAMs and methanogens in response to increasing temperature.

113. 题目: Response of soil fertility characteristics in water-stable aggregates to tea cultivation age in hilly region of southern Guangxi, China
文章编号: N20033003
期刊: CATENA
作者: Shengqiang Wang, Zhe Zhang, Shaoming Ye
更新时间: 2020-03-30
摘要: Research on the changes of soil aggregate-relevant organic C (Corg) and nutrients in different aged tea plantations is essential for improving our understanding of soil Corg mitigation and nutrient restitution during tea cultivation. In this study, soil Corg, total nitrogen (Ntot), available phosphorus (Pava), and the exchangeable cations (that is, potassium (K+), sodium (Na+), calcium (Ca2+), and magnesium (Mg2+)) were measured in soil aggregates (0–20 cm depth) from different aged (8-, 17-, 25-, and 43-yr.) tea plantations in the hilly region of southern Guangxi, China. Soil aggregates were divided into large macro-aggregates (>2 mm), medium macro-aggregates (2–1 mm), small macro-aggregates (1–0.25 mm), and micro-aggregates (<0.25 mm) according to a wet-sieving procedure. The tea plantations of 17-yr. were related to the highest stability of soil aggregates; meanwhile, both large macro-aggregates and micro-aggregates were the major fractions carrying soil Corg and nutrients. Long-term tea cultivation was beneficial to soil Corg, Ntot, and Pava accumulating processes; nevertheless, the increase rates of their storages were declined in the bulk soil as the tea cultivation age increased. Differently, soil exchangeable cation storages decreased with time, and the decreasing rates at the middle phase (from 17- to 25-yr.) of tea cultivation were higher than those at other phases. Hence, developing and implementing a sustainable management scheme is critical to keeping the stability of soil aggregates and maximally reducing the losses of soil exchangeable cations in the process of tea cultivation, particularly after 17-yr., in the hilly region of southern Guangxi, China.

114. 题目: Characteristics of organic material inputs affect soil microbial NO 3 − immobilization rates calculated using different methods
文章编号: N20033002
期刊: European Journal of Soil Science
作者: Zhao-Xiong Chen, Hui-Min Zhang, Xiao-Shun Tu, Xin Sun, Jing Wang, Yi Cheng, Jin-Bo Zhang, Zu-Cong Cai, Scott X. Chang
更新时间: 2020-03-30
摘要: Microbial immobilization of nitrate (NO3−) is considered as an important process in reducing NO3 − accumulation and regulating nitrogen (N) retention capacity in soils. Accurately quantifying the rate of microbial NO3− immobilization is therefore necessary to predict its role in lowering NO3− accumulation in soils. We compared microbial NO3− immobilization rates using a 15NO3− labelling technique in three different ways: (i) 15N pool dilution, (ii) organic 15N recovery and (iii) microbial biomass 15N recovery in a nitrate‐rich upland soil with and without amendment with organic materials with differing C/N ratios. The three methods generated similar NO3− immobilization rates, except when the soil was amended with easily decomposable organic materials (glucose and sucrose). We also developed a microbial NO3− immobilization‐specific quality index that incorporates C/N ratio, contents of lignin, cellulose and hemicellulose contents, and pH for slowly decomposing organic materials (plant residues). This study provides a direct empirical evidence that the results of different methods for calculating soil microbial NO3− immobilization rates are affected by the characteristics of organic materials amended to the soil.

115. 题目: Recycling of powder coke to cost effective adsorbent material and its application for tertiary treatment of coking wastewater
文章编号: N20033001
期刊: Journal of Cleaner Production
作者: Chen Zhang, Jianfeng Li, Fangqin Cheng
更新时间: 2020-03-30
摘要: Rapid removal of recalcitrant organic contaminants from coking wastewater remains a challenge. Powder coke is a burden to coke plant and environment, has the potential as a cost-effective absorbent material. But its absorption capacity is limited by the dense crystalline carbon structure and low surface activity. This study proposes a facile method to fabricate powder coke-derived adsorbent by tuning the surface functional groups. Results revealed that the obtained powder coke-derived adsorbent presented a relatively smooth surface, worm-like pore structure and discernible graphitization degree. The O1S and N1S functional groups were increased from 27.7% to 52.2%. The adsorption of recalcitrant organic contaminants from coking wastewater was increased by 70%, implying significantly by the reduced UV254. The increased N and O-contained functional groups on the surface could introduce hydrophobic force and π-π EDA interactions, which are responsible to the enhanced interactions between powder coke-derived adsorbent and recalcitrant organic contaminants (PAHs and BAD, etc). The engineering aspect of the powder coke-derived adsorbent was discussed in the perspective of recent advances and challenges. This study provides scientific basis for its effective use of powder coke as an adsorbent for tertiary treatment of coke wastewater, so as to achieve the dual purposes of clean production and environmental protection.

