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25961. 题目: From peat swamp forest to oil palm plantations: The stability of tropical peatland carbon
文章编号: N19022102
期刊: Geoderma
作者: Hannah V. Cooper, Christopher H. Vane, Stephanie Evers, Paul Aplin, Nicholas T. Girkin, Sofie Sjögersten
更新时间: 2019-02-21
摘要: Accurate assessment of tropical peatland carbon dynamics is important to (a) determine the size of the active carbon pool, (b) estimate the scale of transfers of peat-derived greenhouse gases (GHGs) to the atmosphere resulting from land use change, and (c) support carbon emissions reduction policies. To date, information on the quality of tropical peatland organic matter and its sensitivity to increases in global temperatures is limited, particularly in the context of land conversion. The aim of this work is therefore to determine peat quality and temperature response of potential GHG emissions under flooded conditions from tropical peatland sites. Whilst reflecting the process of conversion from forest to oil palm plantation. Four land use types that represent the stages of conversion from peat swamp forest to oil palm were chosen: (i) secondary ‘forest’, (ii) recently ‘drained’ but not cleared forest (iii) cleared and recently planted ‘young oil palm’ plantation and (iv) ‘mature oil palm’ plantation. Overall, surface peat carbon was more labile than deeper peats. The largest labile pool was measured at forest sites. In the later stages of land conversion, the labile carbon had been lost and the relative abundance of recalcitrant organic material increased. Potential GHG fluxes were greatest in surface peats compared to deeper peats and declined as labile carbon was depleted following land conversion. Higher temperatures resulted in higher potential GHG emissions at all stages of conversion, but the magnitude of the temperature response depended on organic matter lability. For CO₂ fluxes, the temperature response was most pronounced at forest sites. This reflects the greater peat lability at this land use. In contrast, for CH₄ emissions, there were increased emissions both at forest and converted land types with higher temperatures. This suggests that increasing temperatures in response to climate warming may drive higher CH₄ emissions from sites dominated by degraded organic matter. Collectively, this study demonstrates that during conversion from peat swamp forest to oil palm plantation, the enhanced decomposition and reduced litter input rates is reflected eventually in reduced potential gross CO₂ emissions from peat. Nonetheless higher temperature resulting from climate warming may maintain high GHG emissions at plantation sites.

25962. 题目: Removal of Cyanotoxins by Potassium Permanganate: Incorporating Competition from Natural Water Constituents
文章编号: N19022101
期刊: Water Research
作者: Juliana R. Laszakovits, Allison A. MacKay
更新时间: 2019-02-21
摘要: In recent years, harmful algal blooms capable of producing toxins including microcystins, cylindrospermopsin, and saxitoxin have increased in occurrence and severity. These toxins can enter drinking water treatment plants and, if not effectively removed, pose a serious threat to human health. The work here investigated the efficacy of permanganate oxidation as a treatment strategy, with a focus on incorporating competition by cyanobacterial cells and dissolved organic matter (DOM). We report rate constants of 272 ± 23 M^-1 s-for the reaction between permanganate and microcystin-LR, 0.26 ± 0.05 M^-1 s^-1 for the reaction between permanganate and cylindrospermopsin, and, using chemical analogues, estimate a maximum rate constant of 2.7 ± 0.2 M^-1 s^-1 for the reaction between permanganate and saxitoxin. We conclude that permanganate only shows potential to remove microcystins. No pH (6-10) or alkalinity (0-50 mM) dependence was observed for the rate of reaction between microcystin-LR and permanganate; however, a temperature dependence was observed and can be characterized by an activation energy of 16 ± 5 kJ mol^-1. The competition posed by cyanobacterial cells was quantified by an apparent second order rate constant of 2.5 ± 0.3 x 10-6 L μg chl-a^-1 s^-1. From this apparent second order rate constant, it was concluded that cyanobacterial cells are not efficient scavengers of permanganate within typical contact times but this second order rate constant can be used to accurately predict microcystin degradation in algal-impacted waters. The competition posed by DOM depended on both the amount of DOM present (as measured by TOC) and its electron donating capacity (as predicted by SUVA-254 or E2/E3 ratio). DOM was concluded to scavenge permanganate efficiently and we forward that this should be considered in permanganate dosing calculations.
