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8141. 题目: Identification of a novel C33 botryococcane and C33 botryococcanone in the Maoming Basin, China
文章编号: N18080817
期刊: Organic Geochemistry
作者: Jing Liao, Hong Lu, Qiao Feng, Youping Zhou, Quan Shi, Ping'an Peng, Guoying Sheng
更新时间: 2018-08-08
摘要: A novel C33 botryococcane in a sedimentary sample from the Maoming Basin in China was found to have a methyl group positioned β to the quaternary carbon C-10 in its structure based on IR, MS and NMR analyses and Lindeman-Adams modelling. This structure is inconsistent with the prediction from the currently accepted botryococcene biosynthetic pathway and different from the skeleton for the C33 botryococcanes suggested in the literature. A C33 botryococcan-24-one with the same carbon skeleton as the C33 botryococcane was also found to co-occur in the sediment sample. The location of the carbonyl group at C-24 is different from that of a previously reported botryococcenone from an Australian collection of race B of Botryococcus braunii where it is positioned at C-15. We propose a biogeochemical pathway to explain the occurrence of this unique skeleton in the Maoming Basin sediment. The biochemical component of the pathway involves electrophilic or nucleophilic attack between two farnesyl diphosphates (FPPs) leading to direct or indirect formation of a C30 botryococcene via a cyclobutane ring intermediate (1′-2-3-2′ cyclisation). A Retro-Prins reaction and subsequent methylation gives rise to C29 and C33 botryococcenes in sequence. The geochemical component involves first in-water-column (photo)-oxidation of the alkene to a C33 botryococcanone and subsequent reduction (hydrogenation) to stabilize the ketone as an alkane.

8142. 题目: Significant chemical fluxes from natural terrestrial groundwater rival anthropogenic and fluvial input in a large-river deltaic estuary
文章编号: N18080816
期刊: Water Research
作者: Xin Luo, Jiu Jimmy Jiao, Willard S. Moore, John A. Cherry, Ya Wang, Kun Liu
更新时间: 2018-08-08
摘要: The shores of the Pearl River estuary are home to 35 million people. Their wastes are discharged into the large river delta-front estuary (LDE), one of the most highly polluted systems in the world. Here we construct a radium reactive transport model to estimate the terrestrial groundwater discharge (TGD) into the highly urbanized Pearl River LDE. We find the TGD comprises only approximately 0.9% in term of water discharge compared to the river discharge. The TGD in the Pearl River LDE delivers significant chemical fluxes to the coast, which are comparable to the fluvial loadings from Pearl River and other world major rivers. Of particular importance is the flux of ammonium because of its considerable role in Pearl River estuary eutrophication and hypoxia. Unlike the ammonium in many other aquifers, the ammonium in the Pearl River aquifer system is natural and originated from organic matter remineralization by sulfate reduction in the extremely reducing environment. The TGD derived NH4+ is as much as 5% of the upstream Pearl River fluvial loading and 42% of the anthropogenic inputs. This high groundwater NH4+ flux may greatly intensify the eutrophication, shift the trophic states, and lead to alarming hypoxia within the affected ecosystems in the Pearl River LDE. The large TGD derived chemical fluxes will lead to deterioration of water and will potentially affect human health.

8143. 题目: Erosion-induced carbon losses and CO2 emissions from Loess and Black soil in China
文章编号: N18080815
期刊: CATENA
作者: Xin Gao, Yaxian Hu, Qiqi Sun, Lanlan Du, Pengfei Duan, Lunguang Yao, Shengli Guo
更新时间: 2018-08-08
摘要: Soil erosion influences both lateral soil organic carbon (SOC) re-distribution and vertical soil CO2 emissions. While potential SOC mineralization during transport and the burial effects of SOC at depositional sites have been addressed in previous reports, erosion induced on-site CO2 emissions are still under-studied. In this study, two soils (Loess soil and Black soil) with similar texture but contrasting aggregate structure and SOC content were subject to a set of 60-min long simulated rainfall events. There were two different rainfall intensities (30 and 90 mm h−1) at three slope gradients (5°, 15° and 25°). Runoff and sediment from erosion plot were collected at 10-min intervals over 60 min. Soil CO2 emissions from eroding slopes, SOC and particle size distribution of the eroding soil were measured after the erosion events. The results show that the runoff rates from the two soils were comparable, but the sediment rates from the Loess soil roughly three times that from the Black soil. In general, the SOC erosion from the Loess soil was 1.8 times that from the Black soil, even though the SOC concentration in the original Black soil was 56% higher than the Loess soil. The cumulative soil CO2 emissions from the eroding slopes of the Loess soil ranged from 15.4 to 19.7 g C m−2, which was doubled on the Black soil (from 28.1 to 59.6 g C m−2). When the rainfall intensity raised from 30 mm h−1 to 90 mm h−1, the cumulative soil CO2 emissions from the Black soil decreased by 38.2%, but only declined by 10.0% on the Loess soil. When the slope gradient increased from 5° to 25°, the cumulative soil CO2 emissions decreased by 23.8% on the Black soil but by 12.6% on the Loess soil. Therefore, our observations suggest that the soil CO2 emissions on the Black soil was much more sensitive to the variations of rainfall intensity and slope gradients than the Loess soil. Greater SOC erosion should not be directly translated to less on-site soil CO2 emissions. The selective depletion/enrichment of SOC and the lability of individual components must be fully understood when accounting for slope-scale carbon balances.

