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7581. 题目: Organic nitrogen addition suppresses fungal richness and alters community composition in temperate forest soils
文章编号: N18072128
期刊: Soil Biology and Biochemistry
作者: Lauren C. Cline, Julia A. Huggins, Sarah E. Hobbie, Peter G. Kennedy
更新时间: 2018-07-21
摘要: Human-driven increases in bioavailable nitrogen over the last century have revealed the critical need to understand how nitrogen availability influences terrestrial ecosystems. In contrast to widespread evidence that increasing inorganic nitrogen strongly influences the diversity and composition of plant and microbial communities, the effect of organic nitrogen addition, the predominant form of nitrogen in soils, remains less clear. In this study, we conducted a field experiment manipulating both the amount and composition of soil organic nitrogen present in soil fungal in-growth bags, followed by molecular characterization of fungal communities after a four-month incubation. Saprotrophic and ectomycorrhizal fungi readily colonized experimental in-growth bags, indicating a broad overlap in the fundamental niches of these two functional guilds. Increases in labile forms of organic nitrogen resulted in sharp declines in species richness and diversity across fungal guilds, as well as notable shifts in fungal community composition. The relative abundance of fungi classified as molds and yeasts peaked where organic nitrogen was both high and most labile, whereas slower-growing saprotrophic and ectomycorrhizal fungi were more abundant in the non-amended treatments. Taken together, our results indicate that similar to inorganic nitrogen, increasing the amount of organic nitrogen can dramatically alter the richness and composition of fungal communities in temperate forest soils.

7582. 题目: Novel insights into heavy metal pollution of farmland based on reactive heavy metals (RHMs): pollution characteristics, predictive models, and quantitative source apportionment
文章编号: N18072127
期刊: Journal of Hazardous Materials
作者: Lixun Zhang, Guangyu Zhu, Xin Ge, Gang Xu, Yuntao Guan
更新时间: 2018-07-21
摘要: Recently, soil contamination by heavy metals in farmland has become a severe problem. In this study, a novel assessment method of heavy metal pollution based on reactive heavy metals (RHMs) was introduced. RHMs showed strong correlation with soil profile and land use, distinctly different from the variation of total heavy metals. According to modified geoaccumulation and Hakanson index, farmlands in study area were certainly polluted by various heavy metals, but had low ecological risk. RHMs were greatly influenced by soil properties such as nitrogen, phosphorus, organic matter (OM), pH, moisture content, cation exchange capacity (CEC), electrical conductivity, inorganic anion, and soil texture. Freundlich-type empirical models were developed by combining pH, OM, CEC, total phosphorus, and clay for sufficiently robust and accurate prediction of RHM contents in farmland. The absolute principal component score with multiple linear regression (APCS-MLR) model was used to quantify sources of RHMs in farmland. Agricultural production (water-fertilizer management practice and fertilizer/pesticide use) was the major influence on RHMs with contributions greater than 50% for Fe, Cu, Zn, Pb, and As. Industrial activity, traffic emission, and soil erosion should be also given special attentions because of their great influence on soil RHM contents.
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7583. 题目: Intensity and frequency of nitrogen addition alter soil chemical properties depending on mowing management in a temperate steppe
文章编号: N18072126
期刊: Journal of Environmental Management
作者: Ruzhen Wang, Yunhai Zhang, Peng He, Jinfei Yin, Junjie Yang, Heyong Liu, Jiangping Cai, Zhan Shi, Xue Feng, Feike A. Dijkstra, Xingguo Han, Yong Jiang
更新时间: 2018-07-21
摘要: Anthropogenic nitrogen (N) enrichment can significantly alter soil chemical properties in various ecosystems. Previous manipulative N experiments mainly focused on the intensity of N addition on soil properties by changing N input rates. It remains unclear, however, whether frequency of N addition can affect soil chemical properties. We examined the effects of frequency (2 versus 12 applications yr-1) and rate (ranging from 0 to 50 g N m-2 yr-1) of N addition on soil chemical properties of pH, base cations, soil pH buffering capacity (pHBC), and soil available micronutrients in a temperate steppe with and without mowing. Mowing significantly increased the effective cation exchange capacity (ECEC), soil exchangeable Ca and Na, available Fe, and soil pHBC when N was applied at low frequency. Low frequency of N addition significantly decreased soil pH and exchangeable Na but increased soil exchangeable Mg without mowing; however, it increased soil exchangeable Na and available Zn with mowing, while available Fe and Mn increased both with and without mowing. Higher rates of N addition (≥20 g N m-2 yr-1) decreased soil pH, ECEC and exchangeable Ca but increased soil available Fe, Mn and Cu regardless of the mowing treatment and frequency of N addition. Changes in soil organic matter, pHBC and ECEC were the main reasons affecting soil pH across mowing and N application treatments. Our results indicate that frequency of N addition played an essential role in altering soil chemical properties. Simulating N deposition via large and infrequent N additions can underestimate (exchangeable Mg and available Fe and Mn) or overestimate (soil pH and exchangeable Na) changes in soil properties. Our results further suggest that the effects of frequency of N addition on soil chemical attributes in semi-arid grassland ecosystems can be regulated by appropriate mowing management.
