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9501. 题目: Impact of water quality parameters on bacteria inactivation by low-voltage electroporation: mechanism and control
文章编号: N18060104
期刊: Environmental Science: Water Research & Technology
作者: Zheng-Yang Huo, Guo-Qiang Li, Tong Yu, Yun Lu, Hao Sun, Yin-Hu Wu, Cecilia Yu, Xing Xie, Hong-Ying Hu
更新时间: 2018-06-01
摘要: Nanowire-assisted low-voltage electroporation enables efficient and energy-conserving bacteria inactivation without byproduct formation. This approach is promising for replacing traditional methods for reliable water disinfection. Nevertheless, studies of applying this approach to different water matrices have not yet been done. Here, we study the effect of primary water quality parameters (pH, ionic strength, ion type, and organic matters) on the effectiveness of bacteria inactivation by low-voltage electroporation. Our results show that while pH, ionic strength, and ion type cause little impact, high concentration (>5 mg L-1) of macromolecular organic matter (>5000 g mol-1) hampers the disinfection performance. These macromolecular organic matters tend to accumulate around or attach to the nanowires and hinder the bacteria from reaching the regions with enhanced electric field strength where inactivation occurs. Electrochemical reduction of the organic matters further reduces their solubility, resulting in more precipitation on the nanowires. To reduce such negative impacts, we have proposed and verified that applying alternating current instead of direct current can slow down the accumulation and electrochemical precipitation.
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9502. 题目: Degradation mechanisms of cefotaxime using biochar supported Co/Fe bimetallic nanoparticles
文章编号: N18060103
期刊: Environmental Science: Water Research & Technology
作者: Hongwei Wu, Qiyan Feng, Ping Lu, Meng Chen, Hong Yang
更新时间: 2018-06-01
摘要: Ecological risks caused by residual antibiotics have increasingly attracted great attention. In this study, a highly efficient novel adsorbent based on Co/Fe bimetallic nanoparticles loaded with alkali modified biochar (Co/Fe/MB) was prepared to remove cefotaxime from an aqueous solution. The prepared composites were characterized with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of Co loading, adsorbent dosage, initial solution pH and anions (Cl-, HCO3- and EDTA) on the removal of cefotaxime were investigated. Due to the synergetic reaction of the adsorption and reduction mechanism, Co/Fe/MB revealed the highest cefotaxime removal efficiency (99.23%) in 100 min at the condition of pH = 5, T = 298 K, Co/Fe/MB dosage = 0.8 g L-1, Co loading = 0.4 wt%, cefotaxime = 20 mg L-1. The removal efficiency was further enhanced in the presence of EDTA and Cl- because of the destruction of a passivation layer on iron surface. Additionally, the degradation products and possible degradation pathway of cefotaxime by Co/Fe/MB were analyzed by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). The spectra revealed that the opening and cleavage of the β-lactam ring was the first step for cefotaxime degradation. The Co/Fe/MB composite was found to be an efficient material to remove cefotaxime from the solution.
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9503. 题目: Carbon biogeochemistry of a flooded Pantanal forest over three annual flood cycles
文章编号: N18060102
期刊: Biogeochemistry
作者: Higo J. Dalmagro, Michael J. Lathuillière, Iain Hawthorne, Douglas D. Morais, Osvaldo B. Pinto Jr, Eduardo G. Couto, Mark S. Johnson
更新时间: 2018-06-01
摘要: The Pantanal is the largest wetland in the world and yet little is known about the variability in carbon (C) dynamics across its flood seasons. We examined the effect of inundation on the C cycle in the 2013–2015 flood cycles illustrated by dissolved CO2, CH4, organic C (DOC) concentration measurements, and optical properties of dissolved organic matter (DOM) evaluated by absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC). During the 2015 flood cycle, pCO2 varied between 5973 and 14,292 μatm, with pCH4 concentrations ranging between 2956 and 51,675 μatm respectively, with high temporal variability for both gases. The supersaturation of CO2 and CH4 in relation to the atmospheric equilibrium caused the system to behave as a net source of CO2 and CH4 to the atmosphere with evasion rates of 320 mg CO2 m-2 d-1 and 20 mg CH4 m-2 d-1, respectively. Mean DOC concentration was 7.0 ± 0.4 mg L-1 and did not differ between flood cycles. Higher concentrations of DOC were measured at the start (rising floodwaters) and at the end (receding floodwaters) of flood cycles, while lower DOC concentrations were observed during the peak flood. The PARAFAC analysis indicated the presence of five DOM components: humic (C1 and C2) and fulvic type material (C3) showed the highest relative abundance (68.5% of the total PARAFAC component fluorescence), as well as protein-like material (C4 and C5) derived from microorganisms. Our measured diffusive flux levels were below the range of emissions found for wetlands and floodplains for CO2, but were slightly higher for CH4 relative to other studies in lakes and seasonally flooded areas of the Pantanal. The large variations in concentrations of CO2, CH4 and DOC and the optical properties of DOM during the course of each flood cycle suggest a close relationship between carbon and water cycles in this tropical wetland.