8144. 题目: Spatial variation of heavy metals in sediments within a temperate mangrove ecosystem in northern New Zealand
文章编号: N18080814
期刊: Marine Pollution Bulletin
作者: Ujwal Bastakoti, John Robertson, Andrea C. Alfaro
更新时间: 2018-08-08
摘要: Spatial dynamics of heavy metals (Cd, Cu, Fe, Pb, and Zn) and metalloid As were investigated along the sedimentary column, inside and outside mangrove stands, and within the upper, middle, and lower Mangawhai Estuary, New Zealand. Organic matter contents (1.89 to 17.15%) were 10 times higher inside versus outside mangroves, and decreased sharply with depth to 30 cm. Cu, Fe, and Zn were highest in the upper estuary and Pb was highest close to a road (lower estuary), reflecting road run-off. A mangrove island (lower estuary; high energy) had lowest heavy metal and highest As concentrations (resulting from high absorption of As by the carbonate rich sediments). Most of the analysed sediment parameters in our study were higher inside versus outside mangroves, suggesting the accumulation of organic matter and build up capacity to buffer pollutants. Our results show that mangrove stands tend to accumulate heavy metals and may act as natural filters of pollution of coastal waterways.

8145. 题目: Role of extracellular polymeric substances in efficient chromium(VI) removal by algae-based Fe/C nano-composite
文章编号: N18080813
期刊: Chemosphere
作者: Jun Wu, Lin-Lin Ma, Raymond J. Zeng
更新时间: 2018-08-08
摘要: Subsequent application of the obtained algae by chemical coagulation (e.g. Fe(III) addition) presents a challenge because of various iron compounds in algae. In this study, algae obtained by chemical coagulation were carbonized to yield an algae-based Fe/C nano-composite with a high capacity for hexavalent chromium (Cr(VI)) removal (236.9 mg/g), which is attributed to the high reductive Fe content (e.g., FeS, Fe(0), and FeO) and specific surface area. The optimal conditions—that is, 100 mg/L Fe(III) addition and 800 °C—were determined. Moreover, the role of extracellular polymeric substances (EPS) in carbonization was examined as it affected the product composition and efficiency of Cr(VI) removal, owing to the stabilizing property effect of EPS in algae. Algal EPS induced the homogeneous distribution of Fe compounds on the surface of the algae, and the generated α-FeOOH nanoparticles were wrapped in organic carbon matrix, resulting in a sufficient reaction between Fe compounds and organic carbon during carbonization. X-ray photoelectron spectroscopy showed that reduction and adsorption contributed 83.44% and 16.56% to Cr(VI) removal, respectively. This study provides a new insight into the role of EPS in the efficient Cr(VI) removal by algae-based Fe/C nano-composite and presents a promising application of this Fe/C nano-composite in environmental remediation.

