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12841. 题目: Photochemical reaction of tricresyl phosphate (TCP) in aqueous solution: Influencing factors and photolysis products
文章编号: N19100607
期刊: Chemosphere
作者: Shibin Sun, Jingqiu Jiang, Hongxia Zhao, Huihui Wan, Baocheng Qu
更新时间: 2019-10-06
摘要: Organophosphate triesters (OPEs) have caused great concern as a class of emerging environmental contaminants due to their widespread use and their toxicity to organisms. However, the phototransformation behavior of OPE is still not fully understood, which is important for understanding their environmental fate. In the present study, the photodegradation of tricresyl phosphate (TCP), one of the most widely detected OPEs in aqueous environments, was investigated including the direct photolysis and in the presence of several natural water factors, NO2, Fe3+ and humic acid. The degradation process followed the pseudo-first-order kinetics, with rate constant increasing slightly with increasing initial TCP concentration. The presence of NO2 and Fe3+ was observed to promote the photochemical loss of TCP, while humic acid played a negative role on TCP transformation. Electron spin resonance (EPR) analysis showed that carbon-centered radical was produced in the photolysis process of TCP, and hydroxyl radical contributed to the promotion of rate constant for Fe3+ and NO2. Four photolysis products were tentatively identified by HPLC-LTQ-Orbitrap MS analysis, and the possible degradation pathways of TCP were proposed. These findings provide a meaningful reference for the fate and transformation of OPEs in natural water.
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12842. 题目: Degradation mechanism, intermediates and toxicology assessment of tris-(2-chloroisopropyl) phosphate using ultraviolet activated hydrogen peroxide
文章编号: N19100606
期刊: Chemosphere
作者: Xiaolong Yu, Hua Yin, Hui Peng, Guining Lu, Zehua Liu, Huanyong Li, Zhi Dang
更新时间: 2019-10-06
摘要: Organophosphate flame retardants (OPFRs), one kind of emerging flame retardants, have received prevalent attention owing to their ubiquity in aquatic matrices and their characteristics of being refractory to biodegradation. In current research, the degradation mechanism of tris-(2-chloroisopropyl) phosphate (TCPP), one of OPFRs, and its toxicological evaluation using UV-driven hydroxyl radical oxidation were investigated. A pseudo-first order reaction was fitted with an apparent rate constant (Kobs) of 0.1328 min−1 on transformation of TCPP in the case of CH2O2 0.1 mM, pH 6.6–7.1 and 4.7 mW cm−2 UV irradiation. High resolution mass spectroscopy analyses identified nine degradation products (eg., C6H13Cl2O4P (m/z 251.0002), C9H17Cl2O5P (m/z 307.0266), C9H17Cl2O6P (m/z 323.0217), C9H18Cl3O5P (m/z 343.0033)) during transformation of TCPP. The removal efficiency dropped by inhibitory effect of natural organic matters and anions, implying that the complete mineralization of TCPP may be difficult in actual water treatment process. The toxicity assessment has shown an decrease in reactive oxygen species (ROS) and apoptosis, membrane potential (MP) elevation of Escherichia coli, and biological molecular function revision (eg., metabolism and DNA biosynthesis), indicating that toxicity of degradation products were conspicuously decreased in comparison with intact TCPP. To sum up, effective detoxification of TCPP can be realized by a UV driving radical-based oxidation, which will provide an alternative safe treatment method to control TCPP in water matrix.

12843. 题目: Comparison between ferrihydrite adsorption and full-scale advanced drinking water treatment processes for controlling bacterial regrowth potential
文章编号: N19100605
期刊: Chemosphere
作者: Yu Yang, Jenyuk Lohwacharin, Satoshi Takizawa, Li-an Hou
更新时间: 2019-10-06
摘要: Bacterial regrowth in drinking water systems is a threat to public health. In this study, ferrihydrite (Fh) adsorption was compared with advanced drinking water treatment processes (ADWTP) during one and a half years of sampling to test the reduction in assimilable organic carbon (AOC) and bacterial regrowth potential (BRP). Dissolved organic matter (DOM) was removed by Fh through ligand exchange and electrostatic interaction. The DOM removal was higher below pH 6 due to protonation of Fh surfaces. The ADWTP exhibited higher removal rates of DOM than Fh and lower phosphate removal rates than Fh. Excitation-emission matrix (EEM) and size exclusion chromatography (SEC) revealed that Fh removed aromatic DOM larger than 1000 Da, while the biological activated carbon (BAC) of ADWTP could remove DOM smaller than 1000 Da. These differences of organic compositions resulted in the lowest AOC of BAC treated water, and the lowest BRP of Fh-treated water, indicating that it was the most biostable water. Phosphate addition experiments illustrated that phosphorus was the primary rate limiting nutrient, indicating that the higher phosphate removal of Fh made it possible to produce waters with lower BRP than ADWTP. Therefore, BRP is considered to be a better indicator of bacterial regrowth than AOC when phosphorus is a rate-limiting nutrient, as is the case with the Fh treatment.