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7584. 题目: Influence of chain length of long-chain fatty acid surfactant on the thermal conductivity of magnetite nanofluids in a magnetic field
文章编号: N18072125
期刊: Colloids and Surfaces A: Physicochemical and Engineering Aspects
作者: Arun Dadwal, P.A. Joy
更新时间: 2018-07-21
摘要: Stable magnetic nanofluids are prepared by dispersing long-chain fatty acid surfactants coated magnetite (Fe3O4) nanoparticles in toluene and investigated the effect of chain length of the surfactant molecules on the thermal conductivity of the magnetite nanofluids in a magnetic field. Superparamagnetic magnetite nanoparticles having a comparable particle size (~10 nm) are coated with three different long-chain fatty acid surfactants; myristic acid (C13H27COOH), palmitic acid (C15H31COOH) and stearic acid (C17H35COOH). The thermal conductivity of the nanofluids, in a magnetic field, is found to decrease with increasing the chain length of the surfactant molecule. Among the three fluids, the shorter chain myristic acid coated nanofluid showed larger enhancement in the thermal conductivity at smaller fields as compared to the other fluids. The results indicated that the chain length of the surfactant molecule present on the surface of the magnetite nanoparticles affect the thermal conductivity of the magnetic nanofluid in an external magnetic field, due to the difference in the extent of interdigitation of the surfactant molecules.
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7585. 题目: Fabrication of GO modified PVDF membrane for dissolved organic matter removal: removal mechanism and antifouling property
文章编号: N18072124
期刊: Separation and Purification Technology
作者: Jingjing Zhao, Yu Yang, Chen Li, Li-an Hou
更新时间: 2018-07-21
摘要: In this study, graphene oxide (GO) layers were successfully grafted onto a polyvinylidene fluoride (PVDF) membrane using chemical activated treatment and layer-by-layer assembly method. The physicochemical properties of GO modified membranes were analyzed by Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, zeta potential, and water contact angle measurements. Our results showed that GO layers resulted in a decrease in pore size, an increase in the negative surface charge and hydrophilicity of the modified membrane. Thus, much higher removal rates of proteins, humic acids and fulvic acids were observed for GO modified membranes due to the enhanced size exclusion. Notably, the higher rejection of the smaller molecular weight (MW) organics in the range of 50-500 Da was also obtained for the GO modified membrane, which was attributed to the size exclusion of GO layers’ surface and adsorption effect of GO layers. The foulant desorbed from fouled membrane before and after physical rinsing illustrated that, the hydrophilic and proteins with large MW were the major foulants resulting in irreversible fouling for both pristine and GO modified membranes. The pristine membrane exhibited severe irreversible fouling caused by pore blocking. However, GO modified membrane displayed the efficient antifouling performance. The foulants were more prone to forming a loose cake layer on the surface and prevented membrane pore blocking due to the negative charge and stronger hydrophilicity of GO layers, which resulted in a lower irreversible fouling ratio during the filtration of DOM solution. Therefore, GO modified membranes exhibited the higher rejections of foulants with large MW and small MW and better antifouling property in comparison of pristine membrane.