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25963. 题目: Effect of biochar on fraction and species of antimony in contaminated soil
文章编号: N19022013
期刊: Journal of Soils and Sediments
作者: Li Hua, Huan Zhang, Ting Wei, ChunYan Yang, JunKang Guo
更新时间: 2019-02-20
摘要: Purpose: Antimony (Sb) is a highly toxic heavy metal, and its amount in soil is increasing due to anthropogenic activities. Excessive Sb intake could ultimately threat human health. Recently, biochar (BC) has been accepted for remediation of Sb-contaminated soil. Understanding the interaction between BC and Sb and the effect of BC-induced changes in soil properties on immobilization/mobilization of Sb will help, therefore, to elucidate the mechanism of BC in immobilization/mobilization of Sb in contaminated soils. Materials and methods: Wheat straw-derived BC (SBC) and fruit (apple) tree-derived BC (FBC) were obtained at the pyrolysis temperatures of 500 °C. Sb-contaminated soil was incubated with/without 0.5, 5, or 10 wt% of SBC and FBC for 130 days. Change of soil properties induced by BC was explored during the incubation. Dynamic change of Sb fraction and speciation were assessed by the sequential chemical extraction and citric acid extraction, respectively. The X-ray photoelectron spectroscopy (XPS) was employed to check elemental change of soil with 10% SBC at different incubation times. The correlation analysis and principal component analysis (PCA) were used to analyze relationship between Sb immobilization/mobilization and change of soil properties induced by BC. Results and discussion: The obvious change of soil properties can be observed when the soil was treated with 10% BC instead of 5 and 0.5% BC. During the first 20 days with SBC incubation and 50 days with FBC incubation, Sb mobilization increased may be because of the electrostatic repulsion of functional groups in BC; OM and functional group of BC govern the reduction reactions, anionic competition, electrostatic repulsion, and biological reduction in soil induced by BC. By contrast, after 20 days with SBC incubation and 50 days with FBC incubation, the mobilization of Sb decreased, which may be attributed to the formation of complexes between Sb and OM of BC, secondary mineral precipitation, and organic complex between Sb and humus acid in soil induced by BC. Conclusions: It is noteworthy that the application of BC has a potential mobilizing risk for Sb and the final effect depends on BC characteristic and the change of soil properties induced by BC. The possible risks induced by BC should be considered before applying the BC to Sb-contaminated soil.

25964. 题目: Formation of macromolecules with peptide bonds via the thermal evolution of amino acids in the presence of montmorillonite: Insight into prebiotic geochemistry on the early Earth
文章编号: N19022012
期刊: Chemical Geology
作者: Hongling Bu, Peng Yuan, Hongmei Liu, Dong Liu, Zonghua Qin, Xuemin Zhong, Hongzhe Song, Yun Li
更新时间: 2019-02-20
摘要: The formation of macromolecules is an indispensable step in the process leading to the appearance of life on Earth. As their constituents were widely distributed over geological time and space on the surface of the primitive Earth, clay minerals are regarded as an essential factor influencing the formation of macromolecules due to their high reactivity and their close association with organic matter that could be the precursors of macromolecules. Over the years, many researchers have studied the roles of clay minerals in macromolecules formation through the condensation of amino acids (AAs) in aqueous systems in order to understand the thermal evolution of organic matter (OM) in pristine oceans. However, the condensation of AAs in non-aqueous systems has received limited attention. In particular, the stability and evolution of AAs in volcanic