论文检索

主页 | efc软件 | 课题库 | 公众号
:



总访问量:406152

总访客量:22002

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

8061. 题目: Estimating CDOM concentration in highly turbid estuarine coastal waters
文章编号: N18081512
期刊: Journal of Geophysical Research: Oceans
作者: Jun Zhao, Wenxi Cao, Zhantang Xu, Bin Ai, Yuezhong Yang, Guangzhen Jin, Guifen Wang, Wen Zhou, Yong Chen, Haiyun Chen, Zhaohua Sun
更新时间: 2018-08-15
摘要: We proposed a support vector machine (SVM) algorithm to retrieve colored dissolved organic matter (CDOM) concentration (using ag(443) as a proxy) in the highly turbid Pearl River estuary (PRE). Two band ratios, namely Rrs(443)/Rrs(547) and Rrs(488)/Rrs(547), were used as inputs. Comparisons between the estimated and measured ag(443) illustrated high accuracy of the SVM algorithm, yielding R2s of 0.98 and 0.89, mean absolute percentage errors (MAPEs) of 5.18% and 13.1%, and root mean square deviations (RMSDs) of 0.012 and 0.034 m‐1 for the training and validation datasets, respectively. The SVM algorithm was also evaluated against existing ones for the study area and gave the best accuracy with a R2 of 0.9, a MAPE of 10.23%, and a RMSD of 0.025 m‐1. The diurnal dynamics of CDOM in the PRE was revealed showing complicated variations and influenced by the combined effects of wind, tide, circulation, and river discharge. As for remote sensing applications, the SVM‐based CDOM product exhibited great potential to trace the Pearl River plume and the satellite‐derived plume area agreed well with the FVCOM model simulation result. SVM is an accurate and fast tool for retrieving CDOM concentration, especially in highly turbid estuarine coastal waters, and thus, river plume dynamics can be traced.

8062. 题目: Joint effects of extrinsic biophysical fluxes and intrinsic hydrodynamics on the formation of hypoxia west off the Pearl River Estuary
文章编号: N18081511
期刊: Journal of Geophysical Research: Oceans
作者: Zhongming Lu, Jianping Gan, Minhan Dai, Hongbin Liu, Xiaozheng Zhao
更新时间: 2018-08-15
摘要: Using field measurements and a process‐oriented three‐dimensional coupled physical‐biogeochemical numerical model, we investigated the physical and biogeochemical processes governing the bottom hypoxic zone on the western shelf off the Pearl River Estuary. The intensity and area of the hypoxia grew with increasing total nutrient input from the Pearl River that has increased continuously in recent decades. The hypoxic zone was formed and maintained largely associated with the stable water column where the stability was provided simultaneously by wind stress and freshwater discharge, favourable local hydrodynamics for flow convergence, and westward organic matter transport. Wind stress altered the stratification, while freshwater discharge changed the stratification and baroclinic velocity shear simultaneously. Two‐layered flow with a cyclonically‐rotating current around a salient edge of the western shelf off the estuary hydrodynamically enhanced the local convergence, allowing sufficient residence time for the remineralization of organic matter produced in the hypoxic zone and organic matter transported into the region. Our results suggest that a combination of unique local hydrodynamic feature and decomposition of organic matter in water column and sediment are the cause of the formation and maintenance of the bottom hypoxia on the western shelf of the estuary during summer.

8063. 题目: The frequent effects of hydroxyl radicals on the oxidation of crude oil in soil
文章编号: N18081510
期刊: CLEAN - Soil, Air, Water
作者: Jinlan Xu, Qianqian Cao, Miaojia Zhang, Fan Wang, Tinglin Huang, Junhao Ren
更新时间: 2018-08-15
摘要: The characteristics of the hydroxyl radicals (•OH) frequently produced in the Fenton process and the effects of these radicals on the oxidation of hydrophobic total petroleum hydrocarbons (TPH) in soil were investigated. Twelve groups of Fenton oxidation experiments were conducted using two kinds of crude oil‐contaminated soil samples (S1 and S2) with different soil organic matter (SOM) contents. The results showed that the decrease of TPH increased by 6774 mg/kg (S1) and 5875 mg/kg (S2) by using the frequent •OH (•OHf). These results were two times the results obtained by using the single •OH (•OHs) (S1: 3410 mg/kg, S2: 2918 mg/kg). The decrease of hydrophobic long‐chain alkanes C21–C30 was greatly improved by using the •OHf, i.e., oxidation of 1557–3011 mg/kg in soil S1 and 1371–2532 mg/kg in soil S2. Moreover, the C21–C30 alkanes in soil S1 with low SOM (3.89%) were more degraded after oxidation. The residual non‐aqueous phase liquid (NAPL) TPH content by using the •OHf (266–1200 mg/kg) was much lower than that by using the •OHs (2519–4070 mg/kg). The residual of the NAPL TPH by using the •OHf was 11–29% of the residual by using the •OHs. This result indicated that residual NAPL TPH was reduced by using the •OHf, and the TPH contents in the two soil samples were efficiently oxidized.