8146. 题目: Insight into mechanism of aged biochar for adsorption of PAEs: Reciprocal effects of ageing and coexisting Cd2+
文章编号: N18080812
期刊: Environmental Pollution
作者: Fanqi Jing, Saran P. Sohi, Yuyan Liu, Jiawei Chen
更新时间: 2018-08-08
摘要: Biomass derived biochar is a stable carbon-rich product with potential for soil amendment. Introduced into the natural environment, biochar will naturally experience ‘ageing’ processes that are liable to change its physicochemical properties and the mobility of sorbed pollutants over the longer term. To elucidate the reciprocal effects of biochar ageing and heavy metal adsorption on the affinity of biochar for organic pollutants, we systematically assessed the adsorption of diethyl phthalate (DEP), representative of phthalic acid esters (PAEs), to fresh and aged biochars with and without coexistence of Cd2+. Long-term oxidative ageing was simulated using 5% H2O2 and applied to biochar samples made from corn cob, maize straw and wheat straw made by pyrolysis at both 450 °C and 650 °C. Our results showed that biochar made at lower temperature (450 °C) and from straw exhibited the higher adsorption capacity, owing to their greater polarity and abundance of O-containing functional groups. The adsorption of DEP onto fresh biochars was found to be driven by van der Waals force and H-bonding. Biochar made at the higher temperature (650 °C) displayed higher carbon stability than that produced at lower pyrolysis temperature. Oxidized biochar showed lower adsorption capacity than fresh biochar owing to the formation of three-dimensional water clusters on biochar surface, which blocked accessible sites and decreased the H-bonding effect between DEP and biochars. The coexistence of Cd2+ suppressed the sorption of DEP, via competition for the same electron-rich sites. This indicates that cation/π-π EDA interactions are the primary mechanism for PAE and Cd2+ stabilization on biochar. Our study sheds light on the mechanism of organic pollutant sorption by biochar, as well as the potential susceptibilities of this sorption to ageing effects in the natural environment.
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8147. 题目: A comprehensive probabilistic approach for integrating natural variability and parametric uncertainty in the prediction of trace metals speciation in surface waters
文章编号: N18080811
期刊: Environmental Pollution
作者: P. Ciffroy, M. Benedetti
更新时间: 2018-08-08
摘要: The main objectives of this study were to evaluate global uncertainty in the prediction of Distribution coefficients (Kds) for several Trace Metals (TM) (Cd, Cu, Pb, Zn) through the probabilistic use of a geochemical speciation model, and to conduct sensitivity analysis in speciation modeling in order to identify the main sources of uncertainty in Kd prediction. As a case study, data from the Loire river (France) were considered. The geochemical speciation model takes into account complexation of TM with inorganic ligands, sorption of TM with hydrous ferric oxides, complexation of TM with dissolved and particulate organic matter (i.e. dissolved and particulate humic acids and fulvic acids) and sorption and/or co-precipitation of TM to carbonates. Probability Density Functions (PDFs) were derived for physico-chemical conditions of the Loire river from a comprehensive collection of monitoring data. PDFs for model parameters were derived from literature review. Once all the parameters were assigned PDFs that describe natural variability and/or knowledge uncertainty, a stepwise structured sensitivity analysis (SA) was performed, by starting from computationally ‘inexpensive’ Morris method to most costly variance-based EFAST method. The most sensitive parameters on Kd predictions were thus ranked and their contribution to Kd variance was quantified. Uncertainty analysis was finally performed, allowing quantifying Kd ranges that can be expected when considering all the sensitive parameters together.
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8148. 题目: Impact of microbial activity on the mobility of metallic elements (Fe, Al and Hg) in tropical soils
文章编号: N18080810
期刊: Geoderma
作者: C. Balland-Bolou-Bi, E.B. Bolou-Bi, V. Alphonse, S. Giusti-Miller, M.D. Jusselme, A. Livet, M. Grimaldi, N. Bousserhine
更新时间: 2018-08-08
摘要: Dissolved organic carbon (DOC), especially low molecular mass organic acids (LMMOAs) derives principally from biota degradation process in which soil microorganisms are the main actors and from roots exudates. The presence of LMMOAs led to an increase of availability and mobility of metallic elements through the formation of organo-metallic complex. In tropical soils, very few information about LMMOAs quantification and their role in the biogeochemical process related to trace metals cycling was available. Quantification of LMMOAs is limited due to their low concentration and rapid degradation. Until now, the role of microbial activity as well as LMMOAs in the biogeochemical cycle of metallic elements in tropical soils has not been investigated. The present study was conducted to evaluate the effect of microbial activity and biomass on the availability and mobility of metallic elements (Fe, Al and Hg) in two tropical soils, Ferralsol and Acrisol. We also quantified LMMOAs contents in soil solutions and addressed to their role in the mobilization of metals.Utilization of Diffuse Gradient in Thin film (DGT) method permits to analyze bioavailable metal in both fractions: organically complexed and free metals. The results show that the quantity of Fe, Al and Hg labile were higher in Ferralsol than Acrisol soils. This was more accentuated for the 50 cm-depth of soils where the microbial activities and the organic carbon content were important. Concentration of LMMOAs of Ferralsol and Acrisol were lower in compare to coniferous and deciduous forest soils. Proportions of LMMOAs in DOC were very small at 10.5% and 6.85% in the Ferralsol and Acrisol soils, respectively. The mobilization of Fe, Al and Hg in Ferralsol and Acrisol soils appeared to vary depending on the soil physico-chemical characteristics (sorption capacities and metals content) and also on the microbial biomass and activity. Soil pH influences the acidity of the functional groups in organic molecules and consequently their speciation. In addition, low pH increase proton competition within acidic functional groups involved in coordinate bond. The content of CEC in Ferralsol is higher than Acrisol that is related to the high contents of clay and organic carbon. Low CEC content can result in a decrease of retain of the cationic trace metals. Low CEC content led to a decrease of the capacity of retaining of metallic elements in tropical soils in compare to temperate soils.