eruption environments that are rich in clay minerals have rarely been investigated. In this work, the influence of clay mineral on the thermal evolution of AAs was studied. Two types of clay-AA complexes, i.e., clay-AA interlayer complexes and clay-AA external complexes (where AAs exist outside the interlayer structure) were used. An expandable clay mineral, montmorillonite (Mt), was chosen as the typical clay mineral, and L-arginine (Arg) and glycine (Gly) were used as the model amino acids for the preparation of clay-AA complexes. In situ diffuse-reflectance infrared Fourier transform spectroscopy (in situ DRIFT) was used to monitor the thermal evolution behaviors of the clay-AA complexes, such as the formation of macromolecules with peptide bonds, and thermogravimetry (TG) and TG coupled with Fourier transform infrared spectroscopy (TG-FTIR) analyses were used to investigate the decomposition of the produced macromolecules. The results show that Mt strongly affects macromolecule formation during the thermal evolution of AA, which is mainly due to that the inherent solid acidity of the different structural sites of Mt varies. When AAs are present on the external surfaces of Mt, the interaction between AA and clay minerals substantially decreases the initial formation temperature of the macromolecules with peptide bonds (for Arg) and strongly affects the types of condensation products (for Gly). When AAs exist in the interlayer structure of Mt, the interlayer structure has a steric effect on the thermal evolution of these monomers, which, together with the effects of the molecular structure of Arg, enhances the initial temperature of condensation and increases the thermal decomposition temperature of the formed macromolecules. Regardless of whether AAs exist in the interlayer sites or on the external surfaces of clay minerals, clay-OM association is able to protect macromolecules, postponing their thermal decomposition. The present work indicates that macromolecules with peptide bonds could readily form via the condensation of AAs under dry high-temperature conditions, which implies that non-aqueous thermal conditions resulting from volcanic activities might be a favorable geological setting for prebiotic chemical evolution on the early Earth.

25965. 题目: Biochar alleviates fluoride toxicity and oxidative stress in safflower (Carthamus tinctorius L.) seedlings
文章编号: N19022011
期刊: Chemosphere
作者: Kazem Ghassemi-Golezani, Salar Farhangi-Abriz
更新时间: 2019-02-20
摘要: An original research was laid out as factorial to evaluate the possible effects of biochar (0, 25 and 50 g kg⁻¹ soil) on mitigating fluoride toxicity (non-contamination, 100, 200, 400 and 800 mg NaF kg⁻¹ soil) in safflower seedlings. Increasing fluoride toxicity up to 200 mg NaF kg⁻¹ soil did not decrease the safflower growth. However, the growth of plants under 400 and 800 mg NaF kg⁻¹ was reduced by enhancing soluble fluoride concentration in the soil. This growth reduction was the consequence of an increase in fluoride content of plant tissues, generation of super oxide radicals and hydrogen peroxide, lipid peroxidation, misbalancing potassium and calcium ions, and a decrease in synthesis of photosynthetic pigments including chlorophylls, carotenoids, anthocyanin, flavonoids and xanthophyll's and photochemical efficiency of photosystem II. Application of biochar decreased the fluoride solubility, fluoride content of plant tissues, oxidative stress and antioxidant enzymes activities, leading to an increase in cation exchange capacity of soil and the pH, calcium and potassium uptakes, maximum efficiency of photosystem II, synthesis of photosynthetic pigments, and plant growth. In general, addition of 50 g biochar to 1 kg soil was the best treatment for alleviation of the fluoride toxicity in safflower plants.