9504. 题目: High variability in iron-bound organic carbon among five boreal lake sediments
文章编号: N18060101
期刊: Biogeochemistry
作者: Simone Peter, Sebastian Sobek
更新时间: 2018-06-01
摘要: Being both stable carbon sinks and greenhouse gas sources, boreal lake sediments represent significant players in carbon (C) cycling. The release of dissolved organic carbon (DOC) into anoxic water is a widespread phenomenon in boreal lakes with impact on sediment C budgets. The association of OC with iron (Fe) is assumed to play an important role for this anoxic OC release via the dissimilatory reduction of Fe, but also to influence the stabilization of OC in sediments. To investigate the role of Fe–OC association for OC dynamics in different boreal lake sediments, we compared the content of Fe-bound OC [Fe–OC, defined as citrate bicarbonate dithionite (CBD) extractable OC] and the extent of reductive dissolution of solid-phase Fe and OC at anoxia. We found high among-lake variability in Fe–OC content, and while the amount of Fe–OC was high in three of the lakes (980–1920 mol g-1), the overall contribution of Fe–OC to the sediment OC pool in all study lakes was not higher than 11%. No linkages between the amount of the Fe–OC pool and lake or sediment characteristics (e.g., pH, DOC concentration, sediment OC content, C:N ratio) could be identified. The observed release of OC from anoxic sediment may be derived from dissolution of Fe–OC in the lake sediments with high Fe–OC, but in other lake sediments, OC release during anoxia exceeded the sediment Fe–OC pool, indicating low contribution of reductive Fe dissolution to OC release from these lake sediments. The range of the investigated boreal lakes reflects the high variability in the size of the sediment Fe–OC pool (0–1920 mol g-1) and CBD-extractable Fe (123–4050 mol g-1), which was not mirrored in the extent of reductive dissolution of Fe (18.9–84.6 mol g-1) and OC (1080–1700 mol g-1) during anoxia, suggesting that Fe-bound OC may play a minor role for sediment OC release in boreal lakes. However, studies of redox-related OC cycling in boreal lake sediments should consider that the amount of Fe–OC can be high in some lakes.

9505. 题目: Adsorption-desorption and degradation of insecticides clothianidin and thiamethoxam in agricultural soils
文章编号: N18053107
期刊: Chemosphere
作者: Yang Li, Peidong Su, Yadong Li, Kejun Wen, Guihong Bi, Michael Cox
更新时间: 2018-05-31
摘要: Studied were the adsorption-desorption and degradation of two widely used neonicotinoid insecticides clothianidin and thiamethoxam in three different agricultural soils in the state of Mississippi. The adsorptions of both the neonicotinoids fit a linear isotherm model. In different soils at different depths with different moisture contents, the adsorption distribution coefficients of clothianidin and thiamethoxam were found to be 0.62 to 1.94 and 0.59–2.03 L kg-1, respectively. These distribution coefficients showed strong positive correlations with organic carbon content and pH of the soils. The desorptions of clothianidin and thiamethoxam also followed a linear isotherm, but were irreversible in respect to their adsorption isotherms. The desorption distribution coefficients ranged from 0.14 to 0.62 L kg-1, increased with the decrease of organic carbon content. The degradations of clothianidin and thiamethoxam in the soils were found to be slow with half-lives ranged from 90 to 280 and 65 to 170 d for clothianidin and thiamethoxam respectively. The degradation rates increased with the increase of the organic carbon content in the soils. The moisture content in the soils had a positive effect on the degradation rates. The Groundwater Ubiquity Scores calculated from the adsorption distribution coefficient, organic content, and half-life suggest that clothianidin and thiamethoxam have moderate to high potential to leach to groundwater.