12844. 题目: The innovative application of organosolv lignin for nanomaterial modification to boost its heavy metal detoxification performance in the aquatic environment
文章编号: N19100604
期刊: Chemical Engineering Journal
作者: Zexu Chi, Lan Hao, Heng Dong, Han Yu, Houke Liu, Hongbing Yu
更新时间: 2019-10-06
摘要: Lignin is one of the most abundant organic materials in the world, and its valuable utilization has become an emerging area of research due to its excellent physical and chemical properties and environmentally friendly characteristics. Nanomaterials hold promise in many fields, however, aggregation and deactivation in the aquatic environment have hindered its development and practical application. Here, the application of organosolv lignin (Org-lignin) for the modification of nanoscale zero-valent iron (nZVI) to boost its hexavalent chromium (Cr(VI)) detoxification performance in the aquatic environment was demonstrated for the first time. Org-lignin was served as stabilizers and Al-bent was selected as carriers to synthesize Org-lignin anchored and aluminum pillared bentonite (Al-bent) supported nZVI (L-nZVI@Ab). Thanks to the dispersing and anchoring effect of Org-lignin, L-nZVI@Ab offered the advantage of aggregation-resistant. Additionally, the synergistic effect of Org-lignin and Al-bent could alleviate the deposition of redox by-products on the surface of nZVI, thereby reducing its deactivation and improving its reusability. These gave L-nZVI@Ab more efficient removal of Cr (VI) than bare nZVI and Al-bent supported nZVI (B-nZVI) in aqueous solution, and the optimal reductive removal amount of Cr(VI) by L-nZVI@Ab was 46.2 mg g−1. Batch experiments exhibited that the kinetics of Cr(VI) removal by L-nZVI@Ab under various conditions conformed to a pseudo-first-order rate expression. Our work notably expanded possibilities for the use of lignin in the field of nanomaterial modification.
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12845. 题目: Fouling control in ultrafiltration of secondary effluent using polyaniline/TiO2 adsorption and subsequent treatment of desorption eluate using electrochemical oxidation
文章编号: N19100603
期刊: Chemical Engineering Journal
作者: Xiaoliang Li, Gang Tang, Dou Zhang, Linjie Wu, Sijia Lu, Yaozhong Zhang, Xin Cao, Wen Cheng, Jiangtao Feng, Wei Yan, Baozhu Pan, Li Li, Zhanbin Li, Xing Zheng
更新时间: 2019-10-06
摘要: Performance of three adsorbents, polyaniline-modified TiO2 (PANI/TiO2), Dow resin IRA(a) and Dow resin IRA(b), in removing organics from secondary effluent (SE) was evaluated, and the objective of this study is to deliver a treatment loop including membrane fouling control using adsorption and treatment of correspondingly formed desorption eluate using electrochemical oxidation, so that the contaminants could be effectively handled within a wastewater treatment plant. Results show that PANI/TiO2 is a promising adsorbent in the removal of effluent organic matter (>55%) and its regeneration was superior to the two others. Specifically, PANI/TiO2 could remove over 70% of the fraction of biopolymers from the SE and therefore alleviated subsequent membrane fouling to a large extent, while the other two presented less antifouling effect due to limited removal of the major foulants, though they both showed comparable effect as PANI/TiO2 in the removal of other organic fractions. BOD5/COD of the concentrated desorption eluate was gradually increasing along with the extension of the electrochemical oxidation. It reached >0.4 after 4.5 h of treatment, which is of suitable biodegradability for recycling to the influent of the wastewater treatment plant. The improvement on BOD5/COD was due to the mineralization of effluent organic matter and simultaneous minifying of their molecular size. Moreover, the operation cost of the treatment loop was estimated at about 0.12–0.15 USD/m3 for delivering effect fouling control and significant improvement on effluent quality.
