论文检索

主页 | 软件工具 | 课题库 | 公众号
:



总访问量:949841

总访客量:33386

关键词:
Organic Matter |
DOM |
POM |
Soil OM |
Sediment OM |
Organic Carbon |
Organic Nitrogen |
Biomarker |
Humic Substances |
Fulvic Substances |
Humins |
Biochar |
Black Carbon |
GDGT |
Lignin |
Free Radical |
...
最新文章  | 
昨日文章 | 
前日文章
期刊:
Agriculture, Ecosystems & Environment |
Agricultural Water Management |
Applied Geochemistry |
Applied Soil Ecology |
Aquatic Geochemistry |
Atmospheric Research |
Biogeochemistry |
Biogeosciences |
Biology and Fertility of Soils |
Bioresource Technology |
CATENA |
Chemical Engineering Journal |
Chemical Geology |
Chemosphere |
CLEAN - Soil, Air, Water |
Colloids and Surfaces A: Physicochemical and Engineering Aspects |
Deep Sea Research Part II: Topical Studies in Oceanography |
Earth-Science Reviews |
Ecological Engineering |
Ecology Letters |
Ecology |
Ecotoxicology and Environmental Safety |
Environment International |
Environmental Earth Sciences |
Environmental Geochemistry and Health |
Environmental Monitoring and Assessment |
Environmental Pollution |
Environmental Research |
Environmental Science & Technology |
Environmental Science and Pollution Research |
Environmental Science: Processes Impacts |
Environmental Science: Water Research & Technology |
Environmental Toxicology and Chemistry |
Estuarine, Coastal and Shelf Science |
European Journal of Soil Science |
Forest Ecology and Management |
Geochimica et Cosmochimica Acta |
Geoderma |
Geophysical Research Letters |
Global Change Biology |
Global Biogeochemical Cycles |
Groundwater |
Harmful Algae |
International Journal of Coal Geology |
Journal of Environmental Chemical Engineering |
Journal of Environmental Management |
Journal of Environmental Sciences |
Journal of Geophysical Research: Biogeosciences |
Journal of Geophysical Research: Oceans |
Journal of Hazardous Materials |
Journal of Membrane Science |
Journal of Soils and Sediments |
Land Degradation & Development |
Limnology and Oceanography |
Marine Chemistry |
Marine Pollution Bulletin |
Nature Communications |
Nature Geoscience |
Ocean Science Journal |
Oikos |
Organic Geochemistry |
Palaeogeography, Palaeoclimatology, Palaeoecology |
Plant and Soil |
Progress in Oceanography |
Quaternary International |
Science of The Total Environment |
Sedimentary Geology |
Separation and Purification Technology |
Soil and Tillage Research |
Soil Biology and Biochemistry |
Waste Management |
Water Research |
Water, Air, & Soil Pollution |
Wetlands |
...

所有论文

13281. 题目: Soil organic carbon stock on the Majorca Island: Temporal change in agricultural soil over the last 10 years
文章编号: N19053104
期刊: CATENA
作者: José Antonio y Rodríguez Martín, Jorge Álvaro-Fuentes, Jose Luis Gabriel, Carmen Gutiérrez, Nikos Nanos, Miguel Escuer, José Joaquín Ramos-Miras, Carlos Gil, Diana Martín-Lammerding, Rafael Boluda
更新时间: 2019-05-31
摘要: For quite a long time, soil organic carbon stock (SOCS) has reduced from reconverting forest areas into agricultural land or by inadequate agronomic practices. However in recent decades in Mediterranean areas, abandonment of agricultural areas due to lack of economic profits and to promoting tourism has fostered a change in land use that has impacted soil carbon. In line with this, the Majorca Island (Spain) could be a good study area to evaluate temporary changes in carbon stocks in soils in areas with a Mediterranean climate. The present study analysed the spatial distribution of SOCS and evaluated the temporal changes over 11 years in agricultural soils in relation to the influence of land use and land management’. The global carbon budget (estimated at 30 cm depth) on the Majorca Island was estimated at 31.23 Tg C, and showed wide spatial variability. As expected, SOCS was higher in the forest areas of the Tramuntana Mountain Range (>100 Mg ha−1), while the lowest contents were found in agricultural use (79.3 Mg ha−1), located mainly in the centre and south of this island.The total C stored from 2006 to 2017 increased by 2.62 Tg C (15%) in agricultural areas on the island. We noted a major increase in SOCS in the agricultural zones on mountain slopes (>2-fold higher), associated with abandoned crops in terrace cultivation, but grassland systems also increased. Nonetheless, the present study shows a sharp drop in SOCS in the centre and south of this island. This decrease was more pronounced in annual crops (−14.5%), which could be attributed to intensive soil management and increased irrigated land. Land abandonment has been indicated as the main potential to carbon sequestration in soil, but this potential for carbon sequestration is a finite process. Certain changes in agricultural practices on Majorca, and in rural Mediterranean areas in general, are necessary to avoid carbon loss in cropland soils. Adoption of conservation agriculture practices, e.g. cover crops, crop rotation, organic additions and reduced tillage techniques, can help increase SOC levels in rural Mediterranean areas.
图文摘要:

13282. 题目: Degradation of tris-(2-chloroisopropyl) phosphate via UV/TiO2 photocatalysis: kinetic, pathway, and security risk assessment of degradation intermediates using proteomic analyses
文章编号: N19053103
期刊: Chemical Engineering Journal
作者: Xiaolong Yu, Hua Yin, Jin Shao Ye, Hui Peng, Guining Lu, Zhi Dang
更新时间: 2019-05-31
摘要: As a class of emerging organic contaminants (EOCs), organophosphate flame retardants (OPFRs) have been raising concern due to their persistence, bioaccumulation and toxicity. Therefore, it is urgent need to develop environmental-friendly and high-efficient techniques to remove OPFRs. The degradation kinetics and mechanism of tris-(2-chloroisopropyl) phosphate (TCPP), a representative OPFRs, by UV/TiO2 photocatalytic degradation were explored in current research. It was found that degradation reaction was well documented by first-order kinetics with a kobs of 0.3146 min−1, and hydroxyl radical was identified as a dominating contributor for the TCPP elimination. Simultaneously, six steady intermediate products were generated with the release of Cl and PO43− as photocatalytic reaction further proceeded. The degradation efficiency can be interfered by natural organic matters, anions and pH value, implying that an incomplete mineralization of TCPP could be ubiquitous in heterogeneous water matrix. Combining the proteomics analysis with KEGG metabolism networks analysis, the process of transmembrane transport and energy generation in Escherichia coli altered by intermediates has proved that the intermediates could be transported and utilized through cellular metabolism. Moreover, the diminution of stress resistance suggested that the toxicity of degradation products through UV/TiO2 photocatalytic degradation was lower than that of intact TCPP. To sum up, environmental safety of degrading intermediate products and the satisfactory detoxification effect of TCPP were identified under appropriate mineralization, indicating that UV/TiO2 photocatalysis technique was safe and high-efficient for TCPP control.
图文摘要:

13283. 题目: Interaction with low molecular weight organic acids affects the electron shuttling of biochar for Cr(VI) reduction
文章编号: N19053102
期刊: Journal of Hazardous Materials
作者: Zibo Xu, Xiaoyun Xu, Xinyi Tao, Chengbo Yao, Daniel C.W. Tsang, Xinde Cao
更新时间: 2019-05-31
摘要: Biochar can act as “electron shuttle” in soil redox reactions. It is possible that biochar accepts the electrons from low molecular weight organic acids (LMWOAs) in soil and then transfer them to the acceptors, e.g., Cr(VI). This study evaluated the interaction between seven soil LMWOAs and peanut shell biochar (BC) as well as its effect on the electron shuttling of biochar for Cr(VI) reduction. Both redox reactions and sorption process occurred during the interaction of biochar and LMWOAs, which altered the contents of Cr(VI) reduction-relevant groups (i.e., C–O and –C = O) on the surface of biochar. The redox reactions were more important to the electron transfer between biochar produced at 400℃ (BC400) and LMWOAs due to the repeated cycle of reduction-oxidation of surface functional groups. The reduction rate of Cr(VI) by LMWOAs mediated by BC400 was 1.10-7.09 × 10-3 h-1, among which tartaric acid had the best reduction efficiency due to its highest reducing capability. For biochar produced at 700℃ (BC700), the sorption process of LMWOAs was the key factor to the direct electron shuttling process through the conjugated structure of biochar. The reduction rate of Cr(VI) by LMWOAs mediated by BC700 was significantly higher and ranged 7.40-864 × 10-3 h-1, with the oxalic acid having the best reduction efficiency due to its highest sorption capacity by BC700. The results obtained from this study can help to establish the linkage between biochar and LMWOAs in soil electron network, which better explains the multifunctional roles of biochar during the redox processes such as Cr(VI) reduction in soil.
图文摘要:

13284. 题目: Organic matter variations and links to climate across the early Toarcian oceanic anoxic event (T-OAE) in Toyora area, southwest Japan
文章编号: N19053101
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: David B. Kemp, Viktória Baranyi, Kentaro Izumi, Roger D. Burgess
更新时间: 2019-05-31
摘要: Marked climate warming during the early Toarcian oceanic anoxic event (T-OAE, ~182 Ma) has been shown to have had a significant effect on the global carbon cycle and biosphere. There is also emerging evidence that a primary short-term consequence of this warming was a marked increase in hydrological cycling. In this study, we have investigated local environmental responses to T-OAE climate change by conducting a palynofacies analysis through an expanded Panthalassic margin record of the event exposed in southwestern Japan (Nishinakayama Formation, Toyora area). Palynomorphs are poorly preserved and rare in the studied interval. A pronounced increase in terrestrial phytoclast abundance coeval with the peak of the T-OAE can be linked to increased fluvial supply driven by enhanced hydrological cycling that occurred in response to early Toarcian warming. Broader scale trends in phytoclast abundance through the studied interval may be linked to longer-term sea-level changes. Nitrogen-isotopes, commonly used to elucidate basin redox changes, are found to correlate with changes in the relative abundance of phytoclasts. In contrast, carbon-isotope data are probably not significantly influenced by changes in organic matter type through the succession. However, thermal maturity indicators demonstrate that the succession is overmature, and this likely suppresses the magnitude of the well-known T-OAE carbon-isotope excursion in this succession.