8064. 题目: The changing faces of soil organic matter research
文章编号: N18081509
期刊: European Journal of Soil Science
作者: P. Smith, S. Lutfalla, W. J. Riley, M. S. Torn, M. W. I. Schmidt, J.-F. Soussana
更新时间: 2018-08-15
摘要: Summary For the 70th Anniversary of the establishment of the British Society of Soil Science, this short paper explores the idea that research on soil organic matter has remained a central theme within soil science over the past 70 years, albeit with changing emphasis and application. The number of publications on soil organic matter has increased greatly in recent decades; for example, there were almost 35 000 journal papers with this theme in the decade 2007–2016. Several topics in research on soil organic matter, such as soil fertility, have endured for a number of decades, with publications found on soil organic matter and fertility in the decade 1947–1956. A search with other keywords occurring with soil, such as climate change, biodiversity, fertility, quality, health and security, showed that several topics did not appear before the 1970s and 1980s, but since then the sub‐topics and applications have diversified. Carbon is a keyword that has become more associated with publications on soil organic matter; carbon is in over half of soil organic matter publications of the last decade. A closer examination of research on agricultural soil carbon sequestration since 1990 reveals that the focus of papers in the literature has changed over this period. A closer examination of papers on modelling shows that the next generation of soil organic matter models is developing from pseudo first‐order decay models using conceptual pools and prescribed controls of turnover time to vertically resolved, microbially explicit models representing mineral surface and plant interactions. Given its higher policy profile during the last 2 years, research on soil organic matter and soil carbon sequestration is predicted to have a bright future.

8065. 题目: Limited effect of organic matter on soil available water capacity
文章编号: N18081508
期刊: European Journal of Soil Science
作者: B. Minasny, A. B. McBratney
更新时间: 2018-08-15
摘要: Summary Soil water‐holding capacity is an important component of the water and energy balances of the terrestrial biosphere. It controls the rate of evapotranspiration, and is a key to crop production. It is widely accepted that the available water capacity in soil can be improved by increasing organic matter content. However, the increase in amount of water that is available to plants with an increase in organic matter is still uncertain and may be overestimated. To clarify this issue, we carried out a meta‐analysis from 60 published studies and analysed large databases (more than 50 000 measurements globally) to seek relations between organic carbon (OC) and water content at saturation, field capacity, wilting point and available water capacity. We show that the increase in organic carbon in soil has a small effect on soil water content. A 1% mass increase in soil OC (or 10 g C kg−1 soil mineral), on average, increases water content at saturation, field capacity, wilting point and available water capacity by: 2.95, 1.61, 0.17 and 1.16 mm H2O 100 mm soil−1, respectively. The increase is larger in sandy soils, followed by loams and is least in clays. Overall the increase in available water capacity is very small; 75% of the studies reported had values between 0.7 and 2 mm 100 mm−1 with an increase of 10 g C kg−1 soil. Compared with reported annual rates of carbon sequestration after the adoption of conservation agricultural systems, the effect on soil available water is negligible. Thus, arguments for sequestering carbon to increase water storage are questionable. Conversely, global warming may cause losses in soil carbon, but the effects on soil water storage and its consequent impact on hydrological cycling might be less than thought previously.