图文摘要:

12846. 题目: Enhancement effect among a UV, persulfate, and copper (UV/PS/Cu2+) system on the degradation of nonoxidizing biocide: The kinetics, radical species, and degradation pathway
文章编号: N19100602
期刊: Chemical Engineering Journal
作者: Min-Yong Lee, Wen-Long Wang, Ye Du, Hong-Ying Hu, Nan Huang, Zi-Bin Xu, Qian-Yuan Wu, Bei Ye
更新时间: 2019-10-06
摘要: Reverse osmosis concentrate (ROC) generally contains highly toxic and biorefractory organic pollutants. In this study, various oxidation systems, including UV, persulfate (PS)/Cu2+, UV/PS, and UV/PS/Cu2+, were evaluated for the degradation of nonoxidizing biocides, which are commonly used in reverse osmosis systems for preventing biofouling. The results showed that UV/PS/Cu2+ had an enhancement effect among UV, PS, and Cu2+. Compared with UV/PS, the degradation efficiency of UV/PS/Cu2+ increased 4.4%–22.2% for dodecyl trimethyl ammonium chloride (DTAC) and 19%–37.6% for dodecyl dimethyl benzyl ammonium chloride (DDBAC). The kobs of DTAC and DDBAC by UV/PS/Cu2+ were approximately 1.5–2 times higher than those of the UV/PS system, which were examined to be 0.569 and 0.602 min−1, respectively. The contributions of SO4, HO, and other way on the degradation of DTAC and DDBAC in the UV/PS/Cu2+ system were observed to be 77.0%, 1.0%, and 22.1% for DTAC and 55.3%, 1.0%, and 12.0% for DDBAC, respectively, at pH 7. The effect of humic acids (HAs) and natural organic matter (NOM) considerably impeded the degradation of DTAC (50 and 54%) and DDBAC (47 and 69%) when the concentration of HAs and NOM was 1 and 10 mg/L, respectively. The degradation of DTAC by various metals was enhanced in the order Cu2+ > Fe2+ > Mg2+ > Mn2+ at 0.1 mg/L, whereas that of DDBAC was Cu2+ > Mg2+ > Zn2+ > Fe2+ > Mn2+.
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12847. 题目: A metal organic framework-ultrafiltration hybrid system for removing selected pharmaceuticals and natural organic matter
文章编号: N19100601
期刊: Chemical Engineering Journal
作者: Sewoon Kim, Juan C. Muñoz-Senmache, Byung-Moon Jun, Chang Min Park, Am Jang, Miao Yu, Arturo J. Hernández-Maldonado, Yeomin Yoon
更新时间: 2019-10-06
摘要: In this study, we combined metal organic frameworks (MOFs) with ultrafiltration (UF) hybrid systems (MOF-UF) to treat selected pharmaceutically active compounds (PhACs), including ibuprofen and 17α-ethinyl estradiol, and natural organic matter (NOM) (humic acid and tannic acid; ratios of 10:0, 5:5, and 0:10). Due to the high tunable porosity of MOFs, these materials have strong potential for removing contaminants and reducing fouling in adsorbent-UF hybrid systems. The average retention rate of PhACs in MOF-UF (53.2%) was enhanced relative to the UF only (36.7%). The average retention rate of NOM in the MOF-UF (86.1%) was higher than that with UF only (75.7%). Also, the average normalized flux of NOM in the MOF-UF (0.79) was better than that with UF only (0.74). This is because the PhACs were effectively adsorbed on the MOF due to their strong porous characteristics. We compared MOF-UF and powdered activated carbon-UF (PAC-UF) systems in terms of retention rates and flux decline. The average retention rates for the MOF-UF were higher relative to PAC-UF, by 4.6% for PhACs and 6.9% for NOM. However, although the normalized flux in the MOF-UF was better than that in the PAC-UF, for both PhACs and NOM, severe flux decline for NOMs was seen for with the MOF-UF and PAC-UF. We evaluated the effects of NOM with respect to fouling by applying a resistance-in-series model and found that fouling was dominantly affected by the molecular sizes of the solutes in the solution.