7586. 题目: Changes in the distribution of Uvigerinidae species over the past 775?kyr: Implications for the paleoceanographic evolution of the Japan Sea
文章编号: N18072123
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Manisha Das, Raj K. Singh, Nishant Vats, Ann Holbourn, S. Mishra, S.H. Farooq, D.K. Pandey
更新时间: 2018-07-21
摘要: The distribution of benthic foraminifera of the Uvigerinidae family, which are abundant in middle to upper Pleistocene samples from the Yamoto Basin in the Japan Sea, have been analyzed quantitatively and used for paleoceanographic interpretations. Twenty-three Uvigerinidae species are reported from IODP Site U1426, 6 of which are present in at least three or more samples with 10% or more abundance and considered as dominant species. The abundance and ecological preferences of dominant Uvigerinidae species, comprised of Uvigerina mediterranea, Uvigerina yabei, Uvigerina sp.1, Uvigerina peregrina suggest dysoxic conditions, with high influx of organic matter between 775 and 475 ka in response to the enhanced flow of the Tsushima Warm Current. The end of MIS 13 marked the onset of more extreme glacial interglacial climate cycles in the Japan Sea. Glacial interglacial alternations of Uvigerina peregrina and Trifarina angulosa from 475 ka to the Holocene indicate major fluctuations in circulation and productivity within this semi-enclosed basin. Both U. peregrina and T. angulosa respond to 100 kyr variability, reflecting the paleoclimatic shift and global ice volume changes associated with the Middle Pleistocene Transition.

7587. 题目: Effect of bioflocculants on the coagulation activity of alum for removal of trihalomethane precursors from low turbid water
文章编号: N18072122
期刊: Journal of Environmental Sciences
作者: Tanwi Priya, Abhrajyoti Tarafdar, Bramha Gupta, Brijesh Kumar Mishra
更新时间: 2018-07-21
摘要: Reactivity of chlorine towards hydrophobic groups present in natural organic matter (NOM) provokes the formation of carcinogenic disinfection byproducts such as trihalomethanes in chlorinated water. The present study aimed to investigate the variations in coagulant activity of alum using two different bioflocculants (coagulant aid) namely, Moringa oleifera and Cyamopsistetragonoloba for the removal of hydrophobic fractions of NOM and subsequent chlorine consumption by treated water. Effect of dual coagulants on trihalomethane surrogate parameters such as total organic carbon, dissolved organic carbon, UV absorbing materials and prominent hydrophobic species such as phenolic groups along with aromatic chromophores, polyhydroxy aromatic moiety have also been studied. The concept of differential spectroscopy and absorbance slope index has been employed to understand the combined effects of alum-bioflocculants on the reactivity of NOM with chlorine. Our result shows that the combination of alum and C. tetragonoloba is more efficient for reducing trihalomethane surrogates from chlorinated water as compared to M. oleifera. C. tetragonoloba elicited synchronized effects of sweep coagulation and particle bridging-adsorption which eventually facilitated efficient removal of hydrophobic fractions of NOM. The variation in the mechanistic approach of bioflocculants was due to the presence of cationic charge on M. oleifera and adhesive property of C. tetragonoloba.
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7588. 题目: Relating Cd2 + binding by humic acids to molecular weight: A modeling and spectroscopic study
文章编号: N18072121
期刊: Journal of Environmental Sciences
作者: Hongcheng Bai, Zhenmao Jiang, Minjin He, Biying Ye, Shiqiang Wei
更新时间: 2018-07-21
摘要: Molecular weight (Mw) is a fundamental property of humic acids (HAs), which considerably affect the mobility and speciation of heavy metals in the environment. In this study, soil humic acid (HA) extracted from Jinyun Mountain, Chongqing was ultra-filtered into four fractions according to the molecular weight, and their properties were characterized. Complexation of cadmium was investigated by titration experiments. For the first time, Langmuir and non-ideal competitive adsorption-Donna (NICA-Donnan) models combined with fluorescence excitation-emission matrix (EEM) quenching were employed to elucidate the binding characteristics of individual Mw fractions of HA. The results showed that the concentration of acidic functional groups decreased with increasing Mw, especially the phenolic groups. The humification degree and aliphaticity increased with increasing Mw as indicated by elemental composition analysis and FT-IR spectra. The binding capacity of Cd2 + to Mw fractions of HA followed the order UF1 (< 5 kDa) > UF2 (5–10 kDa) > UF4 (> 30 kDa) > UF3 (10–30 kDa). Moreover, the distribution of cadmium speciation indicated that the phenolic groups were responsible for the variations in binding of Cd2 + among different Mw fractions. The results of fluorescence quenching illustrated that the binding capacity of Cd2 + to Mw fractions was controlled by the content of functional groups, while the binding affinity was largely influenced by structural factors. The results provide a better understanding of the roles that different HA Mw fractions play in heavy metal binding, which has important implications in the control of heavy metal migration and bio-toxicity.