13285. 题目: Impact of light and Suwanee River Fulvic Acid on O 2 and H 2 O 2 Mediated Oxidation of Silver Nanoparticles in Simulated Natural Waters
文章编号: N19053011
期刊: Environmental Science & Technology
作者: Hongyan Rong, Shikha Garg, T. David Waite
更新时间: 2019-05-30
摘要: In this work, we investigate the impact of natural organic matter (NOM) and light on silver nanoparticle (AgNP) dissolution kinetics with particular emphasis on determining the (i) mechanism via which NOM affects the oxidative dissolution of AgNPs, (ii) the role of photogenerated organic radicals and reactive oxygen species (ROS) in oxidative dissolution of AgNPs, and (iii) the mechanism of formation of AgNPs in NOM solution under dark and irradiated conditions. We measured the oxidation of citrate stabilized AgNPs by O2 and hydrogen peroxide (H2O2) in the dark and in irradiated Suwannee River fulvic acid (SRFA) solutions at pH 8.0. Results show that the reactivity of AgNPs toward O2 and H2O2 in the dark decreased in the presence of SRFA as a result of blocking of AgNP surface sites through either steric or electrostatic effects. Irradiation promoted dissolution of AgNPs by O2 and H2O2 in the presence of low concentrations (≤20 mg·L–1) of SRFA as a result of contribution from photogenerated H2O2 formed on irradiation of SRFA as well as photofragmentation of AgNPs. Furthermore, our results show that photogenerated superoxide can induce formation of AgNPs by reducing Ag(I) ions. Based on our experimental results, we have developed a kinetic model to explain AgNP transformation by O2 and H2O2 in the dark and in irradiated SRFA solutions with this model of use in predicting the transformation and fate of AgNPs in natural waters.

13286. 题目: Dissolved organic matter composition in a marsh‐dominated estuary: Response to seasonal forcing and to the passage of a hurricane
文章编号: N19053010
期刊: Journal of Geophysical Research: Biogeosciences
作者: Maria L. Letourneau, Patricia M. Medeiros
更新时间: 2019-05-30
摘要: Dissolved organic matter (DOM) is a large and complex mixture of compounds with source inputs that differ with location, season and environmental conditions. Here, we investigated drivers of DOM composition changes in a marsh‐dominated estuary off the southeastern U.S. Monthly water samples were collected at a riverine and estuarine site from September 2015 to September 2016, and bulk, optical, and molecular analyses were conducted on samples before and after dark incubations. Results showed that river discharge was the primary driver changing the DOM composition at the mouth of the Altamaha River. For discharge higher than ~ 150 m3 s‐1, DOC concentrations and the terrigenous character of the DOM increased approximately linearly with river flow. For low discharge conditions, a clear signature of salt marsh‐derived compounds was observed in the river. At the head of Sapelo Sound, changes in DOM composition were primarily driven by river discharge and possibly by summer algae blooms. Microbial consumption of DOC was larger during periods of high discharge at both sites, potentially due to the higher mobilization and influx of fresh material to the system. The Georgia coast was hit by Hurricane Matthew in October 2016, which resulted in a large input of carbon to the estuary. The DOC concentration was ~ 2 times higher and DOM composition was more aromatic with a stronger terrigenous signature compared to the seasonal maximum observed earlier in the year during peak river discharge conditions. This suggests that extreme events notably impact DOM quantity and quality in estuarine regions.