8149. 题目: Baseline map of soil organic carbon in Tibet and its uncertainty in the 1980s
文章编号: N18080809
期刊: Geoderma
作者: Y. Zhou, R. Webster, R.A. Viscarra Rossel, Z. Shi, S. Chen
更新时间: 2018-08-08
摘要: Much of the carbon (C) stored in the soil of the high Qinghai–Tibet Plateau could be lost as a result of global warming. To provide a baseline against which to assess the loss we have made a new map at 90-m resolution from sample data of 1148 soil profiles augmented by information on climate, vegetation, physiography and digital elevation. We used the program Cubist, which works as a form of regression tree, to predict the concentration at the nodes of the 90-m grid. The uncertainty of the predictions was computed by bootstrapping 50 times at each node. Soil type, evapotranspiration (ET), precipitation, radiation and vegetation type contributed most to the variation in C at the coarse scale; temperature, net primary productivity, normalized difference vegetation index (NDVI), ET and elevation contributed most at finer scales. We mapped the predicted concentration of C and converted the predictions to stocks of C for the main kinds of land: 1.93 Pg for the alpine steppe, 1.57 Pg for the meadow, 0.66 Pg in the coniferous forest, 0.63 Pg in the broadleaf forest, 1.06 Pg under shrub, < 0.4 Pg for each of the alpine desert and cropland. We estimate the uppermost 30 cm of soil to contain 6.81 Pg of C with 95% (3.80 to 10.27 Pg). This estimate differs substantially from the two previous coarser estimates based on global modelling which far exceed our 95% upper confidence limit. Our new estimate can now serve as a base against which to judge any change of soil C as a response to global warming.

8150. 题目: Environmental safety data on CuO and TiO2 nanoparticles for multiple algal species in natural water: Filling the data gaps for risk assessment
文章编号: N18080808
期刊: Science of The Total Environment
作者: Elise Joonas, Villem Aruoja, Kalle Olli, Anne Kahru
更新时间: 2018-08-08
摘要: Most research on nanoparticle (NP) ecotoxicological effects has been conducted on single species in laboratory conditions that are not environmentally representative. We compared the effects of CuO NPs, CuSO4 (ionic control) and TiO2 NPs in nutrient-adjusted natural water (ANW) and in the OECD201 standard medium to four different algal species: green algae Raphidocelis subcapitata and Chlamydomonas reinhardtii, a diatom Fistulifera pelliculosa, and a cyanobacterium Synechocystis sp. Biomass and the effective quantum yield of photosystem II (Fv/Fm) were used as toxicity endpoints. CuO NPs were very toxic across taxa in the OECD201 assay (biomass-based 72 h EC50 0.2–0.9 mg l−1). Toxicity of CuO NPs was explained by shedding of ions from particles as Cu2+ is highly toxic: 72 h EC50 in the OECD201 medium was 0.01–0.03 mg l−1 in three species and 0.003 mg l−1 in the case of the cyanobacterium. Toxicity of copper compounds was overall reduced in ANW, presumably because of reduced bioavailability due to metal ions binding to natural organic matter. Copper compounds were more toxic to the cyanobacterium than to other algae and this effect was not amended in ANW. TiO2 NPs did not inhibit the biomass production and photosynthesis of the diatom or the cyanobacterium up to 100 mg l−1, but inhibited biomass production of green algae in the OECD201 medium (EC50 14–15 mg l−1). TiO2 NPs also did not significantly inhibit Fv/Fm up to 100 mg l−1, suggesting a general lack of effect on photosynthesis. Adverse effects of TiO2 NPs were at least in part due to cell-NP heteroagglomeration. Our data are informative for the complete risk assessment of engineered NPs by filling data gaps about NP effects in environmentally realistic conditions.