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7589. 题目: Spectroscopic study on transformations of dissolved organic matter in coal-to-liquids wastewater under integrated chemical oxidation and biological treatment process
文章编号: N18072120
期刊: Journal of Environmental Sciences
作者: Siwei Peng, Xuwen He, Hongwei Pan
更新时间: 2018-07-21
摘要: A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes, which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter (BAF) treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols; benzene, toluene, ethylbenzene, and xylene (BTEX); aromatic hydrocarbons; aliphatic acids; aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF process. Biodegradable organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis (EEM-PARAFAC). Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.
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7590. 题目: Influence of sodium dodecyl sulfate coating on adsorption of methylene blue by biochar from aqueous solution
文章编号: N18072119
期刊: Journal of Environmental Sciences
作者: Wei Que, Luhua Jiang, Chen Wang, Yunguo Liu, Zhiwei Zeng, Xiaohua Wang, Qimeng Ning, Shaoheng Liu, Peng Zhang, Shaobo Liu
更新时间: 2018-07-21
摘要: Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, environmental chemicals such as surfactants will load onto the released biochar and change its physicochemical characteristics and adsorption behavior toward pollutants. In this study, sodium dodecyl sulfate (SDS), as one type of anionic surfactant, was coated onto biochar with different loading amounts. The influence of SDS loading onto biochar's physicochemical properties were investigated by Fourier transform infrared (FT-IR) spectroscopy, elemental analysis, zeta potential and Brunauer–Emmett–Teller (BET) surface area and pore size distribution analysis. Results showed that the pore size of the biochar decreased gradually with the increase of SDS loading because of the surface-adsorption and pore-blocking processes; the pH of the point of zero charge (pHPZC) decreased with increasing SDS loading. Although surface-coating with SDS decreased the pore size of the biochar, its adsorption capacity toward Methylene Blue (MB) significantly increased. The biochar-bound SDS introduced functional groups and negative charges to the biochar surface, which could thus enhance the adsorption of MB via hydrogen bonding and electrostatic interaction. The results can shed light on the underlying mechanism of the influence of anionic surfactants on the adsorption of MB by biochar.
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7591. 题目: Sediment granulometry and salinity drive spatial and seasonal variability of an estuarine demersal fish assemblage dominated by juvenile fish
文章编号: N18072118
期刊: Estuarine, Coastal and Shelf Science
作者: Yureidy Cabrera Páez, Consuelo María Aguilar-Betancourt, Gaspar González-Sansón, Fátima Negrete Rodríguez, Michelle Gray
更新时间: 2018-07-21
摘要: Abiotic factors are known to structure estuarine fish communities; however, their effects on the ichthyofauna are not yet clear. The objective of this study was to evaluate abundance and composition, by species and size, of the demersal ichthyofauna in a Mexican Central Pacific lagoon, and correlate its spatial and seasonal variations with selected abiotic factors. Eight sampling campaigns were conducted in representative months of the dry and rainy seasons between April 2015 and February 2017. Salinity, temperature and sediment granulometry were recorded. A total of 10 093 individuals of 64 species were collected and measured for total length. Of the 22 most abundant species, 19 were mainly juveniles (>50%). Diapterus brevirostris, Achirus mazatlanus, Centropomus robalito and Lutjanus argentiventris comprised more than 80% of the total collection. PERMANOVA yielded significant differences in fish community composition between sites and months, and post hoc tests resulted in four homogenous, significantly different groups of sites based on fish assemblage composition. These groups of sites lie well ordered along a west-east axis inside the lagoon. Two well separated seasonal groups of months were defined, namely dry season (February, April) and rainy season (July, October). The spatial changes in abundance and composition of the fish fauna were primarily explained by the Site factor in a spatial scale, while the Month factor influenced to a lesser degree the community structure on a seasonal scale. Redundancy analysis showed the type of sediment, the bottom salinity and the organic matter content were highly correlated with the composition and abundance of ichthyofauna in the lagoon. One species group (dominated by D. brevirostris, C. robalito and A. mazatlanus) was found to be highly positively correlated with percentage of mud and organic matter but negatively correlated with bottom salinity. Another species group (dominated by Diodon holocanthus, Eucinostomus dowii, Sphoeroides annulatus and Chaetodon humeralis) was highly correlated with percentage of sand and bottom salinity. A high number of juveniles in the catches also validates the Barra de Navidad lagoon as a probable nursery area.