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25966. 题目: Effect of oxygen supply strategy on nitrogen removal of biochar-based vertical subsurface flow constructed wetland: Intermittent aeration and tidal flow
文章编号: N19022010
期刊: Chemosphere
作者: Jing Li, Zhen Hu, Fazhan Li, Jinlin Fan, Jian Zhang, Fengmin Li, Hongying Hu
更新时间: 2019-02-20
摘要: Insufficient dissolved oxygen (DO) concentration is recognized as one of the major factors limiting efficient nitrogen removal in constructed wetlands (CWs). This study investigated four biochar-based vertical subsurface flow constructed wetlands (VSFCWs) (system I: intermittent aeration without biochar addition; system II: intermittent aeration with biochar addition; system III: tidal flow without biochar addition; system IV: tidal flow with biochar addition) to compare the effect of oxygen supply strategies on the performance and mechanism of nitrogen removal. The results showed that NH₄⁺N removal efficiencies were 85.83%, 87.88%, 96.19%, and 98.30% for systems I–IV respectively. The abundance of microbes involved in nitrogen transformation also increased in all VSFCWs, particularly in the tidal flow mode with biochar addition. The higher oxygen utilization rate and higher surface area provided by biochar could significantly improve microbial abundance and then enhance nitrogen removal. Most notably, the rate of nitritation (2.92, 3.82, 3.14 and 4.27 mg N L⁻¹ h⁻¹) was higher than that of nitration (0.51, 0.66, 0.83 and 0.89 mg N L⁻¹ h⁻¹) in systems I–IV, respectively, and the percentages of NO₂⁻-N denitrified via simultaneous nitrification denitrification (SND) in systems I–IV were 58.20%, 55.10%, 50.89% and 51.89%, respectively. Therefore, in addition to conventional nitrification denitrification, partial nitrification and SND via NO₂⁻-N were also the significant nitrogen transformation pathways in the four VSFCWs at high DO concentrations (2.43–6.84 mg L⁻¹). These results demonstrated that the tidal flow biochar-based VSFCWs performed well in nitrogen removal due to efficient oxygen supplementation and enhanced microbial community abundance.

25967. 题目: Distribution characteristics of poly-brominated diphenyl ethers between water and dissolved organic carbon from anaerobic digestate: Effects of digestion conditions
文章编号: N19022009
期刊: Chemosphere
作者: Chen Shi, Yong Hu, Takuro Kobayashi, Nan Zhang, Zhenyi Zhang, Hidetoshi Kuramochi, Hidenori Matsukami, Zhenya Zhang, Kai-Qin Xu
更新时间: 2019-02-20
摘要: It is becoming increasingly urgent to investigate the partition coefficients (expressed as log K_DOC values) of polybrominated diphenyl ethers (PBDEs) in dissolved organic carbon (DOC) present in wastewater. In the current study, after 72 h of equilibration, the concentrations of four common PBDEs were measured in the presence of four DOC solutions from two laboratories and two full-scale anaerobic digestion plants. Sixteen log K_DOCs were determined by calculation and unit conversion. The results for the laboratory samples, such as log K_DOCs for 2,2′,4,4′,5,5′-hexabromodiphenyl ether being 6.38 and 5.46 at different reaction temperatures during the cultivate procedure, suggest that a thermophilic environment promotes the solubility of PBDEs to a greater extent than mesophilic conditions. DOC composition directly influences the solubility of PBDEs, even at the same cultivating temperature: the highest log K_DOCs for 2,2′,4,4′,5,6′-hexabromodiphenyl ether were 6.71 and 6.33 in different full-scale plant digestates. A linear regression with an R² of 0.9863 was used to construct a model describing the potential relationship between log K_DOC and the composition of DOC, which includes proteins, polysaccharides and lipids, and which takes into account the positions of bromine atoms, for use in predicting the log K_DOC values of PBDEs in different water systems.