13287. 题目: Evaluation of bacterial glycerol dialkyl glycerol tetraether and 2H-18O biomarker proxies along a Central European topsoil transect
文章编号: N19053009
期刊: Biogeosciences
作者: Johannes Hepp, Imke K. Schäfer, Verena Lanny, Jörg Franke, Marcel Bliedtner, Kazimierz Rozanski, Bruno Glaser, Michael Zech, Timothy I. Eglinton, and Roland Zech
更新时间: 2019-05-30
摘要: Molecular fossils, like bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs), and the stable isotopic composition of biomarkers, such as δ2H of leaf wax-derived n-alkanes (δ2Hn-alkane) or δ18O of hemicellulose-derived sugars (δ18Osugar) are increasingly used for the reconstruction of past climate and environmental conditions. Plant-derived δ2Hn-alkane and δ18Osugar values record the isotopic composition of plant source water (δ2H/δ18Osource-water), which usually reflects mean annual precipitation (δ2H/δ18Oprecipiation), modulated by evapotranspirative leaf water enrichment and biosynthetic fractionation. Accuracy and precision of respective proxies should be ideally evaluated at a regional scale. For this study, we analysed topsoils below coniferous and deciduous forests, as well as grassland soils along a Central European transect in order to investigate the variability and robustness of various proxies, and to identify effects related to vegetation. Soil pH-values derived from brGDGTs correlate reasonably well with measured soil pH-values, but systematically overestimate them (ΔpH = 0.6 ± 0.6). The branched vs. isoprenoid tetraether index (BIT) can give some indication whether the pH reconstruction is reliable. Temperatures derived from brGDGTs overestimate mean annual air temperatures slightly (∆TMA = 0.5 °C ± 2.4). Apparent isotopic fractionation (εn-alkane/precipitation and εsugar/precipitation) is lower for grassland sites than for forest sites due to "signal damping", i.e. grass biomarkers do not record the full evapotranspirative leaf water enrichment. Coupling δ2Hn-alkane with δ18Osugar allows to reconstruct the stable isotopic composition of the source water more accurately than without the coupled approach (Δδ2H = ~-21 ‰ ± 22 and Δδ18O = ~-2.9 ‰ ± 2.8). Similarly, relative humidity during daytime and vegetation period (RHMDV) can be reconstructed using the coupled isotope approach (ΔRHMDV = ~-17 ± 12). Especially for coniferous sites, reconstructed RHMDV values as well as source water isotope composition underestimate the measured values. This can be likely explained by understory grass vegetation at the coniferous sites contributing significantly to the n-alkane pool but only marginally to the sugar pool in the topsoil. The large uncertainty likely reflect the fact that biosynthetic fractionation is not constant, as well as microclimate variability. Overall, GDGTs and the coupled δ2Hn-alkane18Osugar approach have great potential for more quantitative paleoclimate reconstructions.

13288. 题目: Biochar from extracted marine Chlorella sp. residue for high efficiency adsorption with ultrasonication to remove Cr(VI), Zn(II) and Ni(II)
文章编号: N19053008
期刊: Bioresource Technology
作者: Muhammad Amin, Pakamas Chetpattananondh
更新时间: 2019-05-30
摘要: The biochar BC-450 derived from the extracted marine Chlorella sp. residue (EMCR) had high surface area (266 m2/g) and was rich in ash and O-functional groups. Its characteristics are suitable for heavy metal adsorption. The adsorption parameters were investigated to optimize the removal efficiency of Cr(VI), Zn(II) and Ni(II) from aqueous solution by conventional adsorption (CA) and by ultrasonication adsorption (UA). The adsorption was fit by Langmuir isotherm and by pseudo-second-order model. The equilibrium times were 10, 8, 15 minutes and 40, 60, 80 minutes for removal of Cr(VI), Zn(II) and Ni(II) with UA and CA, respectively. The maximum adsorption capacities of Cr(VI), Zn(II) and Ni(II) for CA and UA were 15.94, 17.62 and 24.76 mg/g and 18.86, 21.31 and 27.45 mg/g, respectively. UA presented 1.1-1.3 times greater removal efficiencies than CA in much shorter time. The EMCR is a promising feedstock for producing low cost and high efficiency adsorbents.
图文摘要:

13289. 题目: Extracellular polymeric substances extraction and recovery from anammox granules: Evaluation of methods and protocol development
文章编号: N19053007
期刊: Chemical Engineering Journal
作者: Cuijie Feng, Tommaso Lotti, Yuemei Lin, Francesca Malpei
更新时间: 2019-05-30
摘要: Selection of appropriate extraction methods of extracellular polymeric substances (EPSs) is crucial, affecting the yield, composition and the properties of EPSs. However, there is still a lack of standard methods for EPS extraction. In this study, seven methods were compared to extract EPS from anaerobic ammonium oxidation (anammox) granules, and the effectiveness and cell lysis of these methods were evaluated. The heating-Na2CO3 based method obtained a higher EPS yield with limited cell lysis. Proteins (PN) and polysaccharides (PS) were predominant in extractable EPSs. Particularly, PN-related substances were substantially enriched and high PN/PS ratios resulted in most methods. Different methods resulted in EPSs with a different size distribution. By analysis of Attenuated total reflectance-Fourier transform infrared spectra (ATR-FTIR), amide- and polysaccharide-associated bands were dominant. ATR-FTIR and fluorescence density of excitation-emission matrix spectra indicated EPS compositions and structures varied with the extraction methods. Moreover, the extraction/recovery protocol based on the heating-Na2CO3 method was remarkably improved, by varying heating time and using a centrifugal filter device with membrane (CFDM) to replace concentration and purification steps. Eventually, the thermal method with an extraction time of 45 mins was identified to be most effective. The application of CFDM was demonstrated as an alternative approach to concentrate and purify for EPS recovery. To our best knowledge, this is the first original study to systematically evaluate the different EPS extraction methods from anammox granules.
图文摘要:

13290. 题目: Risk evaluation of biochars produced from Cd-contaminated rice straw and optimization of its production for Cd removal
文章编号: N19053006
期刊: Chemosphere
作者: Zhengtao Shen, Xiaoliang Fan, Deyi Hou, Fei Jin, David O'Connor, Daniel C.W. Tsang, Yong Sik Ok, Daniel S. Alessi
更新时间: 2019-05-30
摘要: Based on the “waste-treat-waste” concept, biochars were produced from cadmium (Cd)-contaminated rice straw (CRSBs) at 300, 500, and 700 °C (CRSB300, CRSB500, and CRSB700). The risks of the Cd remaining in CRSBs were evaluated and the optimal biochar pyrolysis temperature for Cd removal was investigated. It was observed that 41% of the total Cd in the raw rice straw was exchangeable, which may poses significant risks to crops and humans. Pyrolyzing at 300 °C did not significantly alter the Cd fractions, while the exchangeable fraction of Cd greatly dropped to 5.79% at 500 °C and further to 2.12% at 700 °C. Increasing the highest pyrolysis temperature resulted in CRSB with higher pH values, greater surface area, and smaller pore sizes, thus providing more rapid and efficient removal of Cd from aqueous solutions. For Cd removal tests, increasing pyrolysis temperature (300–700 °C) increased the total (24.8–55.1 mg/g) and non-exchangeable (18.9–52.8 mg/g) Cd concentrations immobilized on the CRSBs and significantly decreased the exchangeable Cd fraction (23.7%–4.85%). It is suggested based on the study from aqueous solutions that CRSB700 was the most suitable for the remediation of Cd contaminated soil on site due to the lowest risks of remained Cd from feedstock, fastest and highest Cd removal, and most stable immobilization of Cd.

13291. 题目: Ozonation reactivity characteristics of dissolved organic matter in secondary petrochemical wastewater by single ozone, ozone/H2O2, and ozone/catalyst
文章编号: N19053005
期刊: Chemosphere
作者: Liya Fu, Changyong Wu, Yuexi Zhou, Jiane Zuo, Guangqing Song, Yu Tan
更新时间: 2019-05-30
摘要: Advanced oxidation methods (e.g., ozonation systems) are used for control of recalcitrant pollutants in secondary petrochemical wastewater. For the selection of the optimal wastewater treatment method, we compared the reactivity characteristics of dissolved organic matter (DOM) in three common ozone treatment processes: single ozone, ozone/H2O2, and ozone/catalyst. The raw and ozonated DOM were fractionated into six fractions using ion exchange resins. Fluorescence spectroscopy and size exclusion chromatography were employed to characterize the fractions. The results showed that the single ozone system transformed hydrophobic components into hydrophilic components, but exhibited low mineralization ability. By contrast, the increase in hydrophilic acid fractions transformed from other fractions in the ozonation process were further mineralized in the ozone/H2O2 and ozone/catalyst systems. Ozone/H2O2 preferentially reduced hydrophobic bases, whereas ozone/catalyst preferentially reduced hydrophilic neutral components. However, ozone/H2O2 exhibited low selectivity in degrading organic compounds of different molecular weights. The highest total organic carbon (TOC) removal efficiency was achieved in the ozone/catalyst system, which promoted the transformation from fulvic acid- and humic acid-like substances into aromatic proteins and soluble microbial by-product-like substances. The single ozone system transformed high-molecular-weight compounds into low-molecular-weight compounds, resulting in an unsatisfactory TOC removal efficiency. By contrast, the ozone/catalyst system selectively removed the residual low-molecular-weight compounds in the reaction with ozone. This might have contributed to the high TOC removal efficiency of the ozone/catalyst treatment. These results can be used by other researchers and engineers to inform the selection of optimal ozone treatment based on wastewater characteristics.
图文摘要:

13292. 题目: Characterisation of dissolved organic matter in fermentation industry effluents and comparison with model compounds
文章编号: N19053004
期刊: Chemosphere
作者: Jeraz Cooper, Alice Antony, Audrey Luiz, John Kavanagh, Amir Razmjou, Vicki Chen, Greg Leslie
更新时间: 2019-05-30
摘要: Advanced organic characterisation methods were used to investigate the suitability of lab-based model compounds as surrogates to mimic the dissolved organic matter (DOM) of both first and second generation fermentation industry effluents. Comparisons to both humic acid and synthetic melanoidin revealed the limitations of using these model organic compounds in treatment studies of biorefinery effluent. Rapid resin fractionation (RRF) of effluent from yeast cultivated on molasses suggests that 64% of the dissolved organic matter is present in the form of very hydrophobic acid (VHPhoA) compounds. Molecular weight distribution by size exclusion chromatography (LC-OCND) and fluorophore specific intensity by fluorescence excitation and emission matrix (FEEM) of the yeast effluent was comparable to signatures from humic acid. This indicates that humic acid would be a suitable model compound for oxidation, adsorption and filtration studies. Differences among the fermentation industry effluents were found to be inherently dependent on both the biochemistry of yeast and processes used. RRF and FEEM spectra of effluent from bioethanol production on cellulosic feed highlighted a preponderance of neutral compounds with fluorophore specific intensity characteristic of non-humic compounds with a higher fraction of neutral compounds (41%) relative to VHPhoA (38%), SHPhoA (16%) and HPhi (5%) moieties. Findings were not consistent with commercial humics, synthetic melanoidins or other cellulosic and lignocellulosic based effluents from Kraft and Thermomechanical pulp mills since the actual pollutants are heavily dependent on the pre-treatment process. This suggests further work is required to develop a model compound for treatment studies of effluent from second generation bio-refineries.
图文摘要:

13293. 题目: Disentangling the effects of parent material and litter input chemistry on molecular soil organic matter composition in converted forests in Western Europe
文章编号: N19053003
期刊: Organic Geochemistry
作者: Olaf Brock, Annemieke Kooijman, Klaas G.J. Nierop, Bart Muys, Karen Vancampenhout, Boris Jansen
更新时间: 2019-05-30
摘要: By storing carbon in the soil, forests contribute to climate change mitigation. Edaphic (soil related) factors, such as soil pH, as well as tree species affect forest carbon cycles, but are difficult to disentangle. We studied how conversion of deciduous stands to mono-culture spruce plantations affected the soil organic matter (SOM) composition along a lithological gradient in the Mullerthal (Luxembourg) and Gaume (south-east Belgium) regions. Parent materials in these regions range from decalcified sands to calcareous marls. A twin plot setup of adjacent deciduous and coniferous stands on the same parent material was used to evaluate the effect of edaphic factors versus litter input differences on SOM composition and soil organic carbon (SOC) stocks. Lignin and cutin/suberin molecular proxies were identified with thermally assisted hydrolysis and methylation (THM), to distinguish litter sources (coniferous vs deciduous and leaf litter vs roots) in the studied stands. In this study, SOC stocks were influenced more by parent material than by forest type. Lignin yield, composition and degradation state were influenced both by litter input chemistry and edaphic context. There appear to be important interaction effects between the two, as the relative importance of parent material and litter quality was site specific. We therefore advice that carbon stock models include data on both vegetation history as well as edaphic context.
图文摘要:

13294. 题目: Dewatering performance of sewage sludge under pretreatment with modified corn-core powder
文章编号: N19053002
期刊: Science of The Total Environment
作者: Zhiying Guo, Liping Ma, Quxiu Dai, Jing Yang, Ran Ao, Lichun Wang
更新时间: 2019-05-30
摘要: The water retained inside the sludge flocs is the bottleneck for the dehydration of sewage sludge, which hindered the following treatment. In this study, corn core powder was modified (MCCP) using sodium hydroxide (NaOH) and cationic surfactant cetyltrimethylammonium bromide (CTMAB) to break the structure of extracellular polymeric substances (EPS) and cell membrane for enhancing the dewaterability of sewage sludge. The dewatering performance, the properties of the treated sludge, the composition and distribution of EPS were investigated to discuss the dewatering mechanism of sludge. Adding 20% DS (mass of dry solids in sludge) of MCCP reduced the moisture content (MC) and the specific resistance of filtration (SRF) of the sludge by 40% and 55%, respectively. Then, correlation analyses were performed between dewatering indices of sludge and sludge properties. A multiple linear regression model was established which indicated the relationship between MC and the key factors reflecting sludge dewaterability, demonstrating that larger particle size of sludge flocs and more total dissolved solids in filtrate may be propitious to reduce content of bound water in sludge.
图文摘要:

13295. 题目: Photochemical production of hydroxyl radical from algal organic matter
文章编号: N19053001
期刊: Water Research
作者: Xi-Zhi Niu, Jean-Philippe Croué
更新时间: 2019-05-30
摘要: Photochemical production of hydroxyl radical (·OH) from algal organic matter (AOM) collected from Lake Torrens in South Australia was examined using a sunlight simulator. The two AOM isolates featured lower molecular weight, lower chromophoric content, and lower SUVA254 (0.7 and 0.9, L mgC−1 m−1) than the reference Suwannee River hydrophobic acid (SR-HPO), they had considerably higher apparent quantum yields (ϕNOMOH, 3.03 × 10−5 and 2.18 × 10−5) than SR-HPO (0.84 × 10−5). Fluorescence excitation-emission matrix (FEEM) showed that the major components in the AOM were aromatic protein-like and soluble microbial substances. Unique formulas of the two AOM isolates as compared to SR-HPO were revealed using FTICR-MS and classified into four areas, namely protein-like molecules with low O/C (H/C > 1.5, O/C: 0.2–0.4), lignin-derived moieties with low O/C (H/C:1.0–1.5, O/C: 0.1–0.3), protein-like molecules with high O/C (H/C > 1.5, O/C: 0.5–0.7), and carbohydrate derivatives (H/C > 1.5, O/C > 0.7). These unique AOM moieties characterised utilizing FEEM and FTICR-MS were tentatively postulated to contribute to the high ϕNOMOH. To the best of our knowledge, this is the first study performed to both evaluate natural AOM as an efficient photosensitiser of ·OH and propose AOM moieties responsible for the high ϕNOMOH.
图文摘要:

13296. 题目: Climate Smart Agriculture practices improve soil organic carbon pools, biological properties and crop productivity in cereal-based systems of North-West India
文章编号: N19052918
期刊: CATENA
作者: H.S. Jat, Ashim Datta, Madhu Choudhary, P.C. Sharma, A.K. Yadav, Vishu Choudhary, M.K. Gathala, M.L. Jat, A. McDonald
更新时间: 2019-05-29
摘要: Intensive tillage coupled with crop residue burning in rice-wheat (RW) system is a serious issue that causes soil degradation and environmental pollution. Soil organic carbon (SOC) is one of the main indicators of soil health and system's sustainability. Zero-tillage has been widely recommended as an alternative for improving carbon sequestration in soil under different ecologies. But the SOC sequestration is very inconsistent and varied as it depends on the crop management practices. This study was performed in the western Indo-Gangetic plains (IGP) of India where RW system contributes 40% to the total country's food grain basket; however there exists issue of its sustainability because of declining SOC coupled with open field crop residue burning. Therefore, we evaluated the effects of different management scenarios (Sc) namely Sc1 (conventional till rice-wheat cropping system; business as usual), Sc2 (partial climate smart agriculture (CSA)-based rice-wheat-mungbean system), Sc3 (CSA-based rice-wheat-mungbean system), and Sc4 (CSA-based maize-wheat-mungbean system) on SOC pools and biological properties after 4 crop cycles (year 2009–2013). Soil samples were collected from surface and sub surface layers (0–15 and 15–30 cm soil depth) after rice harvesting in 2013. Results showed that the SOC stock at surface layer was higher by 70% with Sc4 than Sc1 (16.2 Mg C ha−1) (P < 0.05). All the forms of carbon in different pools were higher (P < 0.05) with Sc4 and Sc2 over Sc1 at 0–15 and 15–30 cm soil depths, respectively. At surface soil SOC pools were found in order of Sc4 > Sc3 > Sc2 > Sc1 (P < 0.05). Higher lability index (LI) (2.1) and stratification ratio (SR) (2.5) of organic carbon were observed in CSA-based systems (Sc2 and Sc4). At surface layer (0–15 cm) the CSA- based scenarios (mean of Sc2, Sc3 and Sc4) showed higher (P < 0.05) enzyme activities viz. dehydrogenase (641 μgTPF g−1 24 h−1) and alkaline phosphatase (158 μg p-nitrophenol g−1), and microbial biomass carbon (MBC) (787 μg g−1) and microbial biomass nitrogen (MBN)(98 μg g−1) compared with Sc1. Higher value of the basal soil respiration (34%) was also observed with CSA-based scenarios (Sc2, Sc3, Sc4). Surface soil layer showed maximum counts of fungi, bacteria and actinomycetes in Sc4. MBC, fungal population and SOC were the most sensitive biological soil parameters identified through principal component analysis (PCA) which can be used for soil quality assessment. Therefore, medium term adoption of climate smart agricultural practices involving zero-tillage, crop establishment, residue management and crop diversification in rice-wheat system can significantly improve the systems productivity by improving SOC and soil biological quality.

13297. 题目: Multianalytical characterization of biochar and hydrochar produced from waste biomasses for environmental and agricultural applications
文章编号: N19052917
期刊: Chemosphere
作者: Eren Taskin, Carolina de Castro Bueno, Ignazio Allegretta, Roberto Terzano, Andrè Henrique Rosa, Elisabetta Loffredo
更新时间: 2019-05-29
摘要: Biochar (BC) and hydrochar (HC) are solid by-products obtained from various types of biomasses through the processes of pyrolysis and hydrothermal carbonization, respectively. Both BC and HC represent a sustainable solution for carbon sequestration and can be used as soil amendments or sorbents for organic and inorganic pollutants. However, the properties of BC and HC largely depend on feedstock and production parameters, which significantly affect their proper use. A detailed characterization of these materials is therefore needed to assess their suitability for environmental and/or agricultural applications. In this work, two BC samples and two HC samples were characterized with a multianalytical approach, including total reflection X-ray fluorescence (TXRF) spectroscopy, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analyses (TG), and pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS). By comparing BC and HC data, HC showed a higher content of mineral elements, including important plant nutrients and potentially toxic elements. HC produced from solid urban wastes contained also some potentially toxic organic molecules, like chlorinated aromatic compounds. BC samples were characterized by a higher porosity and hydrophobicity than HC, thus being potentially more suitable for the sorption of organic pollutants. HC samples showed a higher content of cellulose and hemicellulose, resulting in a more hydrophilic but less thermally stable material than BC. In conclusion, both BC and HC have interesting properties for environmental and agricultural applications but careful selection of feedstock is needed, especially for HC production.