7592. 题目: Optical properties of straw-derived dissolved organic matter and growth inhibition of Microcystis aeruginosa by straw-derived dissolved organic matter via photo-generated hydrogen peroxide
文章编号: N18072117
期刊: Environmental Pollution
作者: Hua Ma, Liping Huang, Jie Zhang, Dezhi Shi, Jixiang Yang
更新时间: 2018-07-21
摘要: Recent advances in research on algae inhibition by using low-cost straw proposed a possible mechanism that reactive oxygen species (ROS) generated by the solar irradiation of straw-derived dissolved organic matter (DOM) might contribute to cyanobacteria inhibition. However, this process is not clearly understood. Here, DOM from three types of straw (barley, rice, and wheat) and natural organic matter (NOM) isolates were investigated in terms of their photochemical properties and ROS generating abilities. Results demonstrated that the DOM derived from the aeration decomposition of barley straw (A-DOMbs) yielded the best formation efficiencies of hydrogen peroxide (H2O2) and hydroxyl radicals ( OH) under solar-simulated irradiation in all organic matter samples. Correlation analysis implies that optical parameters and phenolic hydroxyl group contents can signify ROS generating abilities of different DOM solutions. Bioassay results show that A-DOMbs possesses the highest inhibition performance for M. aeruginosa in all DOM samples, much higher than those of NOM isolates. The addition of catalase greatly relieves the inhibition performance, making the loss of chlorophyll a content decreased from 37.14% to 7.83% in 2 h for A-DOMbs, which implies that for cyanobacteria growth inhibition, photochemically-produced H2O2 from SOM is far more important than singlet oxygen (1O2),· OH, and even SOM itself. Our results show that H2O2 photochemically generated from straw-derived DOM is able to result in rapid inhibition of M. aeruginosa in a relatively short period, furthering the understanding of complicated mechanisms of cyanobacteria inhibition by using low-cost straw in eutrophic waters.
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7593. 题目: Unraveling microbial turnover and non-extractable residues of bromoxynil in soil microcosms with 13C-isotope probing
文章编号: N18072116
期刊: Environmental Pollution
作者: Karolina M. Nowak, Markus Telscher, Erika Seidel, Anja Miltner
更新时间: 2018-07-21
摘要: Bromoxynil is a widely used nitrile herbicide applied to maize and other cereals in many countries. To date, still little is known about bromoxynil turnover and the structural identity of bromoxynil non-extractable residues (NER) which are reported to occur in high amounts. Therefore, we investigated the microbial turnover of 13C-labeled bromoxynil for 32 days. A focus was laid on the estimation of biogenic NER based on the turnover of 13C into amino acids (AA). At the end, 25% of 13C6-bromoxynil equivalents were mineralized, 2% assigned to extractable residues and 72.5% to NER. Based on 12% in the 13C-total AA and an assumed share of AA of 50% in microbial biomass we arrived at 24% of total 13C-biogenic NER. About 33% of the total 13C-NER could thus be explained by 13C-biogenic NER; 67% was unknown and by definition xenobiotic NER with potential for toxicity. The 13C label from 13C6-bromoxynil was mainly detected in the humic acids (28.5%), but significant amounts were also found in non-humics (17.6%), fulvic acids (13.2%) and humins (12.7%). The 13C-total amino acids hydrolyzed from humic acids, humins and fulvic acids amounted to 5.2%, 6.1% and 1.2% of 13C6-bromoxynil equivalents, respectively, corresponding to total 13C-biogenic NER amounts of 10.4%, 12.2% and 2.4%. The humins contained mostly 13C-biogenic NER, whereas the humic and fulvic acids may be dominated by the xenobiotic NER. Due to the high proportion of unknown 13C-NER and particularly in the humic and fulvic acids, future studies should focus on the detailed characterization of these fractions.