8066. 题目: Electrochemical advanced oxidation processes (EAOPs) as alternative treatment techniques for carwash wastewater reclamation
文章编号: N18081507
期刊: Chemosphere
作者: Soliu O. Ganiyu, Elisama Vieira dos Santos, Emily Cintia Tossi de Araújo Costa, Carlos A. Martínez-Huitle
更新时间: 2018-08-15
摘要: Electrochemical advanced oxidation processes such as electrooxidation (EO), electrooxidation with hydrogen peroxide generation (EO-H2O2) and electro-Fenton process (EF) have been investigated as alternative treatment techniques for complete removal of anionic surfactants and organic matters from real carwash wastewater. The electrochemical processes were performed with acidified real carwash wastewater using boron doped anode and carbon felt cathode. In all cases, the chemical oxygen demand (COD) removal efficiency was always increased with rise in applied current and complete organic matter decay was achieved at applied current of 500 mA or above after 6 h of electrolysis. Faster and higher COD decay was observed with EF compared to either EO or EO-H2O2 treatment, at all currents and electrolysis time. Besides, complete degradation of anionic surfactants – the major organic content of the wastewater could be achieved at all applied currents studied irrespective of the process used, indicating the efficacy of processes for total remediation of real carwash wastewater. The short-chain carboxylic acids formed as the final organic byproducts were identified and quantified by ion-exclusion chromatography. More so, lower energy consumption and higher current efficiency were achieved with EF compared to EO-H2O2. Electrochemical treatment was found to be a powerful technology for the complete abatement of organic matter in carwash wastewater for possible reuse.

8067. 题目: Stoichiometry of decomposing Spathodea campanulata leaves in novel puertorrican forests
文章编号: N18081506
期刊: Forest Ecology and Management
作者: Ariel E. Lugo, Oscar L. Abelleira Martínez
更新时间: 2018-08-15
摘要: One of the challenges in the restoration of degraded lands is the re-establishment of soil structure and fertility. Novel forests that regenerate on recently abandoned and degraded agricultural lands are among the first biotic systems that begin the process of soil rehabilitation. The rate of litter decomposition and associated element mobility is one of many processes that contribute to the understanding of how ecosystem-level processes restore eroded soils. We studied the stoichiometry of Spathodea campanulata leaves decomposing in novel subtropical moist forests. We found that the speed of leaf decomposition was high (annual decomposition constant of 5.0 to 2.6 or half-life of 51 to 98 days). Spathodea leaf mass loss was particularly fast during the first 16 days of decomposition (half-life of 33 days). Leaf litter was characterized by high chemical quality with low C/N, C/P, and N/P. During the leaf decomposition process, macroelements (N, P, K, Ca, and Mg) were more mobile than microelements (Al, Mn, Fe, and Na). As leaf litter decomposed, nitrogen increased in concentration, the quantity of all macroelements decreased, and microelements tended to increase in both concentration and quantity. Because of the rapid rate of decomposition and high chemical quality of Spathodea leaf litter, it appears that the potential for yielding residual soil organic matter from its leaves is reduced, but this is a tradeoff with the rapid release of elements, which contributes to the high juvenile tree density and primary productivity observed in novel Spathodea forests.

8068. 题目: Dominant Fraction of EPFRs from Nonsolvent-Extractable Organic Matter in Fine Particulates over Xi’an, China
文章编号: N18081505
期刊: Environmental Science & Technology
作者: Qingcai Chen, Haoyao Sun, Mamin Wang, Zhen Mu, Yuqin Wang, Yanguang Li, Yansong Wang, Lixin Zhang, Zimeng Zhang
更新时间: 2018-08-15
摘要: To understand the nature and possible sources of environmentally persistent free radicals (EPFRs) in atmospheric aerosols, the present study used a solvent extraction method to fractionate aerosol components with different polarities and solvent resistance in fine particulate matter (PM2.5) from Xi’an, China. The characteristics of EPFRs, that is., their concentration, type and lifetime, were obtained based on their electron paramagnetic resonance spectra. The results showed that the EPFRs in the PM2.5 samples were carbon-centered with a nearby heteroatom (g = 2.0031) and had a long half-life of more than 3 years. Nearly all of the extractable EPFRs were detected in the water-insoluble organic fraction and showed characteristics indicating that may contain oxygen-centered radical (g = 2.0038). Most of the total EPFRs in the PM2.5 were derived from solvent-resistant organic matter (88%), which likely consisted of graphene oxide analogues. The results suggest that previous studies may have missed the major proportion of EPFRs in atmospheric particulates if they only focused on solvent-extractable or metallic oxide-formed EPFRs. Our results showed that the EPFR concentration was significantly and positively correlated with the elemental carbon and NO2 concentrations, suggesting that traffic emissions may be an important source of EPFRs in PM2.5 over Xi’an.
图文摘要:

8069. 题目: Forest residue removal decreases soil quality and affects wood productivity even with high rates of fertilizer application
文章编号: N18081504
期刊: Forest Ecology and Management
作者: José Henrique Tertulino Rocha, José Leonardo de Moraes Gonçalves, Carolina Braga Brandani, Alexandre de Vicente Ferraz, Amanda Fernandes Franci, Eduardo Resende Girardi Marques, José Carlos Arthur Junior, Ayeska Hubner
更新时间: 2018-08-15
摘要: Forest residues are frequently used as energy sources by Brazilian forest companies. The removal of such residues is known to reduce wood productivity, especially when fertilizer application rate is low. This study aimed to evaluate after two forest rotations the effects of forest residue management on wood productivity when fertilizer is applied at a high rate; and the effect of timber harvest intensity on soil organic matter and microbial activity. We assessed tree growth, soil microbial biomass and activity, and we fractionated soil organic matter (SOM) via its oxidation resistance. These assessments were performed after conducting a field trial comparing harvest residue management over two successive rotations in the same plots. We found no significant effect of treatments on wood productivity when the residues were removed for the first time; however, wood productivity reduced by 15% during the second rotation with residue removal even with high rates of fertilizer application. Further, 40% reduction in microbial biomass and soil respiration was noted with forest residue removal. At the reestablishment time, the SOM in the top soil (0–0.05 m layer) was 25% lower at the site where the forest residues were removed, and this difference increased to 50% at 300 days after the reestablishment. This reduction was found mainly in the SOM labile fraction.
图文摘要:

8070. 题目: An experimental methodology to measure the reaction rate constants of processes sensitised by the triplet state of 4-carboxybenzophenone as a proxy of the triplet states of chromophoric dissolved organic matter, under steady-state irradiation conditions
文章编号: N18081503
期刊: Environmental Science: Processes Impacts
作者: Marco Minella, Lorenzo Rapa, Luca Carena, Marco Pazzi, Valter Maurino, Claudio Minero, Marcello Brigante, Davide Vione
更新时间: 2018-08-15
摘要: By a combination of transient absorption spectroscopy and steady-state irradiation experiments, we investigated the transformation of phenol and furfuryl alcohol (FFA) sensitised by irradiated 4-carboxybenzophenone (CBBP). The latter is a reasonable proxy molecule to assess the reactivity of the excited triplet states of the chromophoric dissolved organic matter that occurs in natural waters. The main reactive species for the transformation of both phenol and FFA was the CBBP triplet state, despite the fact that FFA is a commonly used probe for 1O2. In the case of FFA it was possible to develop a simple kinetic model that fitted well the experimental data obtained by steady-state irradiation, in a wide range of FFA concentration values. In the case of phenol the model was made much more complex by the likely occurrence of back reactions between radical species (e.g., phenoxyl and superoxide). This problem can be tackled by considering only the experimental data at low phenol concentration, where the degradation rate increases linearly with concentration. We do not recommend the use of 1O2 scavengers/quenchers such as sodium azide to elucidate CBBP photoreaction pathways, because the azide provides misleading results by also acting as a triplet-state quencher. Based on the experimental data, we propose a methodology for the measurement of the CBBP triplet-sensitisation rate constants from steady-state irradiation experiments, allowing for a better assessment of the triplet-sensitised degradation of emerging contaminants.
图文摘要:

8071. 题目: Inactivation of two Mycobacteria by free chlorine: Effectiveness, influencing factors, and mechanisms
文章编号: N18081502
期刊: Science of The Total Environment
作者: Jingyu Wang, Minghao Sui, Bojie Yuan, Hongwei Li, Hongtao Lu
更新时间: 2018-08-15
摘要: Chlorination is one of the most widely used disinfection techniques, and the problem of “chlorine-resistant bacteria” (CRB) has attracted more attention recently. In this study, the deactivation of typical CRB in water, Mycobacterium fortuitum (M. fortuitum) and Mycobacterium mucogenicum (M. mucogenicum), by free chlorine was investigated with Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) as the reference. The chlorination effectiveness of chlorine on M. fortuitum and M. mucogenicum and the effect of chlorine concentration, pH, and humic acid were studied. It was found that M. mucogenicum was more resistant to chlorine than M. fortuitum, both of which were much more resistant than E. coli and B. subtilis. The effect of disinfectant concentration on the inactivation efficiency was positive, whereas the influence of pH and humic acid was negative. The inactivation mechanisms were explored by analyzing the bacteria morphology, the destruction of cell membrane, the cell hydrophobicity, as well as total adenosine triphosphate (ATP), superoxide dismutase (SOD) activity. The slight destruction of the cell membrane was observed after deactivation with chlorine, and high hydrophobicity of the cell membrane combined with metabolic changes might lead to the chlorine tolerance of Mycobacteria.
图文摘要:

8072. 题目: Influence of ultrasound on the properties of dissolved organic matter with regards to proton and metal ion binding moieties
文章编号: N18081501
期刊: Water Research
作者: Hailong Liu, Guohao Chen, Lei Liu, Mingquan Yan
更新时间: 2018-08-15
摘要: Ultrasound is widely used in water and wastewater treatment. However, the influence of ultrasound on the composition and structure of dissolved organic matter (DOM) and consequently its behaviors is still unclear. In this study, the changes in proton and metal binding moieties in DOM caused by ultrasound at an environmentally relevant concentration (about 5 mg·L−1) were investigated using spectrophotometric titrations. The amounts of carboxylic and phenolic-like groups in DOM before and after ultrasound were quantified by the spectral parameter, Dslope350-400 (the differential slope of the Log-transformed DOM absorbance in the wavelength region of 350–400 nm) in combination with the non-ideal competitive adsorption (NICA) model. The results demonstrate that the concentration of carboxylic-like sites decreased with an increase in the ultrasound intensity at the same reaction time. However, the concentration of phenolic-like sites increased with an increase in the ultrasound intensity in most cases. The amounts of bound metal Ca(II) and Al(III) ions decreased with an increase of the ultrasound intensity due to the reduction of available total binding sites (carboxylic-like and phenolic-like groups) in the DOM after ultrasound. This study provides detailed in-situ information concerning the changes in the properties and behaviors of DOM in ultrasound, which would be useful to understand in more detail and to optimize the utility of ultrasound in water and wastewater treatment.
图文摘要:

8073. 题目: Increased current flow enhances the risk of organic carbon loss from Zostera marina sediments: Insights from a flume experiment
文章编号: N18081416
期刊: Limnology and Oceanography
作者: Martin Dahl, Eduardo Infantes, Rosanna Clevesjö, Hans W. Linderholm, Mats Björk, Martin Gullström
更新时间: 2018-08-14
摘要: Hydrodynamic processes are important for carbon storage dynamics in seagrass meadows, where periods of increased hydrodynamic activity could result in erosion and the loss of buried carbon. To estimate hydrodynamic impacts on the resuspension of organic carbon (Corg) in seagrass‐vegetated sediments, we exposed patches (0.35 × 0.35 cm) of Zostera marina (with different biomass, shoot densities, and sediment properties) to gradually increased unidirectional (current) flow velocities ranging from low (5 cm s−1) to high (26 cm s−1) in a hydraulic flume with a standardized water column height of 0.12 m. We found that higher flow velocities substantially increased (by more than threefold) the proportion of Corg in the suspended sediment resulting in a loss of up to 5.5% ± 1.7% (mean ± SE) Corg from the surface sediment. This was presumably due to increased surface erosion of larger, carbon‐rich detritus particles. Resuspension of Corg in the seagrass plots correlated with sediment properties (i.e., bulk density, porosity, and sedimentary Corg) and seagrass plant structure (i.e., belowground biomass). However, shoot density had no influence on Corg resuspension (comparing unvegetated sediments with sparse, moderate, and dense seagrass bed types), which could be due to the relatively low shoot density in the experimental setup (with a maximum of 253 shoots m−2) reflecting natural conditions of the Swedish west coast. The projected increase in the frequency and intensity of hydrodynamic forces due to climate change could thus negatively affect the function of seagrass meadows as natural carbon sinks.