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25968. 题目: Effects of changing permafrost conditions on hydrological processes and fluvial fluxes
文章编号: N19022008
期刊: Earth-Science Reviews
作者: Melissa J. Lafrenière, Scott F. Lamoureux
更新时间: 2019-02-20
摘要: This paper reviews the impacts of permafrost change on hydrological and related hydrochemical, particulate and organic fluxes in small Arctic catchments. While the emphasis is directed at High Arctic systems, literature and recent developments from other Arctic regions are also included. Hydrological change, particularly a shift from nival (snowmelt) dominance to increasing pluvial (rainfall) runoff contributions has important consequences for the timing and magnitude of hydrological fluxes. A key distinction is made between thermal perturbation, where changing melt season thaw conditions result in deep thaw with minimal geomorphic or surface hydrological effects, in contrast to physical perturbation, where permafrost change results in some form of thermokarst or physical disturbance such as mass movement or enhanced erosion. The latter disturbances are commonly expressed as localized thermo erosional gullies, active layer detachments and retrogressive thaw slumps. Results from recent research emphasise the importance of hydrological connectivity in terms of the downstream effect of a particular permafrost perturbation. Well-connected systems, either at the surface as channelized flows, or in the subsurface, through new or altered active layer flow pathways, result in substantial changes in downstream fluvial fluxes. Surface hydrological connectivity of localized permafrost disturbances increases transport of suspended sediment and particulate organic matter, the latter of which is often old and comparatively labile. Exposed ice in retrogressive thaw slumps sustains discharge during the melt season, further increasing fluxes. Thermal perturbation holds a substantially greater potential downstream impact due to widespread mobilization of solutes and dissolved organic carbon and nitrogen, and several studies point to rapid microbial alteration of carbon and inorganic nitrogen transformation in the shallow subsurface. Collectively, these results point to altered runoff, sediment transport and hydrochemical fluxes with spatial and hydrological controls.

25969. 题目: Lignin as an effective agent for increasing the separation performance of crosslinked polybenzoxazine based membranes in pervaporation dehydration application
文章编号: N19022007
期刊: Journal of Membrane Science
作者: Yu-Ting Chen, Yi-Ling Liao, Yi-Ming Sun, Chien-Chieh Hu, Juin-Yih Lai, Ying-Ling Liu
更新时间: 2019-02-20
摘要: This work reports the utilization of lignin, a renewable and biomass-based material, as an effective modifying agent for thermally stable and hydrophobic membranes based on crosslinked polybenzoxazine (CRPBz) to significantly enhance their permeation fluxes in pervaporation dehydration tests. Lignin could involve in the crosslinking reaction of polybenzoxazine so as to be chemically embedded in the polymer networks. In addition to the inherent hydrophilicity of lignin, lignin could release the hydrophilic groups (phenol and tertiary amine) of crosslinked polybenzoxazine with formation of hydrogen bonding with crosslinked polybenzoxazine, consequently to significantly enhance the hydrophilicity and water permeation fluxes of the studied membranes. With feeding a 70 wt% tetrahydrofuran aqueous solution at 25 °C, lignin modification increases the permeation flux of the CRPBz based membrane from 237 g m⁻² h⁻¹ to 490 g m⁻² h⁻¹ and separation factor from 11,920 to 19,440. Lignin modification significantly enhances the water permeation flux of the membrane without scarifying separation ability. A 3.4-folds of pervaporation separation index (PSI, the product of permeation flux and separation factor) has been demonstrated with the lignin modification. Similar performance has also been recorded on the tests on a 70 wt% isopropanol aqueous solution. The effect of lignin has been attributed to increase the membrane hydrophilicity for facilitating water permeation. The results demonstrate the wide application scopes of the lignin-modified CRPBz based membranes in pervaporation dehydration based on their high stability and hydrophilicity.
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25970. 题目: Remediation efficiency of different methods for rapid-response of microbiological and/or organic matter contaminated beach sand: A laboratory study
文章编号: N19022006
期刊: Marine Pollution Bulletin
作者: Renan C. Testolin, André O.S. Lima, Jéssica M. Strutz, Rogério Corrêa, Gabriel Poyer-Radetski, Lucas Cesconetto, Amira Felde, Claudemir M. Radetski
更新时间: 2019-02-20
摘要: In this article we compare the efficiency of different methods of rapid-response remediation of beach sand contaminated with microbiological and/or organic matter. Contaminated beach sands were treated in laboratory by different treatment methods (i.e., oxidation, UV-photoexposure, or thermal methods) and the efficiency of disinfection and breakdown of organic matter were evaluated. Contaminants in raw and treated beach sands were measured by membrane filtration method, and by chemical and biochemical oxygen demand, and chromatographic analysis. All the methods tested were efficient for disinfecting beach sand with microbiological contamination, except for the UV-photoexposure method, which showed only moderate disinfection potential. Chemical degradation efficiency of beach sand contaminated by crude petroleum was higher with Fenton and Photo-Fenton (associated with the use of surfactant and ultrasound) methods. Photo-Fenton method improvement can increase the efficiency of contaminated beach sand treatment, and can also help beach managers when selecting which method to adopt for remedial actions.