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7594. 题目: Comparison of organic matter removals in single-component and bi-component systems using enhanced coagulation and magnetic ion exchange (MIEX) adsorption
文章编号: N18072115
期刊: Chemosphere
作者: Yingying Chen, Weiying Xu, Hongjian Zhu, Dong Wei, Ning Wang, Mengting Li
更新时间: 2018-07-21
摘要: Natural organic matter (NOM) in aquatic environments have a significant impact on NOM-organic compound interactions, which could strongly affect the distribution and transformation of organic compounds during water treatment. This study focused on the removals of NOM (humic acid, HA) and synthetic organic matter (ibuprofen, IBP) through enhanced coagulation and magnetic ion exchange (MIEX) resin adsorption in single and bi-component systems. Two coagulants, traditional aluminum sulfate (AS) and lab-prepared polyaluminum chloride (PACl), were employed. The charge properties, particle size distribution, and fractal dimension (Df) during organic matter removal were studied in both the single and bi-component systems to explore the purification behaviors and mechanistic effects of interactions between coagulants, MIEX, and organic matters. The experimental results indicated that the Al-based coagulants could remove over 80% of HA in both the single and IBP-HA combined systems, while the presence of HA could considerably improve the IBP removal rate. The aggregates formed during single-component coagulation were larger, but weaker and more loosely structured than those formed in the bi-component system under the same coagulation conditions. In the single-component system, the maximum removal efficiencies of IBP and HA by MIEX adsorption were 65% and 72%, respectively, at a resin dosage of 20.0 mL/L and mixing time of 60 min. Under the same conditions, the removals of these components in the bi-component system were improved to 68% and 98%, respectively. The reaction rate between IBP and MIEX resin was found faster than that between HA and MIEX resin.
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7595. 题目: The role of the anode material and water matrix in the electrochemical oxidation of norfloxacin
文章编号: N18072114
期刊: Chemosphere
作者: Salatiel W. da Silva, Emma M.O. Navarro, Marco A.S. Rodrigues, Andréa M. Bernardes, Valentín Pérez-Herranz
更新时间: 2018-07-21
摘要: The roles of the anode material, boron-doped diamond (BDD), with different boron (B) and substrate Silicon (Si) or Niobium (Nb) content, and one dimensionally stable anode (DSA ), were evaluated in the oxidation of norfloxacin (NOR) by electrochemical advanced oxidation process (EAOP). The effect of other components in real wastewater on the performance of EAOP was also studied. The anode materials were characterized by cyclic voltammetry, regarding diamond quality, electro-generation of oxidants and NOR oxidation mechanism (direct and/or indirect). The results showed that the anode material influences on the NOR oxidation pathway, due to distinct characteristics of the substrate and the coating. Apparently, low difference in diamond-sp /sp2-carbon ratio (Si/BDD100 × Si/BDD2500) does not leads to significant differences in the EAOP. On the other hand, the variation in the sp /sp2 ratio seems to be higher when Si/BDD2500 and Nb/BDD2500 are compared, which would explain the best current efficiency result for Si substrate. However, the Nb substrate presented a similar current efficiency and a 60% lower energy consumption. Dissolved organic matter (DOM) present in the real wastewater affect the EAOP-Nb/BDD due to HO and persulfate ions scavenged. However, when supporting electrolyte was added to a real wastewater spiked with NOR, the NOR decay reaches similar values found to the synthetic one. Due to the energy saving and mechanical properties, Nb substrate presents some technological advantages in relation to Si, which can facilitate the application to industrial levels.