9506. 题目: Bioindication of human-induced soil degradation in enclosed karst depressions (dolines) using Ellenberg indicator values (Classical Karst, Slovenia)
文章编号: N18053106
期刊: Science of The Total Environment
作者: Mateja Breg Valjavec, Matija Zorn, Andra? ?arni
更新时间: 2018-05-31
摘要: One of the frequently used bioindication methods is Ellenberg indicator values (EIVs), which are commonly applied in Central Europe as bioindicators of ecological characteristics. However, very few studies have tested EIVs as a bioindication of human-induced soil degradation. We tested the ability of EIVs to distinguish between localities of degraded karst depressions (dolines) and localities of semi-natural (agricultural) soils in preserved dolines on the Kras Plateau (Classical Karst, SW Slovenia). We compared the results of bioindications of soil nutrient content (N), soil reaction (R) and soil moisture (M) with measured soil parameters. Low values of organic carbon, a slightly alkaline soil reaction and low organic sulphur content are chemical indicators of soil degradation in dolines, in comparison with preserved reference dolines (high organic carbon, slightly acid reaction, higher S). EIV reaction is the most reliable plant indicator value that can distinguish between degraded and non-degraded soil plots. According to a regression tree, sulphur (S) and C/N are the most important factors for division on the basis of EIV reaction. By applying the EIV reaction of diagnostic plant species, we significantly improved bioindication of soil degradation, although in the case of EIV nutrients, bioindication was not improved.
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9507. 题目: Direct oxygen uptake from air by novel glycogen accumulating organism dominated biofilm minimizes excess sludge production
文章编号: N18053105
期刊: Science of The Total Environment
作者: Md Iqbal Hossain, Andrea Paparini, Ralf Cord-Ruwisch
更新时间: 2018-05-31
摘要: The cost associated with treatment and disposal of excess sludge produced is one of the greatest operational expenses in wastewater treatment plants. In this study, we quantify and explain greatly reduced excess sludge production in the novel glycogen accumulating organism (GAO) dominated drained biofilm system previously shown to be capable of extremely energy efficient removal of organic carbon (biological oxygen demand or BOD) from wastewater. The average excess sludge production rate was 0.05 g VSS g-1 BOD (acetate) removed, which is about 9-times lower than that of comparative studies using the same acetate based synthetic wastewater. The substantially lower sludge yield was attributed to a number of features such as the high oxygen consumption facilitated by direct oxygen uptake from air, high biomass content (21.41 g VSS L-1 of reactor), the predominance of the GAO (Candidatus competibacter) with a low growth yield and the overwhelming presence of the predatory protozoa (Tetramitus) in the biofilm. Overall, the combination of low-energy requirement for air supply (no compressed air supply) and the low excess sludge production rate, could make this novel “GAO drained biofilm” process one of the most economical ways of biological organic carbon removal from wastewater.
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9508. 题目: Facile low-temperature one-step synthesis of pomelo peel biochar under air atmosphere and its adsorption behaviors for Ag(I) and Pb(II)
文章编号: N18053104
期刊: Science of The Total Environment
作者: Tuo Zhao, Ying Yao, Danrong Li, Feng Wu, Cunzhong Zhang, Bin Gao
更新时间: 2018-05-31
摘要: This study prepared a novel low-cost surface functionalized carbon adsorbent (PPC) from biomass waste (pomelo peel) through a facile low-temperature (250 °C) one-step method under regular air atmosphere. The adsorption performance and mechanism of the carbon material for Ag(I) and Pb(II) were investigated by a range of sorption experiments and characterizations including SEM, EDX, XRD and FTIR. Sorption experimental results suggested that PPC had high adsorption capacities of 137.4 and 88.7 mg/g for Ag(I) and Pb(II), respectively, with adsorbent dosage of 2 g/L at unadjusted solution pH and room temperature (23 ± 1 °C). The characterization results indicated high-efficiency removal of the heavy metals by PPC was attributed to the strong chemical adsorption involving that Ag(I) ions were reduced as metallic Ag particles by oxygenic functional groups and Pb(II) ions were precipitated as Pb5(PO4)3OH crystals by phosphorous functional groups on the carbon surfaces. This study provides the possibility of synthesis high-efficient adsorbent using economic and environmental-friendly approach with low energy consumption.