25971. 题目: Development of a novel aerosol generation system for conducting inhalation exposures to ambient particulate matter (PM)
文章编号: N19022005
期刊: Science of The Total Environment
作者: Sina Taghvaee, Amirhosein Mousavi, Mohammad H. Sowlat, Constantinos Sioutas
更新时间: 2019-02-20
摘要: In this study, we developed a novel method for generating aerosols that are representative of real-world ambient particulate matter (PM) in terms of both physical and chemical characteristics, with the ultimate objective of using them for inhalation exposure studies. The protocol included collection of ambient PM on filters using a high-volume sampler, which were then extracted with ultrapure Milli-Q water using vortexing and sonication. As an alternative approach for collection, ambient particles were directly captured into aqueous slurry samples using the versatile aerosol concentration enrichment system (VACES)/aerosol-into-liquid collector tandem technology. The aqueous samples from both collection protocols were then re-aerosolized using commercially available nebulizers. The physical characteristics (i.e., particle size distribution) of the generated aerosols were examined by the means of a scanning mobility particle sizer (SMPS) connected to a condensation particle counter (CPC) at different compressed air pressures of the nebulizer, and dilution air flow rates. In addition, the collected PM samples (both ambient and re-aerosolized) were chemically analyzed for water-soluble organic carbon (WSOC), elemental and organic carbon (EC/OC), inorganic ions, polycyclic aromatic hydrocarbons (PAHs), and metals and trace elements. Using the aqueous filter extracts, we were able to effectively recover the water-soluble components of ambient PM (e.g., water-soluble organic matter, and water-soluble inorganic ions); however, this method was deficient in recovering some of the important insoluble components such as EC, PAHs, and many of the redox-active trace elements and metals. In contrast, using the VACES/aerosol-into-liquid collector tandem technology for collecting ambient PM directly into water slurry, we were able to preserve the water-soluble and water-insoluble components very effectively. These results illustrate the superiority of the VACES/aerosol-into liquid collector tandem technology to be used in conjunction with the re-aerosolization setup to create aerosols that fully represent ambient PM, making it an attractive choice for application in inhalation exposure studies.
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25972. 题目: Applying reverse stable isotope labeling analysis by mid-infrared laser spectroscopy to monitor BDOC in recycled wastewater
文章编号: N19022004
期刊: Science of The Total Environment
作者: S.M. Schulte, D. Köster, M.A. Jochmann, R.U. Meckenstock
更新时间: 2019-02-20
摘要: Biological stability of treated wastewater is currently determined by methods such as biological oxygen demand, ATP-quantification, or flow-cytometric cell counting. However, the continuous increase in water reclamation for wastewater reuse requires new methods for quantifying degradation of biodegradable dissolved organic carbon (BDOC) ranging from very small to high concentrations of dissolved organic carbon (DOC). Furthermore, direct activity measures or absolute concentrations of BDOC are needed that produce comparable and reproducible results in all laboratories. Measuring carbon mineralization by CO₂ evolution presents a suitable approach for directly measuring the microbial degradation activity. In this work, we investigated the extent of BDOC in water samples from effluent of a wastewater treatment plant and after purification by ultrafiltration over 204 days. BDOC monitoring was performed with the recently introduced reverse stable isotope labeling (RIL) analysis using mid-infrared spectroscopy for the monitoring of microbial CO₂ production. Average BDOC degradation rates ranged from 0.11 to 0.32 mg L⁻¹ d⁻¹ for wastewater treatment plant effluent and from 0.03 to 0.22 mg L⁻¹ d⁻¹ after ultrafiltration. BDOC was degraded over >90 days indicating the long-term instability of the DOC. Degradation experiments over 88 days revealed first order kinetic rate constants for BDOC which corresponded to 12.7 · 10⁻³ d⁻¹ for wastewater treatment plant effluent and 2.7 · 10⁻³ d⁻¹ after ultrafiltration, respectively. A thorough sensitivity analysis of the RIL showed that the method is very accurate and sensitive with method detection limits down to 10 μg· L⁻¹ of measured CO₂.