7596. 题目: Chromium uptake by lettuce as affected by the application of organic matter and Cr(VI)-irrigation water: Implications to the land use and water management
文章编号: N18072113
期刊: Chemosphere
作者: Stavros Raptis, Dionisios Gasparatos, Maria Economou-Eliopoulos, Anastasios Petridis
更新时间: 2018-07-21
摘要: Toxic chromium [(Cr(VI)] in food chain has created an alarming situation for human life and ecosystems. The present study through a greenhouse pot experiment aims to (a) investigate the ability of organic matter in reducing Cr uptake by lettuce (Lactuca sativa L.) from a sandy loam soil irrigating with Cr(VI)-water, (b) to provide a way for the restriction of Cr transfer from contaminated soils and irrigation water to plants/crops and (c) to contribute to the better management of soil (land) and water use, without reduction of the agricultural production. Since soil and groundwater contamination by Cr is a potential risk in a worldwide scale, due to industrial activities and/or natural processes, organic carbon may play a key role in the mobility of added Cr(VI) to soil via irrigation water, in a significant way. The cultivation of lettuce, using organic matter in the form of leonardite (10 and 30 wt%) and Cr(VI)-irrigation water (100, 200 and 300 mgL 1), showed that the uptake of Cr in both shoots and roots increased with increasing concentration of Cr in the irrigation water. The highest Cr values in shoots (average = 10 mg/kg) and in roots (average = 28 mg/kg) were recorded in those plants cultivated in soil after the addition of Cr(VI)- water without organic matter, whereas the lowest Cr values in shoots (average = 0.44 mg/kg) and in roots (average = 0.7 mg/kg) were recorded in those plants cultivated in soil with addition of 30 wt% organic matter. The used leonardite as organic matter that is an oxidized form of lignite, due to its high content of humic acid is considered to be a useful organic fertilizer that provides possibilities for combining food production with soil protection. Therefore, the application of the natural organic material leonardite, as a land management technique, seems to be a cost-effective method consistent to related protocols for the protection of the soil quality.
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7597. 题目: Screening of biological sulfate reduction conditions for sulfidogenesis promotion using a methanogenic granular sludge
文章编号: N18072112
期刊: Chemosphere
作者: M. Mora, J. Lafuente, D. Gabriel
更新时间: 2018-07-21
摘要: Effluents containing great amounts of oxidized sulfur compounds, such as sulfate or sulfite, can be valorized as elemental sulfur from a sequential reduction-oxidation biological process. However, the most important, challenging step to be optimized is the reduction of sulfate. The present study aimed at seeking out the optimal conditions to promote sulfidogenesis instead of methanogenesis using waste carbon sources and a methanogenic granular sludge. Crude glycerol showed better results in terms of the consumed COD/S-Sulfate ratio compared with acetate, cheese whey, pig slurry, and vinasse. Then, the screening of several conditions (T, pH, and COD/S-Sulfate ratio) and the effects of air presence and dissolved sulfide inhibition on sulfate reduction was carried out. Sulfidogenesis was promoted at 35 °C, pH = 8.5, COD/S-Sulfate ratio above 7.0 g O2 g-1 S, microaerophilic conditions, and dissolved sulfide concentrations below 250 mg S2 L-1. These conditions were tested for nearly 3 months in the startup and operation of a 2 L UASB reactor. An inlet sulfate concentration of 220 mg S L-1 and an HRT of 2 h were set. Removal efficiencies of approximately 90% were obtained with less than 20% of organic matter destined for biogas production.

7598. 题目: What is driving the NF-κB response in environmental water extracts?
文章编号: N18072111
期刊: Chemosphere
作者: Peta A. Neale, Frederic D.L. Leusch, Beate I. Escher
更新时间: 2018-07-21
摘要: In vitro bioassays are increasingly applied for water quality monitoring, with assays indicative of adaptive stress responses commonly included in test batteries. The NF-κB assay is responsive to surface water and wastewater extracts, but the causative compounds are unknown and micropollutants typically found in water do not activate the NF-κB assay. The current study aimed to investigate if co-extracted organic matter and/or endotoxins could cause the NF-κB response in surface water extracts. The effect of model bacterial lipopolysaccharides (LPS) and dissolved organic carbon (DOC) was evaluated in the NF-κB assay both before and after solid-phase extraction (SPE), with 7% effect recovery for LPS and between 7 and 52% effect recovery for DOC observed. The NF-κB response, endotoxin activity, micropollutant concentration and total organic carbon concentration was measured in four surface water extracts. All water extracts showed a response in the NF-κB assay, but the detected micropollutants could not explain the effect. Comparison of predicted bioanalytical equivalent concentrations based on micropollutant, DOC and endotoxin concentrations in surface water with experimental bioanalytical equivalent concentrations suggest that co-extracted endotoxins are the most important drivers of the observed effect, with DOC only having a minor contribution. While in vitro bioassays typically detect mixtures of organic micropollutants, the current study shows that the NF-κB assay can integrate the effects of co-extracted endotoxins. Given that endotoxins can pose a risk for human health, the NF-κB assay is a valuable inclusion in bioanalytical test batteries used for water quality monitoring.