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9509. 题目: Monocarboxylic and dicarboxylic acids over oceans from the East China Sea to the Arctic Ocean: Roles of ocean emissions, continental input and secondary formation
文章编号: N18053103
期刊: Science of The Total Environment
作者: Qihou Hu, Zhouqing Xie, Xinming Wang, Hui Kang, Yuqing Zhang, Xiang Ding, Pengfei Zhang
更新时间: 2018-05-31
摘要: Organic acids are major components in marine organic aerosols. Many studies on the occurrence, sources and sinks of organic acids over oceans in the low and middle latitudes have been conducted. However, the understanding of relative contributions of specific sources to organic acids over oceans, especially in the high latitudes, is still inadequate. This study measured organic acids, including C14:0 – C32:0 saturated monocarboxylic acids (MCAs), C16:1, C18:1 and C18:2 unsaturated MCAs, and di-C4 – di-C10 dicarboxylic acids (DCAs), in the marine boundary layer from the East China Sea to the Arctic Ocean during the 3rd Chinese Arctic Research Expedition (CHINARE 08). The average concentrations were 18 ± 16 ng/m3 and 11 ± 5.4 ng/m3 for ΣMCA and ΣDCA, respectively. The levels of saturated MCAs were much higher than those of unsaturated DCAs, with peaks at C16:0, C18:0 and C14:0. DCAs peaked at di-C4, followed by di-C9 and di-C8. Concentrations of MCAs and DCAs generally decreased with increasing latitudes. Sources of MCAs and DCAs were further investigated using principal component analysis with a multiple linear regression (PCA-MLR) model. Overall, carboxylic acids originated from ocean emissions, continental input (including biomass burning, anthropogenic emissions and terrestrial plant emissions), and secondary formation. All the five sources contributed to MCAs with ocean emissions as the predominant source (48%), followed by biomass burning (20%). In contrast, only 3 sources (i.e., secondary formation (50%), anthropogenic emissions (41%) and biomass burning (9%)) contributed to DCAs. Furthermore, the sources varied with regions. Over the Arctic Ocean, only secondary formation and anthropogenic emissions contributed to MCAs and DCAs.
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9510. 题目: Retention and characteristics of microplastics in natural zooplankton taxa from the East China Sea
文章编号: N18053102
期刊: Science of The Total Environment
作者: Xiaoxia Sun, Tao Liu, Mingliang Zhu, Junhua Liang, Yongfang Zhao, Bo Zhang
更新时间: 2018-05-31
摘要: The ubiquitous presence and persistence of microplastics (MPs) in aquatic environments have become of particular concern in recent years. Biological interactions are among the key processes that affect the impact and fate of MPs in the oceans. Zooplankton is one of the most sensitive taxa because their prey is approximately the same size as MPs. However, the status of MPs in zooplankton within natural marine environments remains largely unknown. By focusing on zooplankton in the East China Sea, the characteristics, bioaccumulated concentration, and retention of MPs for 10 zooplankton groups were systematically studied. Three types of MPs were found in zooplankton: fibres, pellets, and fragments. The fibres (54.6%) were more common than the other two types. The average lengths of the fibres, pellets, and fragments were 295.2 ± 348.6 μm, 20.3 ± 11.0 μm, and 82.4 ± 80.5 μm, respectively. Nineteen polymers were detected in the zooplankton via the Thermo Scientific Nicolet iN10 Infrared Microscope. Polymerized oxidized organic material and polyester were dominant, accounting for 35.9% and 25.6% of the polymers, respectively. The bioaccumulated concentration of MPs in the 10 zooplankton taxa varied from 0.13 pieces/zooplankton for Copepoda to 0.35 pieces/zooplankton for Pteropoda. The bioaccumulated concentration was negatively correlated with the abundance of zooplankton, showing a significant biological dilution effect. The bioaccumulated concentration was also influenced by the feeding mode of zooplankton, showing a trend of omnivorous > carnivorous > herbivorous. High retention of MPs was found in the zooplankton community of the East China Sea, achieving 19.7 ± 22.4 pieces/m3. This is much higher than the MP retention in zooplankton from other reported sea areas. By revealing the characteristics and retention of MPs in the natural zooplankton taxa from the East China Sea, this research identified the influence that MPs have on zooplankton in a typical coastal environment. This information can be utilized for subsequent controlled experiments and risk assessments.