12848. 题目: Heavy metal phytoavailability in a contaminated soil of northeastern Oklahoma as affected by biochar amendment
文章编号: N19100511
期刊: Environmental Science and Pollution Research
作者: João Arthur Antonangelo, Hailin Zhang
更新时间: 2019-10-05
摘要: High concentrations of heavy metals (HM) in soils have negative impacts on plants, human health, and the environmental quality. The purpose of this study was to evaluate the effects of biochars on the bioaccessibility of Zn, Pb, and Cd in a contaminated soil in the Tar Creek area of NE Oklahoma, as well as on the growth and uptake of these elements by perennial ryegrass (Lolium perenne). Biochars were produced from switchgrass (SGB) and poultry litter (PLB) feedstocks at 700 °C and applied to the soil at 0.0, 0.5, 1.0, 2.0, and 4.0% (w/w), with three replications. Regardless of the feedstock, both soil organic carbon (SOC or OC) and pH increased as the rates of biochars increased, which significantly decreased the HM bioaccessibility (p < 0.01). The Zn and Cd extracted by DTPA were highly correlated (p < 0.0001) with their concentration in ryegrass shoots and roots. Except for some significant positive correlations (p < 0.05), HM concentrations in ryegrass shoots and roots were not correlated with their biomass (p > 0.05). Both bioconcentration factor (BCF) and transfer factor decreased as the rates of biochars applied increased, especially for Pb and Cd (p < 0.01). Our results suggest it is beneficial to use biochars at Tar Creek as a soil amendment to reduce HM bioaccessibility and metal uptake by ryegrass.

12849. 题目: Roles of adding biochar and montmorillonite alone on reducing the bioavailability of heavy metals during chicken manure composting
文章编号: N19100510
期刊: Bioresource Technology
作者: Jingkun Hao, Zimin Wei, Dan Wei, Taha Ahmed Mohamed, Huimin Yu, Xinyu Xie, Longji Zhu, Yue Zhao
更新时间: 2019-10-05
摘要: The aim of this study was to explore the effects of adding biochar and montmorillonite alone on the correlations between bacteria and bioavailability of heavy metals (HM) during chicken manure composting. Three composting experiments were conducted, containing the without ameliorant, 10% biochar and 10% montmorillonite. The results showed that biochar and montmorillonite ameliorants significantly reduced the bioavailability of Cu by 90.3%, 81.2%, while that of Zn by 11.7%, 15.6%, respectively. Meanwhile, they also significantly changed bacterial community structure and enhanced the correlation between bacterial bands (i.e., 19, 24, 26 and 30) and HM fractions. This correlation was validated in network analysis. Structural equation models further confirmed that bacteria had a complete and effective pathway to influence the bioavailability of HM. In summary, this study suggested that biochar and montmorillonite additions were an effective regulation method to reduce the bioavailability of HM from composting system.
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12850. 题目: A green biochar/iron oxide composite for methylene blue removal
文章编号: N19100509
期刊: Journal of Hazardous Materials
作者: Ping Zhang, David O’Connor, Yinan Wang, Lin Jiang, Tianxiang Xia, Liuwei Wang, Daniel C.W. Tsang, Yong Sik Ok, Deyi Hou
更新时间: 2019-10-05
摘要: Adsorbents that effectively remove dye substances from industrial effluents are needed for the protection of human health and the natural environment. However, adsorbent manufacture is associated with secondary environmental impacts. In this study, a green biochar/iron oxide composite was produced using a facile approach involving banana peel extract and FeSO4. The modified biochar’s capacity to adsorb methylene blue (MB) was considerably enhanced (Langmuir Qmax of 862 mg/g for MB when C0 = 500 mg/L, pH = 6.1, T =313 K) compared to the unmodified banana peel biochar, and exhibited good performance for a wide range of pH values (pH 2.05–9.21). The Langmuir isotherm model and pseudo second-order kinetic model accurately describe the adsorption process. The material properties and corresponding adsorption mechanisms were investigated by various experimental techniques. Enhanced MB adsorption by the biochar/iron oxide composite is attributed to increased electronic attraction to MB molecules, as evidenced by XPS analysis. High adsorption capacity was retained after 5 regeneration cycles. This study suggests that biochar can be modified by a green synthesis approach to produce biochar/iron oxide composite with good MB removal capacity.