116. 题目: Root cellulose drives soil fulvic acid carbon sequestration in the grassland restoration process
文章编号: N20032911
期刊: Catena
作者: Xuejuan Bai, Zehui Guo, Yimei Huang, Shaoshan An
更新时间: 2020-03-29
摘要: Revegetation is an effective means to increase the soil organic carbon (SOC) stock and reverse SOC loss worldwide. Restoration through grasslands has great potential primarily due to the contribution of the root system. However, the impacts of grassland restoration remain uncertain, as current understandings of the direction and magnitude of changes in different SOC fractions and the influence of root properties on SOC are still unclear. To address this problem, we conducted a field study to investigate variations in SOC fractions and root properties under different grassland restoration times (1, 5, 10, 15, 25 and 30 years following restoration) in the Loess Plateau, China. Specifically, we measured fractions of soil labile organic carbon including microbial biomass carbon (MBC) and dissolved organic carbon (DOC) and fractions of soil stable organic C including humus carbon (HS), fulvic acid carbon (FA) and humic acid carbon (HA) in the 1 m soil profile. Furthermore, we evaluated root biomass, root C, root lignin and cellulose as potential drivers of SOC patterns. We found that SOC, soil labile organic C and soil stable organic C fractions generally increased with the revegetation time, except for brief decreases at the 5- and 15-year marks. Across the entire period (year 1 to 30), the proportions of HS and FA to SOC increased by 10.64% and 14.72% at 30 years, respectively, while the ratios of MBC and DOC to SOC were relatively stable. The average SOC accumulation rate was 0.72 Mg ha−1 yr−1 in the 1 m soil profile over the 30-year grassland revegetation period. The average rate of change of FA (0.67 Mg ha−1 yr−1) was higher than that of the HA, HS and soil labile organic C fractions, which indicated that SOC stability increased and SOC accumulation was mainly derived from the enhancement of FA. Decreases in root biomass and cellulose storage drove reductions in SOC fraction stores with soil depth. The root cellulose exerted significant influences on the SOC and SOC fractions, especially on FA (R2 = 0.82, p < 0.01). These findings show that grassland restoration plays an important role in improving and increasing SOC; in particular, the increase of FA results from the augmentations of root cellulose.

117. 题目: Effects of land use on the characteristics and composition of fluvial chromophoric dissolved organic matter (CDOM) in the Yiluo River watershed, China
文章编号: N20032910
期刊: Ecological Indicators
作者: Tiantian Shao, Tao Wang
更新时间: 2020-03-29
摘要: Chromophoric dissolved organic matter (CDOM) is a key indicator of water quality, biogeochemical state and nutrient content in freshwaters. Land use affects the concentration, quality, source, and age of CDOM in rivers. To investigate the characteristics and composition of fluvial CDOM and the effects of land use on carbon components, 37 sites were sampled during May 2017 in the Yiluo River watershed, China. In addition, water parameters, absorption and fluorescence spectral parameters of CDOM were measured in situ and in the lab. Some samples showed atypical CDOM absorption curves with an absorption shoulder at 390 nm. CDOM absorption at 440 nm [aCDOM(440)] was positively correlated with dissolved organic carbon (DOC) and fluorescence intensity (Fn). Fluorescence excitation-emission spectra indicated the presence of strong humic-like and tryptophan-like fluorophores revealing terrestrial, anthropogenic influence. Low recent autochthonous contribution index (BIX) and humification index (HIX) values indicated that autochthonous production was an important contributor to CDOM levels. Cropland-dominated subwatersheds (SWs) exhibited high aCDOM(440), Fn and DOC and forest-dominated SWs showed low CDOM concentration. At the riparian buffer scale, CDOM in the built-up-dominated areas showed the highest CDOM concentration. Moreover, built-up areas greatly influenced the concentrations of DOC and CDOM quantificationally at both the SW and riparian buffer scales; more than 64% of the overall variation in carbon components at the SW scale and 46% of DOC variation at the riparian buffer scale was explained by built-up areas. Overall, the results of our study showed that the properties of fluvial CDOM are dependent on the surrounding land use, further highlighting the importance of land use for CDOM photoreactivity in SWs and riparian buffer zones.