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9511. 题目: Using fluorescence-parallel factor analysis for assessing disinfection by-product formation and natural organic matter removal efficiency in secondary treated synthetic drinking waters
文章编号: N18053101
期刊: Science of The Total Environment
作者: Kalinda Watson, Maria José Farré, Frederic D.L. Leusch, Nicole Knight
更新时间: 2018-05-31
摘要: Parallel factor (PARAFAC) analysis of fluorescence excitation-emission matrices (EEMs) was used to investigate the organic matter and DBP formation characteristics of untreated, primary treated (enhanced coagulation; EC) and secondary treated synthetic waters prepared using a Suwannee River natural organic matter (SR-NOM) isolate. The organic matter was characterised by four different fluorescence components; two humic acid-like (C1 and C2) and two protein-like (C3 and C4). Secondary treatment methods tested, following EC treatment, were; powdered activated carbon (PAC), granular activated carbon (GAC), 0.1% silver-impregnated activated carbon (SIAC), and MIEX resin. Secondary treatments were more effective at removing natural organic matter (NOM) and fluorescent DBP-precursor components than EC alone. The formation of a suite of 17 DBPs including chlorinated, brominated and iodinated trihalomethanes (THMs), dihaloacetonitriles (DHANs), chloropropanones (CPs), chloral hydrate (CH) and trichloronitromethane (TCNM) was determined after chlorinating water sampled before and after each treatment step. Regression analysis was used to investigate the relationship between peak component fluorescence intensity (FMAX), DBP concentration and speciation, and more commonly used aggregate parameters such as DOC, UV254 and SUVA254. PARAFAC component 1 (C1) was in general a better predictor of DBP formation than other aggregate parameters, and was well correlated (R ≥ 0.80) with all detected DBPs except dibromochloromethane (DBCM) and dibromoacetonitrile (DBAN). These results indicate that the fluorescence-PARAFAC approach could provide a robust analytical tool for predicting DBP formation, and for evaluating the removal of NOM fractions relevant to DBP formation during water treatment.
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9512. 题目: Characteristics and compound-specific carbon isotope compositions of sedimentary lipids in high arsenic aquifers in the Hetao basin, Inner Mongolia
文章编号: N18052929
期刊: Environmental Pollution
作者: Ruoyu Mao, Huaming Guo, Wei Xiu, Yuance Yang, Xianyu Huang, Yinzhu Zhou, Xiaomeng Li, Jianyi Jin
更新时间: 2018-05-29
摘要: Organic matter, as an electron donor, plays a vital role in As mobilization mediated by microorganisms during reductive dissolution of Fe/Mn oxides in shallow aquifers. However, the specific types and sources of organic matter involved in biogeochemical processes accelerating As mobilization are still controversial. Both sediment and groundwater samples were collected at different depths from aquifers of the Hetao Basin, a typical inland basin hosting high As groundwater. Sedimentary lipids and their compound-specific carbon isotope ratios were analyzed to evaluate characteristics and sources of organic matter. Results show that sedimentary As were well correlated with Fe and Mn oxides, suggesting that As exist as Fe/Mn oxide bound forms. Groundwater As far exceeded the drinking water guide value of 10 μg/L. Moreover, As concentrations in shallow groundwater were relatively higher. Lipids in clay were mainly originated from terrestrial higher plants, while that in fine sand samples were derived from terrestrial higher plants, microorganism and petroleum. Shallow fine sand samples were also characterized by evident in-situ biodegradation. Compound-specific carbon isotope compositions of sedimentary lipids showed that short-chain n-alkanes and n-alkanoic acids had more positive δ13C values compared to long-chain compounds, especially in shallow fine sand samples. δ13CTOC were also low in shallow fine sand samples. These results jointly indicate that these lipids in shallow fine sand samples acted as carbon source for indigenous microorganism and the short-chain components were particularly more vulnerable to biodegradation, which may contribute to high As concentrations in shallow groundwater. The new findings provide the first evidence that short chain length n-alkyl compounds afforded a source of potential electron donors for microbially mediated As mobilization process in the shallow aquifers.