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8151. 题目: The impact of woodchip-gravel mixture on the efficiency and toxicity of denitrification bioreactors
文章编号: N18080807
期刊: Science of The Total Environment
作者: Michal Šereš, Klára Anna Mocová, Jabbar Moradi, Michal Kriška, Vladimír Kočí, Tereza Hnátková
更新时间: 2018-08-08
摘要: Woodchip-based denitrification bioreactors are widely used for treatment of high loads of nitrate pollution in agricultural run-off water. A concern raised recently, as a consequence of various organic fillings being experimented with, is whether the positive effect given by nitrate reduction could override the negative effects of such bioreactors, mainly caused by degradation of wood and the production of potentially harmful conditions for aquatic ecosystems. This paper presents the results of the experimental testing of two different filling materials: birch (BWCH) and spruce (SWCH) woodchip, and their mixture with washed gravel (WG) in volumetric ratio 10:1. We have focused on the leaching of organic carbon and phenols, and its impact on selected aquatic organisms, as well as on their denitrification efficiency and NO3 load removal rate (LRT). The results show that TOC, DOC and FNI (phenolic index) leaching is higher for the pure woodchip materials and is closely correlated with the growth inhibition of tested organisms (Vibrio fischeri, Daphnia magna, Desmodesmus subspicatus, Lemna minor). The highest denitrification efficiency and the highest load removal rates were recorded in mixed filling material (96% and 1.4 mg NO3·dm3·d−1 for WG:BWCH; 85% and 1.2 mg NO3·dm3·d−1 for WG:SWCH). Denitrification bioreactors with mixed woodchip filling material present a promising, cheap, and extensive technology for the treatment of agricultural field run-offs.
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8152. 题目: Distributions and pools of lead (Pb) in a terrestrial forest ecosystem with highly elevated atmospheric Pb deposition and ecological risks to insects
文章编号: N18080806
期刊: Science of The Total Environment
作者: Jun Zhou, Buyun Du, Zhangwei Wang, Wantong Zhang, Lei Xu, Xingjun Fan, Xiaoli Liu, Jing Zhou
更新时间: 2018-08-08
摘要: There is growing interest in how heavy metals in remote ecosystems are elevated and affect environmental health. However, no studies have investigated atmospheric lead (Pb) deposition influences on the Pb bioaccumulation in insects in forests. Here we measure Pb concentrations and pools in forest vegetation, litterfall, organic soil, mineral soil, as well as litterfall deposition fluxes in a region severely affected by atmospheric deposition. We also analyzed Pb in insects which feed in the polluted forest vegetation and litter. Assessment of high Pb loads causing potential ecological risk to insects was also studied. Total Pb pool in the vegetation was 0.12 g m−2 and annual litterfall deposition flux of Pb was 13.42 mg m−2, which was much higher than those in the background areas. Pools of Pb from litter to mineral topsoil averaged 4.3 g m−2, which accounted for 97.3% of total pools (biomass + soil) in the forest ecosystem. Pools of Pb in surface soils were correlated significantly with the pools of total organic matter and elevation. Atmospheric deposition was inferred the major source of Pb in the forest ecosystem, which can be supported by the highest Pb concentrations in the moss and overstory foliage. The maximum Pb concentration was showed in the dung beetle (12.1 mg kg−1) residing in the soils compared that in the longicorn and of cicada, which would potentially pose negatively influence to predators along food chains.
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8153. 题目: Assessment of fungi proliferation and diversity in cultural heritage: Reactions to UV-C treatment
文章编号: N18080805
期刊: Science of The Total Environment
作者: Stéphane Pfendler, Battle Karimi, Laurence Alaoui-Sosse, Faisl Bousta, Badr Alaoui-Sossé, Mohamed M. Abdel-Daim, Lotfi Aleya
更新时间: 2018-08-08
摘要: Fungi are present in natural and non-touristic caves due to the presence of organic matter provided mainly by insects or animals such as bats. In show caves, however, tourist infrastructure and the visitors themselves are an important source of organic matter. In addition, photosynthetic biofilms provide a high amount of carbon and nitrogen sources for fungi. This study was conducted to identify the fungal communities present in caves along with the potential use of UV-C treatment against their proliferation. Thus, fungal communities proliferating in biofilms in six French and Swiss show caves were analyzed using high throughput sequencing. The results show 385 species recorded, some of them previously described in cases of fungal outbreak. This preliminary study also aimed to test the use of UV-C light as an environmentally friendly method to treat fungal proliferation. Six fungal strains, from three different sources (Lascaux cave, La Glacière cave, a church in Vicherey, France), were cultivated in an agar dish. Spores, mycelia and the entire colony were irradiated using several UV-C intensities. Results showed that four of the six fungi spores and mycelium died following a low-intensity UV-C treatment (2 kJ m−2, 160 s), though Ochroconis lascauxensis and Penicillium bilaiae spores showed higher resistance. Finally, it was demonstrated that the fungal colony could resist the UV-C light due to a shadow effect. The structure of the fungal colony was affected from the periphery to its inner part. However, after four 30 kJ m−2 treatments (39 min irradiation) all strains there definitively eradicated. Further studies will be necessary to examine the potential of UV-C light under cave conditions as a preventive and curative treatment.