图文摘要:

7599. 题目: Influence of electrode placement for mobilising and removing metals during electrodialytic remediation of metals from shooting range soil
文章编号: N18072110
期刊: Chemosphere
作者: Kristine B. Pedersen, Pernille E. Jensen, Lisbeth M. Ottosen, John Barlindhaug
更新时间: 2018-07-21
摘要: Electrodialytic remediation was applied to a shooting range soil to investigate the influence of electrode placement on the removal and binding of metals during the treatment. The set-up was based on a 2-compartment cell, in which the cathode was separated from the soil by a cation exchange membrane and the anode was placed directly in the soil, thereby introducing protons and oxygen directly in the soil. Mobilisation of metals from less available fractions (oxidisable and residual) in the soil occurred, due to oxidation/dissolution of insoluble/soluble organic matter and possibly metal oxides in the residual fraction. The transport via electromigration out of the soil and/or re-precipitation in other fractions of the soil (oxidisable, reducible, exchangeable) depended on the metal. More than 30% of the initial content of Mn, Cd, Cu, Pb and Zn and less than 20% of the initial content of Al, Fe, K, Mg, As, Cr and Ni was transported out of the soil. By decreasing the distance between the electrodes from 3.0 to 1.5 cm, the removal of the targeted metal for remediation, Pb, was improved by more than 200%, from 14 to 31%. A similar removal could be achieved in experiments with long distance between electrodes (3.0 cm) by increasing the current intensity from 4 to 10 mA and/or the remediation time from 7 to 35 d. The experiments showed that the design and optimisation of electrodialytic remediation depends on the targeted metal and metal partitioning.

7600. 题目: Amendment of soil by biochars and activated carbons to reduce chlordecone bioavailability in piglets
文章编号: N18072109
期刊: Chemosphere
作者: M. Delannoy, S. Yehya, D. Techer, A. Razafitianamaharavo, A. Richard, G. Caria, M. Baroudi, E. Montargès-Pelletier, G. Rychen, C. Feidt
更新时间: 2018-07-21
摘要: Chlordecone (Kepone or CLD) is a highly persistent pesticide formerly used in French West Indies. Nowadays high levels of this pesticide are still found in soils which represent a subsequent source of contamination for outdoor-reared animals. In that context, sequestering matrices like biochars or activated carbons (ACs) are believed to efficiently decrease the bioavailability of such compounds when added to contaminated soils. The present study intends to test the respective efficiency of soil amendment strategies using commercial ACs or biochars (obtained by a 500 °C or 700 °C pyrolysis of 4 distinct type of wood). This study involved three experimental steps. The first one characterized specific surface areas of biochars and ACs. The second one assessed CLD-availability of contaminated artificial soils (50 μg g-1 of Dry Matter) amended with 5% of biochar or AC (mass basis). The third one assessed CLD bioavailability of those artificial soils through an in vivo assay. To limit ethically the number of animals, selections of the most promising media were performed between each experimental steps. Forty four castrated male 40-day-old piglets were exposed during 10 day by amended artificial soils according to their group (n = 4). Only treatment groups exposed through amended soil with AC presented a significant decrease of concentrations of CLD in liver and adipose tissue in comparison with the control group (p < 0.001). A non-significant decrease was obtained by amending artificial soil with biochars. This decrease was particularly high for a coconut shell activated carbon were relative bioavailability was found lower than 3.2% for both tissues. This study leads to conclude that AC introduced in CLD contaminated soil should strongly reduce CLD bioavailability.

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