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9513. 题目: Comparing macroinvertebrate assemblages at organic-contaminated river sites with different zinc concentrations: Metal-sensitive taxa may already be absent
文章编号: N18052928
期刊: Environmental Pollution
作者: Yuichi Iwasaki, Takashi Kagaya, Hiroyuki Matsuda
更新时间: 2018-05-29
摘要: We investigated responses of macroinvertebrates to different zinc concentrations in urban rivers contaminated with organic matter in a regional-scale monitoring survey and a smaller-scale field study. The present study was designed to test our prediction that total zinc concentrations of 60 μg/L (twice the Japanese environmental quality standard) do not lead to significant reductions in richness or abundance of macroinvertebrates in organic-contaminated rivers (biochemical oxygen demand of >3 mg/L). At the organic-contaminated sites in both surveys, very few species were present, and metal-sensitive heptageniid and ephemerellid mayflies were generally absent. In the regional-scale study, total zinc concentrations of up to 70 μg/L resulted in little reduction in macroinvertebrate richness. In the local-scale study, macroinvertebrate richness and abundance were not greatly reduced at the polluted downstream site with a total zinc concentration of 48 μg/L. Results from both surveys support our prediction. Therefore, an important implication of this study is that macroinvertebrate taxa that are susceptible to metal pollution should be sparse or absent in organic-contaminated rivers, so the impacts of metals such as zinc may be limited owing to the species-poor communities. Further research is required to evaluate the importance of reduced zinc bioavailability associated with increased organic matter and water hardness to the species-poor communities in organic-contaminated rivers.
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9514. 题目: Interactions between iron mineral-humic complexes and hexavalent chromium and the corresponding bio-effects
文章编号: N18052927
期刊: Environmental Pollution
作者: Zhiyong Zheng, Yue Zheng, Xiaochun Tian, Zhaohui Yang, Yanxia Jiang, Feng Zhao
更新时间: 2018-05-29
摘要: The interfacial behaviors of chromium are fundamental for understanding the environmental effects of chromium in contaminated environments. However, complex surfaces can cause chromium to exhibit a variety of behaviors, especially when humic substances are considered. This work illustrated the role of humics (humic acid and fulvic acid) during the adsorption of Cr(VI) onto iron minerals (magnetite and hematite). The interfacial behaviors were investigated through their adsorption kinetics, adsorption isotherms, and thermodynamics. Then, the microbial diversity was monitored to reflect the bio-effects of Cr(VI) adsorbed onto four iron oxide-humic complexes. The differences in the adsorption capacities and mechanisms of Cr(VI) on the surfaces of the iron mineral-humic complexes were observed. Humics obviously decreased the adsorption capacities of Cr(VI) on the hematite complexes and relieved the decline in the microbial diversity; meanwhile, humics imposed relatively insignificant changes to the Cr(VI) adsorption capacity onto the magnetite complexes. Thus, the corresponding microbial diversity might be mainly affected by released micelles formed by Cr(VI) and humics. These results illustrate the complexities of the interfacial behaviors of Cr(VI) on the surfaces of iron mineral-humic complexes and broaden the current understanding of chromium migration and transportation.
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9515. 题目: Exogenous acyl-homoserine lactones adjust community structures of bacteria and methanogens to ameliorate the performance of anaerobic granular sludge
文章编号: N18052926
期刊: Journal of Hazardous Materials
作者: Longyi Lv, Weiguang Li, Zejia Zheng, Donghui Li, Ning Zhang
更新时间: 2018-05-29
摘要: Quorum sensing (QS) signalling has been extensively studied in single species populations, activated sludge, biofilm and aerobic granular sludge. However, ecological roles of QS in anaerobic granular sludge, particularly in the content of the relationship between QS signalling and microbial community composition and function, have been rarely reported. Herein, five acyl-homoserine lactones (AHLs) molecules were added in the anaerobic granular sludge system for treating traditional Chinese medicine (TCM) wastewater respectively. The results indicated that the introduction of specific AHLs could enhance the abilities of organic matters removal and methanation in anaerobic granular sludge, and meanwhile, exogenous AHLs played an important role to regulate the concentration of EPS. Sequencing analysis indicated that microbial community structures of bacteria and methanogens changed to varying degrees by adding AHLs. This study suggested that exogenous AHLs could play a role in mediating microbial community structure, thereby enhancing the performance of anaerobic granular sludge. The regulatory mechanism of AHLs on community structure was discussed, and a speculative action model was established. Exogenous regulation by selective enhancement of AHLs-mediated QS in anaerobic granular sludge provided an innovative and attractive strategy for strengthening wastewater treatments.