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25973. 题目: Research on the variations of organics and heavy metals in municipal sludge with additive acetic acid and modified phosphogypsum
文章编号: N19022003
期刊: Water Research
作者: Quxiu Dai, Liping Ma, Nanqi Ren, Ping Ning, Zhiying Guo Longgui, Xie
更新时间: 2019-02-20
摘要: Concentration and fraction distribution of organics and heavy metals in municipal sludge treated by modified phosphogypsum and acetic acid (signed as MPG/HAC) were studied. The results showed that MPG/HAC conditioning significantly produce synergistic enhancement effect to dissolution of unstable heavy metals wrapped in the stable colloid network. Simultaneously, after conditioning, about 45.16% of organics such as proteins, polysaccharides and humic acid in supernatant was degraded, thus dissociating large amount of active group which accelerated immobilization of dissolved heavy metals and weaken its toxicity. In addition, MPG with a porous structure could adsorb unstable heavy metals and transform them into residual fraction, leading to a considerable decrease in their mobility risk level. Besides, linear regression models showed that a strong oxidizability of sludge, and destruction of colloidal network could greatly promote dissolution of unstable heavy metals. Simultaneously, sludge oxidizability and organics degradation rate, and disintegration of extracellular polymeric substances (EPS) layer highly accelerate immobilization of unstable metals. Excepting Cd, environmental risk of Cr, Cu, Pb, Zn, Ni and As can be effectively weakened after conditioning. Additionally, MPG/HAC conditioning might be appropriate for stabilization of Cd, Cr and Zn in water supply sludge, especially for Zn.
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25974. 题目: Evaluation of Urea Removal by Persulfate with UV irradiation in an Ultrapure Water Production System
文章编号: N19022002
期刊: Water Research
作者: Jeongyun Choi, Jinwook Chung
更新时间: 2019-02-20
摘要: The removal of urea by persulfate with UV irradiation in an ultrapure water (UPW) production system was examined using a continuously operated column reactor. Urea is a substance that is not properly removed by the unit processes in UPW production systems. Based on our monitoring of urea concentration over 1 year of the operation of a UPW production facility, a relatively high concentration of urea was introduced between February and May in 2016 and the total organic carbon (TOC) concentration of the UPW was increased in that period. Approximately 50% of the urea in the raw water was removed by the UPW production process, for which double-pass reverse osmosis units were instrumental. The addition of persulfate to the TOC reduction UV unit in the UPW production process was examined to improve the efficiency of urea removal. As a result, supplying over 20 μmole/L persulfate to the TOC reduction UV reactor improved the efficiency of urea removal from 9% to 90%. UV dose was an important factor of urea removal. In the ion analysis, nitrate and sulfate were detected in the effluent, and the ratio of produced nitrate to the removed urea was approximately 2.