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12851. 题目: A long-term, high-latitude record of Eocene hydrological change in the Greenland region
文章编号: N19100508
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Gordon N. Inglis, Matthew J. Carmichael, Alex Farnsworth, Daniel J. Lunt, Richard D. Pancost
更新时间: 2019-10-05
摘要: A range of proxy approaches have been used to reconstruct short-term changes to Earth’s hydrological cycle during the early Eocene hyperthermals. However, little is known about the response of Earth’s hydrological and biogeochemical systems to long-term Cenozoic cooling, which began following the Early Eocene Climatic Optimum (53.3 – 49.4 million years ago; Ma). Here, we use the molecular distribution and isotopic composition of terrestrial biomarkers preserved in marine sediments of ODP Site 913, East Greenland, to develop a long-term record of high-latitude hydrological change between 50 and 34 Ma. There is a marked decline in the concentration of conifer-derived diterpenoids and angiosperm-derived triterpenoids during the Eocene. As the input of wind-blown conifer pollen remains stable during this interval, this implies that decreasing di- and triterpenoid concentrations reflect declining influence of fluvial inputs – and perhaps terrestrial runoff – throughout the Eocene. Branched GDGTs and bacterial-derived hopanes indicate an increased input of soil- and kerogen-derived organic matter, respectively, after 38 Ma. This coincides with evidence for ice rafted debris and suggests input of organic matter via glacial processes. This also implies some continental glaciation occurred on East Greenland in the middle-to-late Eocene. Leaf wax hydrogen isotopes extending throughout this section – the first such long-term record from the Paleogene - indicate that precipitation δ2H was persistently higher than that of modern coastal Greenland, consistent with warmer ocean source waters and enhanced poleward moisture transport. Non-intuitively, however, this effect appears to have been smallest during the warmest part of the record, and higher δ2H values occur in the middle Eocene. Although interpretation of these hydrogen isotope trends is unclear, they clearly indicate – alongside the changes in biomarker abundances – a perturbed hydrological cycle through the Eocene in coastal Greenland. More long-term records are required to ascertain if this represents regional or global hydrological reorganisation.

12852. 题目: Plant-plant competition influences temporal dynamism of soil microbial enzyme activity
文章编号: N19100507
期刊: Soil Biology and Biochemistry
作者: E.J. Schofield, R.W. Brooker, J.K. Rowntree, E.A.C. Price, F.Q. Brearley, E. Paterson
更新时间: 2019-10-05
摘要: Root-derived compounds can change rates of soil organic matter decomposition (rhizosphere priming effects) through microbial production of extracellular enzymes. Such soil priming can be affected by plant identity and soil nutrient status. However, the effect of plant-plant competition on the temporal dynamics of soil organic matter turnover processes is not well understood. This study used zymography to detect the spatial and temporal pattern of cellulase and leucine aminopeptidase activity, two enzyme classes involved in soil organic matter turnover. The effect of plant-plant competition on enzyme activity was examined using barley (Hordeum vulgare) plants grown in i) isolation, ii) intra- and iii) inter-cultivar competition. The enzyme activities of leucine aminopeptidase and cellulase were measured from portions of the root system at 18, 25 and 33 days after planting, both along the root axis and in the root associated area with detectable enzyme activity. The activities of cellulase and leucine aminopeptidase were both strongly associated with plant roots, and increased over time. An increase in the area of cellulase activity around roots was delayed when plants were in competition compared to in isolation. A similar response was found for leucine aminopeptidase activity, but only when in intra-cultivar competition, and not when in inter-cultivar competition. Therefore, plant-plant competition had a differential effect on enzyme classes, which was potentially mediated through root exudate composition. This study demonstrates the influence of plant-plant competition on soil microbial activity and provides a potential mechanism by which temporal dynamism in plant resource capture can be mediated.
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12853. 题目: Development of methods for extraction and analytical characterization of carbon-based nanomaterials (nanoplastics and carbon nanotubes) in biological and environmental matrices by asymmetrical flow field-flow fractionation
文章编号: N19100506
期刊: Environmental Pollution
作者: Fazel Abdolahpur Monikh, Nadine Grundschober, Stefan Romeijn, Daniel Arenas-Lago, Martina G. Vijver, Wim Jiskoot, Willie J.G.M. Peijnenburg
更新时间: 2019-10-05
摘要: Suitable methods and fit-for-purpose techniques are required to allow characterization of carbon-based nanomaterials (CB-NMs) in complex matrices. In this study, two methods were developed; a method for extraction and characterization of CB-NMs in biological media and a method for fractionation of natural organic matter (NOM) coated CB-NMs in environmental matrices. The former method was developed by extracting carbon nanotubes (CNTs: sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 600 nm) from eggshells and characterizing the extracted CB-NMs in terms of particle size distribution using asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS). The latter method was developed using AF4-MALS to fraction NOM-coated CNT (sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 300 nm) in a simulated natural surface water and provide information about the size distribution of the CB-NM-NOM complexes. The developed AF4-MALS method successfully fractioned the CB-NM-NOM complexes based on hydrodynamic size and provided the size distribution of the complexes. The NOM corona did not shift significantly the median size of the CB-NMs. It influenced however the size distribution of the nanoplastics and CNTs. The sample preparation method failed to extract the CNTs (recovery < 20%) from the matrices of the eggshells while being successful for extracting the nanoplastics (recoveries > 60%). The AF4-MALS fractogram showed that the extraction method did not significantly influence the size distribution of the nanoplastics of 60 and 200 nm size, whereas the peak of 600 nm nanoplastics shifted towards a smaller hydrodynamic size. In conclusion, the developed sample preparation method followed by the developed AF4-MALS method can be applied for extraction, separation and characterization of CB-NMs in biological and environmental matrices. Thus, the methods have a high potential to be methods of choice to investigate CB-NMs in future studies.