8074. 题目: Interactions between algal (AOM) and natural organic matter (NOM): Impacts on their photodegradation in surface waters
文章编号: N18081415
期刊: Environmental Pollution
作者: Xiaofang Yang, Xing Zheng, Linjie Wu, Xin Cao, Yi Li, Junfeng Niu, Fangang Meng
更新时间: 2018-08-14
摘要: The occurrence of algae bloom would lead to the release of algae-derived organic matter (AOM) and then alter the abundance and behavior of dissolved organic matter (DOM) in aquatic ecosystems. In this study, the characteristics and photodegradation of AOM, naturally occurring organic matter (NOM) derived from soil and plants and their mixtures were explored to reveal the potential interactions between AOM and NOM in water. Results indicated that the protein-like components from AOM and the humic-like components from SRNOM took place inter-component interactions in the AOM-NOM mixtures. Meanwhile, application of two-dimensional Fourier transform infrared correlation spectroscopic (2D-FTIR-COS) analysis revealed that carboxylic C=O had a high priority to bind with other functional groups (e.g., phenolic-OH, polysaccharides C-O, amideⅡC-N/N-H and celluloses C-H). More crucially, it was found that the AOM-NOM mixtures subjected to a very different photodegradation behavior to their end-members (i.e., AOM and NOM), likely because of the occurrence of AOM-NOM interactions as well as their roles in mediating the yield of reactive oxygen species. For instance, the presence of AOM led to increased photodegradation degrees of the chromophoric fraction in NOM. In contrast, the NOM did not exhibit any photosensitization role in the photodegradation of the proteins from AOM. This study has potential implications for our understanding of the carbon cycling in anthropogenically impacted aquatic systems such as inland rivers and lakes.
图文摘要:

8075. 题目: Seasonal variability of CO2 emissions from sediments in planted mangroves (Northern Viet Nam)
文章编号: N18081414
期刊: Estuarine, Coastal and Shelf Science
作者: Ha Thi Hien, Cyril Marchand, Joanne Aimé, Nguyen Thi Kim Cuc
更新时间: 2018-08-14
摘要: Mangrove sediment stores a large quantity of organic carbon. However, its decomposition produces a significant amount of CO2, which can be further emitted to the atmosphere. The objective of the present study was to determine CO2 fluxes at the sediment-air interface of planted mangrove forests and adjacent bare sediment and determine how sediment characteristics, seasonal and tidal variations impact CO2 emissions. The results suggest sediment organic carbon content (TOC) was a key parameter influencing sediment properties beside others sediment characteristics such as grain-size and sediment water content. At the sediment-air interface, CO2 fluxes measured in the wet season were significantly higher (P < 0.001) than in dry season in mangroves, with mean values of 140.55 ± 109.66 and 50.50 ± 31.64 mmol CO2 m−2 d−1, respectively. In the bare sediment, the fluxes were significantly lower than in mangroves (P < 0.01), with 66.23 ± 38.16 mmol CO2 m−2 d−1 in the wet season and 18.61 ± 10.61 mmol CO2 m−2 d−1 in the dry season. The higher fluxes measured in the mangroves were associated with higher organic carbon content of the mangrove sediment. The study determined the CO2 emission rate in mangrove sediment was 1.75 ± 0.76 MgC ha−1 yr−1. After having removed 2 mm depth of sediment surface, containing microbes and biofilms, CO2 fluxes increased from 1.27 to 3.33 times compared to dark conditions. There was also evidence that temperature greatly influenced CO2 emissions with Q10 values of 2.63 for mangrove sediment and of 2.75 for bare sediment. This study suggests that TOC, temperature, tidal cycles and biofilms developing at the sediment surface were among the main factors driving CO2 emissions from the sediment of the planted mangroves. In a future research effort, it is recommended that CO2 fluxes are partitioned to identify CO2 origin, specifically the amount produced by root respiration. We also suggest that in mangrove planting programmes, a whole carbon budget be performed to determine the exact amount of carbon (or CO2eq) that can be fixed.

8076. 题目: Valorization of date palm (Phoenix dactylifera L.) pruning biomass by co-composting with urban and agri-food sludge
文章编号: N18081413
期刊: Journal of Environmental Management
作者: A. Vico, M.D. Pérez-Murcia, M.A. Bustamante, E. Agulló, F.C. Marhuenda-Egea, J.A. Sáez, C. Paredes, A. Pérez-Espinosa, R. Moral
更新时间: 2018-08-14
摘要: In the Mediterranean countries, there is an increasing production of date palm wastes (Phoenix dactylifera L.), not only due to the raising production of date palm fruits, but also derived from the maintenance of urban and peri-urban green areas, especially in those affected by red palm weevil (Rhynchophorus ferrugineus). The management of this increasing volume of green wastes usually concludes with a controlled disposal that implies an important loss of resources, in terms of organic matter, nutrients and energy. In addition, the rise of wastewater generation and the incentive of the wastewater treatment processes have derived in an increase of the amount of the sludge produced, which makes difficult its management. This work studies the feasibility of co-composting palm wastes with sludge from the urban and agri-food sectors as alternative treatment to manage these organic waste streams and to obtain added-value compost. For this, four mixtures (P1, P2, P3 and P4) were prepared using as main component palm leave waste (PL) mixed with different types of sludge. In the piles P1, P2 and P3, sewage sludge (SS) was used as co-composting agent, while agri-food sludge (AS) was used in P4. Throughout composting, the thermal profile of the composting piles was assessed, as were physical, chemical, physico-chemical and maturity parameters. In addition, the changes in water-soluble organic matter were assessed using chemical analytical methods and the excitation–emission matrix (EEM) fluorescence spectroscopy. The results obtained showed the viability of the co-composting process to obtain end-products with adequate maturity degree and physical characteristics for their potential use as substrates, except for the salt contents that can limit their use in some agricultural sectors.
图文摘要:

8077. 题目: Novel High-Flux Polyamide/TiO2 Composite Nanofiltration Membranes on Ceramic Hollow Fibre Substrates
文章编号: N18081412
期刊: Journal of Membrane Science
作者: Yu-Xuan Li, Yue Cao, Ming Wang, Zhen-Liang Xu, Hai-Zhen Zhang, Xi-Wang Liu, Ze Li
更新时间: 2018-08-14
摘要: Novel polyamide/TiO2 composite nanofiltration (NF) membranes were fabricated by interfacial polymerization of polyethyleneimine and trimesoyl chloride on TiO2-sol-modified ceramic hollow fibre microfiltration substrates. X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, and dynamic contact angle measurements were utilised to characterise the chemical structures and morphologies of the prepared membranes. The effects of monomer concentration, reaction time, and immersion time in the aqueous phase were thoroughly investigated in this study. The composite NF membrane prepared under optimised conditions exhibited a high pure water flux (PWF) of 105.5 L·m-2·h-1 and MgCl2 rejection of 95.5% at 4 bar. In addition, the membrane had excellent antifouling properties with high permeate recovery and low flux decline for bovine serum albumin and humic acid. During a 168 h long-run test, the membrane maintained a high PWF (>100.0 L·m-2·h-1) and high MgCl2 rejection (>95.0%).
图文摘要:

8078. 题目: Applying UV absorbance and fluorescence indices to estimate inactivation of bacteria and formation of bromate during ozonation of water and wastewater effluent
文章编号: N18081411
期刊: Water Research
作者: Ji Wu, Shi Cheng, Min-Hui Cai, Ya-Ping Wu, Yan Li, Ji-Chun Wu, Ai-Min Li, Wen-Tao Li
更新时间: 2018-08-14
摘要: Ozone is an effective oxidant and disinfectant commonly used for elimination of micropollutants and inactivation of resistant microbes. However, undesirable oxidation/disinfection byproducts such as bromate might form during ozonation. In this study, the UV absorbance and fluorescence indices were applied as surrogate indicators for predicting the inactivation of bacteria and formation of bromate during ozonation of water and wastewater effluents. The inactivation efficiencies of lab-cultured Escherichia coli (E. coli) and autochthonous bacteria were measured by plating (for E. coli only) and flow cytometry with fluorescence staining. During ozonation of E. coli spiked into wastewater effluents (∼106 cell/mL), the priority of inactivation efficiency determined by different cell viability methods were in the order of CFU > membrane damage > DNA damage. Approximately, 99% membrane damage and/or 90% DNA damage are conservatively supposed as an indicator for sufficient bacterial inactivation as well as degradation of antibiotic resistance genes. The related required O3 dosing thresholds for sufficient inactivation of E. coli and autochthonous bacteria refer to ∼0.6 O3/DOC (g/g), ∼50% decrease of UVA254, ∼60% decrease of UVA280, or ∼80% decrease of humic-like fluorescence. Within the range of 106–108 cell/mL, the bacterial concentration did not have significant effects on the required thresholds of the specific O3 doses or spectroscopic indicators required for bacterial inactivation. The addition of 50 mM tert-BuOH as ·OH scavenger increased the required specific ozone doses but decreased the losses of spectroscopic indicators necessary for sufficient bacterial inactivation, and also suggested that the membrane/DNA damages for bacterial inactivation were mainly attributed to the direct O3 attacks. The bromate concentration was determined using ion chromatography with MS/MS detection. The results showed that when O3 was dosed at the required thresholds for sufficient bacterial inactivation, bromate formation could usually be suppressed below 10 μg/L. The present work supports that it is possible to reach a balance between bacterial inactivation and bromate formation.
图文摘要:

8079. 题目: Priming effects of soil organic matter decomposition with addition of different carbon substrates
文章编号: N18081410
期刊: Journal of Soils and Sediments
作者: Zhiyuan Zhang, Wenfeng Wang, Jiaxin Qi, Huanyuan Zhang, Feng Tao, Renduo Zhang
更新时间: 2018-08-14
摘要: Purpose: The addition of organic substrates can change the decomposition rate of soil organic matter (SOM), which is termed as “priming effect.” The objective of this study was to explore the priming effects of SOM decomposition with the addition of different organic carbon substrates, including glucose, oxalic acid, and tannin. We hypothesized that with additions from labile to recalcitrant carbon substrates, the soil priming effects changed from positive to negative. Materials and methods: Representing from labile to recalcitrant carbon substrates, glucose, oxalic acid, and tannin were added to soil, respectively. Physicochemical properties of soil, carbon dioxide emission rate, soil organic carbon in the labile and recalcitrant carbon pools, microbial biomass carbon (MBC), and microbial community diversity and structure were measured in different treatments. Results and discussion: Results showed that the addition of glucose and tannin produced positive priming effects, while the addition of oxalic acid led to a negative priming effect. The addition of glucose and tannin significantly increased the MBC. The addition of glucose significantly promoted the carbon decomposition in both the labile and recalcitrant soil carbon pools. The addition of tannin greatly promoted carbon decomposition in the labile carbon pool and slightly decreased carbon decomposition in the recalcitrant carbon pool of the soil. However, the addition of oxalic acid reduced the MBC and resulted in insignificant changes of the different soil carbon pools. The addition of organic carbon substrates reduced the soil microbial community diversity, especially the addition of glucose. The different priming effects of the treatments with glucose and tannin were attributable to the different phases in the succession of SOM decomposition processes. The treatment with oxalic acid reduced the soil pH, resulting in inactive microbial growth and reproduction. Conclusions: The addition of both glucose (labile carbon) and tannin (recalcitrant carbon) produced positive priming effects. In contrast, the addition of oxalic acid produced a negative priming effect. Except the treatment with tannin, the hypothesis was successfully tested. The results from this study should be useful to better understand the turnover processes of soil carbon pools with exogenous carbon inputs.

8080. 题目: Lessons learnt from a pilot study on residual dye removal by an aerated treatment wetland
文章编号: N18081409
期刊: Science of The Total Environment
作者: F. Masi, A. Rizzo, R. Bresciani, N. Martinuzzi, S.D. Wallace, D. Van Oirschot, F. Macor, T. Rossini, R. Fornaroli, V. Mezzanotte
更新时间: 2018-08-14
摘要: Treatment wetlands (TWs) have shown good capacity in dye removal from textile wastewater. However, the high hydraulic retention times (HRTs) required by these solutions and the connected high area requirements, remain a big drawback towards the application of TWs for dye treatment at full scale. Aerated TWs are interesting intensified solutions that attempt to reduce the TW required area. Therefore, an aerated CW pilot plant, composed of a 20 m2 horizontal subsurface flow TW (HF) and a 21 m2 Free Water System (FWS), equipped with aeration pipelines, was built and monitored to investigate the potential reduction of required area for dye removal from the effluent wastewater of a centralized wastewater treatment plant (WWTP). During a 8 months long study, experimenting with different hydraulic retention times (HRTs – 1.2, 2.6 and 3.5 days) and aeration modes (intermittent and continuous), the pilot plant has shown a normal biological degradation for organic matter and nutrients, while the residual dye removal has been very low, as demonstrated by the absorbance measure at three wavelengths: at 426 nm (blue) the removal varies from −55% at influent absorbance of 0.010 to 41% at 0.060; at 558 nm (yellow) the removal is negative at 0.005 (−58%) and high at higher influent concentrations (72% at 0.035 of absorbance for the inlet); at 660 nm (red) −82% of removal efficiency was obtained at influent absorbance of 0.002 and 74% at 0.010. These results are a consequence of the biological oxidation processes taking place in the WWTP, so that the residual dye seems to be resistant to further aerobic degradation. Therefore, TWs enhanced by aeration can provide only a buffer effect on peak dye concentrations.
图文摘要:

 共 8958 条记录  本页 20 条  本页从 8061-8080 条  404/448页  首页 上一页  399 400 401 402 403 404 405 406 407 408 409  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。