13298. 题目: The impact of environmental parameters on the conversion of toluene to CO2 and extracellular polymeric substances in a differential soil biofilter
文章编号: N19052916
期刊: Chemosphere
作者: Achinta Bordoloi, Daniel J. Gapes, Peter A. Gostomski
更新时间: 2019-05-29
摘要: The fraction of pollutant converted to CO2 versus biomass in biofiltration influences the process efficacy and the lifetime of the bed due to pressure drop increases. This work determined the relative quantitative importance and potential interactions between three critical environmental parameters: toluene concentration (Tol), matric potential ψ and temperature (T) on % CO2, elimination capacity (EC) and the production rate of non-CO2 products. These parameters are the most variable in typical biofilter operation. The data was fit to a non-linear model of the form yaTolbTcψd. A rigorous carbon balance (100.5 ± 7.0%) tracked the fate of degraded toluene as CO2 and non-CO2 carbon endpoints. The % CO2 mineralization varied from (34–91%) with environmental parameters: temperature (20–40 °C), matric potential, (−10 to −100 cmH2O) and residual toluene, (20–180 ppm). The highest conversion to CO2 was at the wettest conditions (−10 cmH2O) and lowest residual toluene concentration (18 ppm). Matric potential had twice the impact of toluene concentration on % CO2, while temperature had less impact. The elimination capacity varied from 11 to 50 gC⋅m−3h−1 and was highest at 40 °C, the wettest conditions with limited impact by toluene concentrations. Temperature increased the EC and non-CO2 production rates strongly while matric potential and toluene concentration had less influence (4x - 10x less). This study illustrated the quantitative significance and simultaneous interaction between critical environmental parameters on carbon endpoints and biofilter performance. This kind of multivariable parameter study provides valuable insights which can address performance and clogging issues in biofilters.
图文摘要:

13299. 题目: Pyrolysis-temperature depended quinone and carbonyl groups as the electron accepting sites in barley grass derived biochar
文章编号: N19052915
期刊: Chemosphere
作者: Yue Zhang, Xiaoyun Xu, Pengyu Zhang, LingZhao, Hao Qiu, Xinde Cao
更新时间: 2019-05-29
摘要: Biochar has been proven to possess the electron transfer property that can participate in the biogeochemical redox reaction in the environment. In this study, the electron accepting capacities (EACs) of the barley grass biochars produced at the various temperatures from 350 °C to 800 °C were investigated. The EAC values were in the range of 0.27–0.72 mmol e (g biochar)−1and showed increase as the pyrolysis temperature increased from 350 °C to 450 °C, slight decrease with temperature increasing from 450 °C to 500 °C, and then increase again from 650 °C to 800 °C. The O-containing groups were the EAC moieties identified by temperature programmed desorption coupled with mass spectroscopy (TPD-MS) and fourier transform infrared spectroscopy (FTIR) and carbonyl and quinone were the main EAC moieties, accounting for 75.4%–95.7% as the pyrolysis temperature increased from 350 °C to 800 °C. Overall, carbonyl and quinone determined the EACs properties of biochar which were affected by the pyrolysis temperature. The results will help us to develop biochar with controlled electron accepting property for specific environmental applications.
图文摘要:

13300. 题目: Long term effects of Pb2+ on the membrane fouling in a hydrolytic-anoxic-oxic-membrane bioreactor treating synthetic electroplating wastewater
文章编号: N19052914
期刊: Chemosphere
作者: Qiong Wang, Qinxue Wen, Zhiqiang Chen
更新时间: 2019-05-29
摘要: Long-term effects of Pb2+ on the operating performance and membrane fouling of two hydrolytic-anoxic-oxic-membrane bioreactors treating synthetic electroplating wastewater were investigated. The COD, NH4+-N and TN removal efficiencies decreased by 5.5%, 10.4% and 7.9% with long-term exposure of 2 mg L−1 Pb2+, while serious decreases achieved 25.4%, 35.0% and 26.2% with 6 mg L−1 Pb2+ exposure, respectively. 2 mg L−1 Pb2+ mitigated the cake layer fouling rate by 25.4% but increased the pore blocking rate by 69.1%, which was contributed by the increase of low and moderate molecular weight (MW) components in the soluble and colloidal foulants (SCFs). 6 mg L−1 Pb2+ accelerated the cake layer fouling rate by 101.1%, but mitigated the pore blocking rate by 6.4% due to the increase of high MW SCFs (especially polysaccharides). Thermodynamic analyses showed that Pb2+ regulated the concentration and protein/polysaccharide ratio of loosely bound extracellular polymeric substances, thus changing the flocs hydrophobicity and aggregation capacity, leading the cake layer fouling rate variation.

 共 17423 条记录  本页 20 条  本页从 13281-13300 条  665/872页  首页 上一页  660 661 662 663 664 665 666 667 668 669 670  下一页  末页   

本数据库数据来源自各期刊,所有权归属各期刊。数据仅供分享学习,不作商业用途,特此申明。