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12854. 题目: Promotional effect of Mn(II)/K2FeO4 applying onto Se(IV) removal
文章编号: N19100505
期刊: Journal of Hazardous Materials
作者: Zaitsev Viktor, Lu Wang, Jun Ma
更新时间: 2019-10-05
摘要: Promotional effect of Mn(II)/K2FeO4 [Fe(VI)] applying onto Se(IV) removal was determined for the first time, with description of reaction mechanisms. Four different combinations of water treatment agents [K2FeO4 alone, K2FeO4 with Al(III) ions, K2FeO4 with Fe(III) ions, and K2FeO4 with Mn(II) ions] were used for Se removal in spiked deionized water, and K2FeO4 in combination with Mn(II) ions showed great removal efficiency. Over 90% of Se(IV) (200 μg/L) was removed within 2 min by using 1 mg/L of K2FeO4 and 9 mg/L of Mn(II) ions (pH 7.0, 23 °C). XPS analysis identified that in the reaction process, Se(0) formed on the settlement. It was speculated that Se(IV) was oxidized to Se(VI) by K2FeO4, and the Se(VI) species was reduced to insoluble Se(0) by γ-Fe2O3-Mn(II) nanocomplex. Insoluble Se(0) adsorbed on the surface of Fe-Mn particle and coprecipitated, thus removed from aqueous solution. As solution pH varied from 4.0 to 8.0, Se(IV) removal ratio ranged from 89% to 98% in the system. Co-existing ions such as Na+, Ca2+ and SO42− had no intense effect on Se removal, while PO43- and humic acid (HA) inhibited Se removal in Mn(II)/K2FeO4 system. Mn(II)/K2FeO4 was an effective and convenient way for Se(IV) removal from polluted water.

12855. 题目: Millennial-scale changes in the molecular composition of Posidonia australis seagrass deposits: Implications for Blue Carbon sequestration
文章编号: N19100504
期刊: Organic Geochemistry
作者: Joeri Kaal, Oscar Serrano, Antonio Martínez Cortizas, Jeffrey A. Baldock, Paul S. Lavery
更新时间: 2019-10-05
摘要: Seagrass ecosystems are recognised for their role in climate change mitigation, due to their capacity to form organic-rich sediments. The chemical recalcitrance of seagrass organs is one characteristic driving carbon storage, but the molecular background of this feature is poorly understood. We assessed molecular composition changes of Posidonia australis sheaths (SH) and roots plus rhizomes (RR) along a sediment core, encompassing 3200 cal. yr BP, by means of nuclear magnetic resonance spectroscopy (13C NMR), conventional analytical pyrolysis (Py-GC–MS) and thermally assisted hydrolysis and methylation (THM-GC–MS). Significant trends with depth (age) in the composition of both SH and RR remains of P. australis were observed from all methods. In general terms, polysaccharides become depleted (degraded) and lignin enriched (selectively preserved) as age increases, and the minor constituents cutin, suberin and condensed tannin are also preferentially depleted during ageing in both fractions. Molecular changes with ageing were smaller in SH, especially regarding polysaccharides, indicative of a superior stability compared to RR. The molecular changes observed are most pronounced within the first 75 cm of the record, which reflects the recalcitrance of P. australis detritus once it is buried below that depth (corresponding to approximately 700 cal. yr BP). The capacity of P. australis to act as a long-term carbon sink seems to be mainly related to the resistance of buried lignocellulose materials to decomposition. The results on diagenetic effects on the molecular fingerprint of seagrass detritus contribute to our understanding of carbon sequestration in Blue Carbon ecosystems. Furthermore, data comparison of the methods applied using principal component analysis (PCA) allowed us to identify consistencies, discrepancies and complementarities.