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8154. 题目: Reactive Photo-Fenton ceramic membranes: Synthesis, characterization and antifouling performance
文章编号: N18080804
期刊: Water Research
作者: Shaobin Sun, Hong Yao, Wanyi Fu, Likun Hua, Guangshan Zhang, Wen Zhang
更新时间: 2018-08-08
摘要: To develop reactive and antifouling membrane filtration systems, a photo-Fenton ceramic membrane was prepared by coating goethite (α-FeOOH) catalysts on a zirconia/titania alumina membrane via a cross-linking method. Scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to characterize α-FeOOH catalysts and the surface coating quality. The cross linker yielded stable covalent binding between catalyst and membrane under room temperature and produced a homogeneous and smooth coating of catalyst on ceramic membranes. Photo-Fenton reactions were initiated with addition of H2O2 under UV irradiation to improve the foulant degradation on membrane surface while filtration. Membrane fouling was simulated by bovine serum albumin (BSA) and humic acid (HA). Our results show that the photo-Fenton reactions on the coated membranes slowed down the fouling kinetics and even reversed the fouling, leading to a stable transmembrane pressure (TMP) over time of filtration, as opposed to a monotonous increase of TMP due to surface fouling. The batch experiments verified that the photo-Fenton reactions achieved the degradation rates of 76% and 86% for HA and BSA respectively within 60 min, with the mineralization rates of over 80% as indicated by the total organic carbon measurement. This study embarks on a novel antifouling membrane filtration process via incorporation of photo-Fenton reactions. The findings are also important for diverse applications of surface fouling mitigation and rationale design of fouling resistant surfaces or materials through photo-Fenton or other catalytic reactions.
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8155. 题目: Electrochemical filtration process for simultaneous removal of refractory organic and particulate contaminants from wastewater effluents
文章编号: N18080803
期刊: Water Research
作者: Naresh Mameda, Hyeona Park, Kwang-Ho Choo
更新时间: 2018-08-08
摘要: Versatile electrochemical reactions are effective for removing a wide range of water contaminants. This study focuses on the development and testing of bifunctional electrocatalytic filter anodes as reactive and separating media for the simultaneous removal of refractory dissolved organic and particulate contaminants from real wastewater effluents. The results show that the TiO2 particle interlayers formed between the Ti fiber support and the top composite metal oxide catalyst layers assist in reducing filter pores to an effective size range that enables removal of most particulates within the wastewater. The double-sheet design, which is a sandwich-structured module with an internal void space for permeate, prevents filter fouling, and transmembrane pressure can be maintained at a very low level of <5 kPa during batch and continuous flow reactor operations. Substantive and simultaneous removal of dissolved organics (e.g., chromophores, fluorophores, 1,4-dioxane, chemical oxygen demand, and total organic carbon) and particulate matter (i.e., turbidity) are achieved, although removal rates and efficacies differ depending on the electric current density applied. Decolorization and particulate rejection occur swiftly and immediately, but 1,4-dioxane degradation is relatively slow and quite time-dependent. Possible 1,4-dioxane degradation pathways during electrocatalysis are also proposed. Electrochemical filtration technology shows considerable promise for use in the next generation of advanced wastewater treatment solutions.