118. 题目: Quantifying the contributions of surface area and redox-active moieties to electron exchange capacities of biochar
文章编号: N20032909
期刊: Journal of Hazardous Materials
作者: Shasha Li, Liming Shao, Hua Zhang, Pinjing He, Fan Lü
更新时间: 2020-03-29
摘要: Redox properties play a critical part in enabling biochar to participate in geochemical redox cycles. To manufacture biochar with targeted redox properties, it is essential to define the correlation of redox properties with the structure and moieties of biochar. However, previous studies focused on moieties, while structural parameters were overlooked. Furthermore, most publications used a single-factor analysis for certain types of moieties with other moieties possibly ignored. Herein, four kinds of representative biomass components, cellulose, lignin, casein, and starch, were pyrolyzed at low, intermediate, and high temperatures to obtain biochar with distinct structures and moieties. Then, the partial least-squares modeling was implemented to evaluate the quantitative contributions of structure and moieties to redox properties with the results obtained by characterizing the biochar. In addition to redox-active moieties, specific surface area was also found to be critical to the redox properties. The cellulose-derived chars exhibited better electron-donating capacities, while the lignin-derived chars exhibited better electron-accepting capacities. The starch-derived chars pyrolyzed at 700℃ possessed both high electron-donating and electron-accepting capacities. The casein-derived biochar exhibited weak redox capacities. These findings show the importance of structural influences on the redox properties and provide feedstock choices when applying and producing biochar with targeted redox properties.

119. 题目: Organic carbon storage and its influencing factors under climate warming of sediments in steppe wetland, China
文章编号: N20032908
期刊: Environmental Science and Pollution Research
作者: Shihai Lyu
更新时间: 2020-03-29
摘要: The effect of climate warming on soil organic carbon (SOC) of sediment in wetlands is important for accurately projecting SOC content. Thus, understanding the mechanism influencing SOC content under climate warming is necessary. Field investigation and a laboratory incubation experiment were conducted in Hulunbeier steppe wetland during 2016 and 2017. Four types of wetland were selected to incubate with ambient temperature and temperature increased by 2.5 °C. The results showed that SOC content was negatively affected by temperature warming. The SOC content reduction in sediment caused by increasing temperature was ranged from − 2.34 to 39.52%. In addition, the content of sand, silt, total phosphorus (TP), calcium phosphate tribasic (Ca-P), total nitrogen (TN), and sediment moisture (MC) should be considered in models of SOC content in steppe wetland. However, it requires further validation, in particular how SOC content varies with warming temperatures, the duration of incubation, and other abiotic and biotic factors. These findings provide evidence that both climate warming and original characteristics of sediment can control the SOC storage dynamics in the steppe wetland.

120. 题目: Enhanced formation of carbonaceous and nitrogenous disinfection byproducts from biofilm extracellular polymeric substances undercatalysis of copper corrosion products
文章编号: N20032907
期刊: Science of the Total Environment
作者: Jun Hu, Chen Wang, Bijuan Shao, Lingxiao Fu, Jianming Yu, Zhimin Qiang, Jianmeng Chen
更新时间: 2020-03-29
摘要: Biofilm formation is ubiquitous on the corroded inner surface of water distribution pipes. Extracellular polymeric substances (EPS) secreted by biofilm microorganisms are nonnegligible precursors of disinfection byproducts (DBPs). The aim was to study the catalysis of copper corrosion products (CCPs, CuO and Cu2+) on the formation of carbonaceous and nitrogenous DBPs (C-DBPs and N-DBPs) with EPS as a precursor. Results indicate that CCPs had a remarkable enhancement on the formation of DBPs, especially N-DBPs. The enhancement by Cu2+ was mainly via homogeneous catalysis initiating from its complexation with EPS, while that by CuO was primarily through heterogeneous catalysis initiating from the polarization of Cl atom in HOCl/OCl−. The enhancement was more evident as pH increased because an alkaline condition favored the electrostatic interactions of CCPs with EPS and HOCl/OCl−. The presence of Br− weakened the enhancement, which may be attributed to that HOBr/OBr− had a much higher reaction rate than HOCl/OCl− towards the low reactive moieties in EPS. Due to more phenolic or unsaturated/conjugated groups, EPS proteins had a higher catalytic formation of DBPs than EPS polysaccharides. Among the major amino acids in EPS proteins for DBPs formation, tyrosine had the highest enhancement on the formation of trihalomethanes, while histidine had the highest catalytic formation of halogenated acetic acids, acetonitriles and acetamides. The study helps to understand the formation of DBPs by the joint actions of EPS and CCPs in drinking water distribution systems.

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