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12856. 题目: A hydraulically optimized fluidized bed UF membrane reactor (FB-UF-MR) for direct treatment of raw municipal wastewater to enable water reclamation with integrated energy recovery
文章编号: N19100503
期刊: Separation and Purification Technology
作者: Nils Horstmeyer, Cornelius Thies, Thomas Lippert, Jörg E. Drewes
更新时间: 2019-10-05
摘要: A hydraulic optimized pilot-scale fluidized bed ultrafiltration membrane reactor (FB-UF-MR) for water reclamation with integrated energy recovery was designed and operated for 576 days with raw municipal wastewater from a local wastewater treatment plant (WWTP). The design of the reactor and the fluidized bed flow regime was optimized by a computational fluid dynamic (CFD) model. By adopting a customized impact plate in the design, the recirculation flow rate could be reduced by approximately 38% lowering the energy demand significantly. Granular activated carbon (GAC) was used as fluidized medium and proofed as successful fouling mitigation strategy, even at low concentrations of 1.7–3.3 g/L (based on total reactor volume) or 21–41 g/L (based on fluidized bed volume) as compared to previous studies. The optimal operational conditions of the FB-UF-MR were identified at (i) a sustainable flux of 8–10 LMH, (ii) an optimal backwash flux of 1.2 times of the permeate flux, (iii) an operational cycle of 10 min consisting of 9 min filtration and 30–60 sec backwashing and optional 30 sec relaxation. Chemical cleaning was applied every 4–6 weeks during long-term operation. Main foulants of the wastewater matrix were identified by 3D-fluorescence excitation-emission matrix (3D-EEM) measurements coupled with parallel factor (PARAFAC) analysis suggesting that protein-like organic matter were the main constituent of the cake layer. The results of this study indicate that direct treatment of raw municipal wastewater with UF is a promising option. Thus, it is possible to concentrate C and N (in a subsequent treatment step) for improved energy recovery while facilitating water reclamation.

12857. 题目: Interactions between biochar and nitrogen impact soil carbon mineralization and the microbial community
文章编号: N19100502
期刊: Soil and Tillage Research
作者: Shuailin Li, Shuo Wang, Miaochun Fan, Yang Wu, Zhouping Shangguan
更新时间: 2019-10-05
摘要: Adding biochar (BC) to soils is proposed to enhance carbon sequestration in agricultural soils. However, there is limited knowledge regarding the effects of the interactions between BC and nitrogen (N) on soil organic carbon (SOC) mineralization at an interannual scale. We conducted a three-year field experiment to systematically reveal the impacts of BC combined with N fertilizer on a silty clay soil, including its physicochemical properties, soil respiration characteristics and microbial community. BC applied once at 0, 20 and 40 t ha−1 (B0, B1 and B2, respectively) was combined with three N fertilization levels (0, 120 and 240 kg N ha−1; N0, N1 and N2, respectively). Only winter wheat (Triticum aestivum L.) was cultivated, and it was cultivated in a winter wheat-summer fallow crop system. BC application persistently increased the SOC content by 36.3–91.6% over three years. Several soil parameters were also improved by BC combined with N after one year, such as bulk density, NO3- and available P content. Compared with its values with B0 treatments with N1 or N2, the total soil CO2 emitted decreased by 6.7–8.9% in response to BC combined with N1 but increased by 5.9–7.5% in response to BC combined with N2. B1N1 not only significantly increased microbial biomass but also decreased qCO2. In addition, B1N1 in particular increased the relative abundances of members of the microbial population associated with increased microbial C use efficiency, such as Rhizopus and Helotiaceae. However, B2N1 and B2N2 strongly disturbed the soil microbial ecosystem; moreover, the lowest alpha diversity of the bacterial community was observed in B2N2 soils. In summary, adding BC at a high rate to N-fertilized soil strongly disturbs the soil microbial ecosystem and reduces the C-sequestering potential of soil, while B1N1 treatment is recommended to enhance soil C sequestration and improve soil fertility under dryland farming.