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8156. 题目: Influence of polysaccharides on the dynamic self-assembly of medium-chain fatty acid vesicles and hydrolysis of decanoic acid anhydrides
文章编号: N18080802
期刊: Colloids and Surfaces A: Physicochemical and Engineering Aspects
作者: Ming-Qiang Jia, Qi-Zheng Liu, Li-Juan Zhu, Yan Zhang, Zhong-Xiu Chen
更新时间: 2018-08-08
摘要: Hydrolysis of fatty acid anhydrides involves fatty acid vesicle formation and autocatalytic hydrolysis. Previous studies focused on the effect of biopolymers on vesicle formation or on autocatalytic reactions, however, the influence of polysaccharides on a system where the self-assembly of fatty acid vesicles and the hydrolysis of fatty acid anhydrides coexist remains unknown. In this paper, three polysaccharides, sodium chondroitin sulfate (CSA), sodium alginate (SA) and 2-hydroxyethyl cellulose (2-HEC) were selected to investigate the effect of crowded media on the decanoic acid vesicle formation and the autocatalytic hydrolysis of decanoic anhydride. The results showed that the rate of hydrolysis of decanoic anhydride increased in CSA or SA but decreased in 2-HEC. Further investigation revealed that the size of vesicles in CSA decreased in the early stage of vesicle formation but increased in 2-HEC. In the CSA-vesicle system, elastic behavior dominates, while 2-HEC- and SA-vesicles show more viscous behavior. In addition, the significantly increased membrane fluidity in CSA or in SA supports self-assembly of decanoic acid vesicles and autocatalytic hydrolysis, which is the opposite in the case of 2-HEC. This research provides new insights into the self-assembly of fatty acid vesicles and vesicle-catalyzed reactions with polysaccharides in crowded conditions.
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8157. 题目: Remineralization rate of terrestrial DOC as inferred from CO2 supersaturated coastal waters
文章编号: N18080801
期刊: Biogeosciences
作者: Filippa Fransner, Agneta Fransson, Christoph Humborg, Erik Gustafsson, Letizia Tedesco, Robinson Hordoir, and Jonas Nycander
更新时间: 2018-08-08
摘要: Coastal seas receive large amounts of terrestrially derived organic carbon (OC). The fate of this carbon, and its impact on the marine environment, is however poorly understood. Here we combine underway CO2 partial pressure (pCO2) measurements with coupled 3D hydrodynamical-biogeochemical modelling to investigate whether remineralization of terrestrial dissolved organic carbon (tDOC) can explain CO2 supersaturated surface waters in the Gulf of Bothnia, a subarctic estuary. We find that a substantial remineralization of tDOC, and that a strong tDOC induced light attenuation dampening the primary production, is required to reproduce the observed CO2 supersaturated waters in the nearshore areas. A removal rate of tDOC of the order of one year, estimated in a previous modelling study in the same area, gives a good agreement between modelled and observed pCO2. The remineralization rate is on the same order as bacterial degradation rates calculated from published incubation experiments, suggesting that this remineralization could be caused by bacterial degradation. Furthermore, the observed high pCO2 values during the ice covered season argues against photochemical degradation as the main removal mechanism. All of the remineralized tDOC is outgassed to the atmosphere in the model, turning the northernmost part of the Gulf of Bothnia to a source of atmospheric CO2.

8158. 题目: Compost Humic Acid-Like Isolates from Composting Process as Bio-based Surfactant: Properties and Feasibility to Solubilize Hydrocarbon from Crude Oil Contaminated Soil
文章编号: N18080712
期刊: Journal of Environmental Management
作者: Gina Lova Sari, Yulinah Trihadiningrum, Dwiyanti Agustina Wulandari, Ellina Sitepu Pandebesie, I.D.A.A. Warmadewanthi
更新时间: 2018-08-07
摘要: Biodecomposition of organic solid waste during composting process produces compost humic acid-like (cHAL), which is classified as biobased surfactant. The present study aimed to characterize the properties of cHAL substance which was formed during the composting process of crude oil contaminated soil, in terms of surface tension decline (∆ST) and emulsification activity (EA), and evaluate the ability to solubilize hydrocarbons. Crude oil contaminated soil from a public oilfield in Wonocolo Sub-district, Bojonegoro, Indonesia, was composted under aerobic condition with varied biodegradable waste (yard waste and rumen residue) in separate reactors. The cHAL compounds were isolated from composting products from yard waste (Y100), rumen residue (R100), control of contaminated soil (S100), and mixed of contaminated soil and biodegradable waste (S50YR50). The results showed that ∆ST of cHAL isolates were ranged from 6.65 to 21.50 mN/m. The EA of cHAL isolates were in the range of 7.35–38.01%. The cHAL isolates were capable to solubilize 99 to 10,710 µg/g of hydrocarbons. The cHAL isolates from R100 and S50YR50 are potential as surface tension reducer and emulsifier for hydrocarbon with values of those isolates were close to 0.50% Tween 80 characteristics, and the abilities to solubilize hydrocarbon were comparable to 1.00% Tween 80. A composition of 50% crude oil contaminated soil and 50% of biodegradable waste (yard waste and rumen residue) is recommended for composting crude oil contaminated soil.