9516. 题目: Exploring the fate and oxidation behaviors of different organic constituents in landfill leachate upon Fenton oxidation processes using EEM-PARAFAC and 2D-COS-FTIR
文章编号: N18052925
期刊: Journal of Hazardous Materials
作者: Bilal Aftab, Hyun-Sang Shin, Jin Hur
更新时间: 2018-05-29
摘要: In this work, the changes of different organic constituents in landfill leachate were tracked in Fenton oxidation processes with different operation parameters including H2O2 doses, pH, and the ratios of [H2O2]/[Fe] via fluorescence excitation emission matrix – parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation spectroscopy (2D-COS). One tryptophan-like (C1), one fulvic-like (C2), and one humic-like (C3) components were identified in the leachates. The removal behaviors of the individual fluorescent components were dependent upon the operation conditions, suggesting the existence of unique characteristics with respect to the responses to the oxidation mechanisms, which were likely altered by different operation conditions. For all tested conditions, a greater extent of removal was consistently found for C3 versus C1 and C2 except for the relatively high pH ranges (>6.0), in which C2 presented the highest removal rates. 2D-COS combined with synchronous fluorescence spectra exhibited the preferential oxidation sequence in the order of C3 > C1 > C2 with higher H2O2 doses. 2D-COS coupled with Fourier transform infrared (2D-COS-FTIR) showed that aromatic functional groups were initially oxidized, followed by the removal of carboxylic groups and the formation of inorganic functional groups and aldehyde or ketonic groups. Hetero 2D-COS maps further revealed the close association between the aromatic groups and C3, and between the carboxylic groups and C1. This study utilizing 2D-COS provided new insights into the dynamic behavior of heterogeneous landfill leachate in Fenton oxidation processes under varying operation conditions.
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9517. 题目: Influence of natural organic matter on horseradish peroxidase-mediated removal of 17α-ethinylestradiol: Role of molecular weight
文章编号: N18052924
期刊: Journal of Hazardous Materials
作者: Yun Yang, Jianhua Li, Huanhuan Shi, Li Zhai, Xing Wang, Shixiang Gao
更新时间: 2018-05-29
摘要: Ubiquitous natural organic matter (NOM) plays a crucial role in the peroxidase-mediated transformation of phenolic pollutants in aquatic environment. As a poorly defined polydispersed mixture of assorted organic substances with wide molecular weight (MW) distribution, NOM has far prevented researchers from finding out the primarily responsible components for the specific effect. In this work, MW fractionated NOMs (Mf-NOMs) were used to investigate their roles on horseradish peroxidase (HRP)-mediated transformation of 17α-ethinylestradiol (EE2). The removal rate of EE2 was restrained in the presence of pristine or Mf-NOMs, and the inhibitory mechanism was MW-dependent. Low Mf-NOMs restrained the enzymatic reaction by acting as competitive substrates, while high Mf-NOMs retained freely dissolved EE2 which reduced its availability for enzymatic reaction. The contribution of these two processes to the inhibition induced by pristine NOM was further quantified and found to be relevant to the reaction conditions, especially EE2 concentration. The findings of this work reveal more complex influences of NOM on the enzymatic reaction than ever demonstrated, which aids in understanding the fate of EE2 and other congener contaminants in natural and municipal water.