12858. 题目: Multiple biomarkers highlight the importance of water column processes in treatment wetland organic matter cycling
文章编号: N19100501
期刊: Water Research
作者: Elise S. Morrison, Michael R. Shields, Thomas S. Bianchi, Yina Liu, Sue Newman, Nikola Tolic, Rosalie K. Chu
更新时间: 2019-10-05
摘要: A suite of biomarkers, including amino acids, pigments, and lignin phenols coupled with high resolution mass spectrometry were used to evaluate differences in the sources and fate of organic matter (OM) in Everglades treatment wetlands as a model for OM cycling in shallow water wetlands. Five components of the system (water column particulate matter, vertical traps, flocculent material, periphyton, and surface soil) were assessed for OM transformations down-profile (i.e. water column to soil) and between treatment cells dominated by emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV), with comparisons to reference sites within the remnant Everglades. We found that OM cycling is fundamentally different between EAV and SAV wetlands, and that SAV wetlands have some shared characteristics with similar habitats in the remnant Everglades. Other than locations densely populated by Typha spp., water column particulate organic C was predominantly derived from microbial/cryptomonad sources, rather than macroscopic sources (vascular plants and algal mats). Bacterial amino acid biomarkers were positively correlated with amino acid degradation indices and organic P (Po), respectively suggesting that microbial abundance is associated with less degraded OM, and that further investigation into relationships between microbial biomass and Po is warranted. Overall, this multi-biomarker approach can elucidate the relative degradation of OM pools, identify sources of OM, and highlight the importance of water column processes in shallow water wetlands.
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12859. 题目: Source of organic detritus and bivalve biomass influences nitrogen cycling and extracellular enzyme activity in estuary sediments
文章编号: N19100401
期刊: Biogeochemistry
作者: Josie Crawshaw, Theresa O’Meara, Candida Savage, Blair Thomson, Federico Baltar, Simon F. Thrush
更新时间: 2019-10-04
摘要: In aquatic ecosystems, natural processes that remove nitrogen from the biologically available pool (e.g. denitrification) have been intensively studied as an ecosystem function that reduces eutrophication. The quantity of sediment organic matter is a key driver of denitrification with percent organic content positively related to rates of nitrogen removal; however, few studies have investigated the influence of the quality of organic matter on nitrogen cycling in estuarine sediments despite shifts in primary producers with eutrophication. This laboratory study using intact benthic communities investigates the influence of various organic detritus sources, which vary in their C:N ratio, on nitrogen gas (N2) and solute fluxes and extracellular enzyme activity in estuarine sediments. A custom-built tank with a removable front plate was used with a planar optode film to image sediment oxygenation. Mangrove leaf detritus significantly increased the net N2 production in sediments, while the deposition of other detrital sources and control sediments produced net N2 consumption. Sulfatase activity was significantly reduced in the mangrove leaves and seagrass treatments, suggesting alteration of heterotrophic microbial activity with reducing oxygen conditions. Leucine aminopeptidase activity, indicating nitrogen cycling, was reduced in all treatments, suggesting the organic detritus provided a nitrogen supplement or reduced the activity of extracellular enzymes producing microbes. Bivalve biomass increased net nitrogen gas fluxes in some treatments. Our results indicate different detrital sources may have varying impacts on the removal of bioavailable nitrogen through denitrification and show that feedbacks in biogeochemical cycles may occur with changes in organic detrital source pools.

12860. 题目: Effects of magnesium ferrite biochar on the cadmium passivation in acidic soil and bioavailability for packoi (Brassica chinensis L.)
文章编号: N19100303
期刊: Journal of Environmental Management
作者: Xing Gao, Yutao Peng, Yaoyu Zhou, Muhammad Adeel, Qing Chen
更新时间: 2019-10-03
摘要: Biochar (BC) and magnesium ferrite (MF) have been used in effective adsorption of cadmium (Cd) in aqueous environment, whereas little is known about the effect of their composite on Cd adsorption and Cd-contaminated soil remediation. In this study, biochar (BC), magnesium ferrite (MF) and biochar assembled with magnesium ferrite (MB) were prepared for Cd adsorption and then applied in soils (1–2% w/w) to investigate their effects on Cd passivation by performing leaching experiments and early stage seeding growth test for packoi (Brassica chinensis L.). Compared with the BC and MF, the MB showed greater adsorption property for Cd at aqueous solution (31.3 mg/g) and amended soils (1.85 mg/g at 2% applied rate) based on the isotherms studies. Besides, the MB performed the better passivation ability in reduction of the bioavailable Cd and seeding growth experiment. Solid state analysis of the materials before and after leaching indicated that the passivation mechanism may be dominated by ion exchange and surface complexation. Principal component analysis revealed that the soil pH and adsorption capacity had the strong correlation with the contents of bioavailable-Cd and seedling growth. These results indicated that MB could be used as an efficient amendment in Cd contaminated soil for reducing bioavailable Cd concentrations and improving plant growth.
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