8159. 题目: Prediction models for evaluating the uptake of heavy metals by cucumbers ( Cucumis sativus L.) grown in agricultural soils amended with sewage sludge
文章编号: N18080711
期刊: Environmental Monitoring and Assessment
作者: Ebrahem M. Eid, Sulaiman A. Alrumman, Emad A. Farahat, Ahmed F. El-Bebany
更新时间: 2018-08-07
摘要: Heavy metal (HM) concentrations in edible plants can develop many serious health risks to humans. The precise prediction of plant uptake of HMs is highly important. Thus, the present investigation was carried out to develop regression models for predicting the concentrations of HMs in cucumbers (Cucumis sativus L.) from their concentration in the soil and using the organic matter (OM) content and soil pH as co-factors. The results showed that cucumber roots had the highest significant concentrations of all HMs at P < 0.001, except Cd, Cu, and Zn were in fruits. The lowest concentrations of Cd, Co, Cr, Mn, Ni, and Pb were recorded in stems. HM concentrations in cucumbers were strongly correlated with soil HM, pH, and OM content. Soil pH and OM content had negative and positive correlations with all HMs in cucumber tissues, respectively. Regression analysis indicated that soil HM, pH, and OM contents were good predictors for HM concentrations in cucumbers. The regression models for root Co, Cr, Fe, and Zn were described by high model efficiency values that explain 48–58% variability. The best regression models for cucumber stem were for Cu, Mn, Ni, and Zn that are characterized by high R2 and model efficiency values. For cucumber fruits, R2 values were ranged from 54 to 82%, with best models for Cr, Pb, Cd, Cu, Ni, and Co in the fruit. We expect that these models will be beneficial for risk assessment studies on sewage sludge utilization in agriculture.

8160. 题目: Molecular biomarkers in the subsurface of the Salar Grande (Atacama, Chile) evaporitic deposits
文章编号: N18080710
期刊: Biogeochemistry
作者: Laura Sánchez-García, Christoph Aeppli, Victor Parro, David Fernández-Remolar, Miriam García-Villadangos, Guillermo Chong-Diaz, Yolanda Blanco, Daniel Carrizo
更新时间: 2018-08-07
摘要: The Late Miocene–Pliocene aged hyperarid evaporitic system of Salar Grande is a unique, halite-rich sedimentary basin in the Cordillera de la Costa of the Central Andes (Chile) whose bio-sedimentary record is poorly understood. The persistence of hyperacidity over millions of years, the hypersalinity, and the intense UV radiation make it a terrestrial analogue to assess the potential presence of organic matter in the halite deposits found on Mars. We investigated the occurrence and distribution of biomolecules along a 100-m depth drill down to the ~ 9 Ma old detrital deposits topped by La Soledad Formation (ESF). We have identified two well-defined mineralogical and geochemical units by X-ray diffractometry (XRD) and ion chromatography: a nearly pure halite down to 40 m, and a detrital one down to 100 m depth. One-dimensional GC–MS and two-dimensional GC × GC-TOF–MS gas chromatography–mass spectrometry techniques allowed us to detect a variety of lipidic compounds (n-alkanes, n-alkanols, isoprenoids, steroids, and hopanoids), and a relative abundance of functionalized hydrocarbons (n-fatty acids or n-aldehydes), mostly in the upper halite. We also detected biopolymers and microbial markers by fluorescence sandwich-microarray immunoassays. A dominant prokaryotic origin was associated with halophile bacteria and archaea, with minor contributions of lichens, macrophytes, or higher plants. The lipidic record was also imprinted by oxic (high pristane over phytane ratios) and saline (squalane, and mono-methyl n-alkanes) signatures. The vertical abundance and distribution of biomarkers in the Salar Grande was explained by a generalized effect of xeropreservation, combined with salt encapsulation in the upper halite deposits, or with protective organics-mineral interactions in the deeper detrital unit. The results contribute to the interpretation of terrestrial bio-sedimentary records of halite deposits and their association to environmental conditions. The high potential for preservation of biosignatures at Salar Grande suggests that similar evaporitic deposits in Mars should be priority targets for searching for signs of life.

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