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9518. 题目: Raw hematite based Fe(III) bio-reduction process for humified landfill leachate treatment
文章编号: N18052923
期刊: Journal of Hazardous Materials
作者: Rui Li, Yu Jiang, Beidou Xi, Mingxiao Li, Xiaoguang Meng, Chuanping Feng, Xuhui Mao, Hongliang Liu, Yonghai Jiang
更新时间: 2018-05-29
摘要: Microorganisms from paddy soils and raw hematite are used for enhancing natural Fe(III) bio-reduction, in order to remove macromolecular organic pollutants from humified landfill leachate. Based on batch experiments, 60% of refractory organics can be adsorbed by hematite in 12 days. In the presence of Fe(III)-reducing bacteria, 489.60 ± 0.14 mg L-1 of dissolved organic matters can be degraded to 51.90 ± 3.96 mg L-1 within 50 days; twelve types of semi volatile organic compounds can be degraded; hereby, the reaction follows a first-order kinetics. Crystalline Fe(III) is transformed into the amorphous form and reduced to Fe(II), hydroquinone functional groups in the humic acid (HA) are transformed to quinone ones, and the formation of HA-hematite ligands is promoted. Comparing with most of the studies about electron shuttling of HA, the transformation of quinone in the HA to hydroquinone could not be observed in the present bio-system. Based on column evaluations, more than 93% of chemical oxygen demand (influent concentration of 658 ± 19 mg L-1) could be removed microbially under flow conditions, when the hydraulic retention time was 45 h. Raw hematite-based Fe(III) bio-reduction has a promising potential for the removal of humic and benzene series in humified landfill leachate.
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9519. 题目: Functional lignocellulosic material for the remediation of copper(II) ions from water: Towards the design of a wood filter
文章编号: N18052922
期刊: Journal of Hazardous Materials
作者: Selin Vitas, Tobias Keplinger, Nico Reichholf, Renato Figi, Etienne Cabane
更新时间: 2018-05-29
摘要: In this study, the chemical modification of bulk beech wood is described along with its utilization as biosorbent for the remediation of copper from water. The material was prepared by esterification using anhydrides, and reaction conditions were optimized to propose a greener process, in particular by reducing the amount of solvent. This modification yields a lignocellulosic material whose native structure is preserved, with an increased amount of carboxylic groups (up to 3 mmol/g). We demonstrate that the material can remove up to 95% of copper from low concentration solutions (100– 500 ppm). The adsorption efficiency decreases with concentrated copper solutions, and we show that a limited number of -COOH groups participate in copper binding (ca. 0.1 Cu/-COOH). This result suggests a limited accessibility of -COOH groups in the wood scaffold. This was demonstrated by the characterization of -COOH and copper distributions inside wood. Raman and EDX imaging confirmed that most –COOH groups are located inside the wood cell walls, thereby limiting interactions with copper. According to this study, critical limitations of bulk wood as a biosorbent were identified, and the results will be used to improve the material and design an efficient wood filter for heavy metal remediation.
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9520. 题目: Binding of Cd by ferrihydrite organo-mineral composites: Implications for Cd mobility and fate in natural and contaminated environments
文章编号: N18052921
期刊: Chemosphere
作者: Huihui Du, Caroline L. Peacock, Wenli Chen, Qiaoyun Huang
更新时间: 2018-05-29
摘要: Adsorption and coprecipitation of organic matter with iron (hydr)oxides can alter iron (hydr)oxide surface properties and their reactivity towards nutrient elements and heavy metals. Organo-mineral composites were synthesized using humic acid (HA) and iron oxide, during coprecipitation with ferrihydrite (Fh) and adsorption to pre-formed Fh with two C loadings. The Fh-HA coprecipitated composites have a higher C content and smaller surface area compared to the equivalent adsorbed composites. NanoSIMS shows there is a high degree of spatial correlation between Fe and C for both composites, but C distribution is more uniform in the coprecipitated composites. The C 1s NEXAFS reveals a similar C composition between the Fh-HA coprecipitated and adsorbed composites. However composites at high carbon loading are more enriched in aromatic C, likely due to preferential binding of carboxyl functional groups on aromatic rings in the HA. The amount of Cd sorbed is independent of the composite type, either coprecipitated or adsorbed, but is a function of the C loading. Composites with low C loading show Cd sorption that is almost identical to pure Fh, while composites with high C loading show Cd sorption that is intermediate between pure Fh and pure HA, with sorption significantly enhanced over pure Fh at pH < 6.5. A bidentate edge-sharing binding was identified for Cd on pure Fh and Cd-carboxyl binding on pure HA. These findings have significant implications not only for the sequestration of Cd in contaminated environments but also the coupled biogeochemical cycling of Cd, Fe and C in the critical zone.
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