25975. 题目: Multi‐objective calibration of RothC using measured carbon stocks and auxiliary data of a long‐term experiment in Switzerland
文章编号: N19022001
期刊: European Journal of Soil Science
作者: C. Cagnarini, G. Renella, J. Mayer, J. Hirte, R. Schulin, B. Costerousse, A. Della Marta, S. Orlandini, L. Menichetti
更新时间: 2019-02-20
摘要: Interactions between model parameters and low spatiotemporal resolution of available data mean that conventional soil organic carbon (SOC) models are often affected by equifinality, with consequent uncertainty in SOC forecasts. Estimation of belowground C inputs is another major source of uncertainty in SOC modelling. Models are usually calibrated on SOC stocks and fluxes from long‐term experiments (LTEs), whereas other point data are not used for constraining the model parameters. We used data from an agricultural long‐term (> 65 years) fertilization experiment to test a multi‐objective parameter estimation approach on the RothC model, combining SOC data from different fertilization treatments with microbial biomass, basal respiration and Zimmermann’s fractions data. We also compared two methods to estimate the belowground C inputs: a conventional scaling of belowground biomass from crop harvest yield and an alternative approach based on constant belowground C for cereals measured experimentally in the field. The resulting posterior parameter distributions still suffered from some equifinality; the most stable C pool kinetic constants and composition of exogenous organic matter were the most sensitive parameters. The use of fixed belowground C inputs for cereals improved the model performance, reducing the importance of treatment‐specific parameters and processes. The introduction of microbial biomass and basal respiration data was effective for increasing determination of the calibration, but also suggested a change in the model structure: the microbial biomass pool, which is proportional to the C inputs in the traditional models, could be represented by different microbial physiology functions.

25976. 题目: Triplet-State Photochemistry of Dissolved Organic Matter: Triplet-State Energy Distribution and Surface Electric Charge Conditions
文章编号: N19021916
期刊: Environmental Science & Technology
作者: Huaxi Zhou, Shuwen Yan, Lushi Lian, Weihua Song
更新时间: 2019-02-19
摘要: Excited triplet states of chromophoric dissolved organic matter (³CDOM*) are highly reactive species in sunlit surface waters and play a critical role in reactive oxygen species (ROS) formation and pollutant attenuation. In the present study, a series of chemical probes, including sorbic acid, sorbic alcohol, sorbic amine, trimethylphenol, and furfuryl alcohol, were employed to quantitatively determine ³CDOM* and ¹O₂ in various organic matters. Using a high concentration of sorbic alcohol as high-energy triplet states quencher, ³CDOM* can be first distinguished as high-energy triplet states (>250 kJ mol^–1) and low-energy triplet states (<250 kJ mol^–1). The terrestrial-origin natural organic matter (NOM) was found to mainly consist of low-energy triplet states, while high-energy triplet states were predominant in autochthonous-origin NOM and effluent/wastewater organic matter (EfOM/WWOM). The ¹O₂ quantum yields and electron transfer quantum yield coefficients (f_TMP) generated from low-energy triplet states remained constant in all tested organic matters. External phenolic compound showed quenching effects on triplet-state formation and tended to have a higher quenching efficiency for aromatic ketone triplet states, which are the main high-energy triplet states. In comparison with terrestrial-origin NOM, autochthonous-origin NOM and EfOM/WWOM presented lower reaction rate constants for sorbic amines and higher reaction rate constants for sorbic acid, and these differences are likely due to dissimilar surface electric charge conditions. Understanding the triplet-state photochemistry of CDOM is essential for providing useful insights into their photochemical effects in aquatic systems

25977. 题目: Sorption of copper and norfloxacin onto humic acid: effects of pH, ionic strength, and foreign ions
文章编号: N19021915
期刊: Environmental Science and Pollution Research
作者: Ling Zhao, Juan Liu, Hui Wang, Yuan-hua Dong
更新时间: 2019-02-19
摘要: Copper (Cu) and norfloxacin (Nor) are frequently used as feed additives for animal growth promotion, which results in a great probability of Cu²⁺ and Nor coexisting in animal excretion and in soils. Sorption of Cu²⁺ and Nor on soil organic matter (SOM) can markedly affect their environmental fate. Thus, humic acid (HA), a major fraction of SOM, was chosen to investigate the cosorption behaviors of Cu²⁺ and Nor on HA under different solution chemistry conditions (pHs, ionic strengths, and foreign ions). The addition of Nor decreased the maximum adsorption capacity (Q_m) of Cu²⁺ and an increasing effect was observed with increasing Nor concentration. Meanwhile, the addition of Cu²⁺ also markedly inhibited the sorption of Nor on HA. The Q_m of Cu²⁺ increased with increasing pH from 3.0 to 5.0 whether Nor was present or not, but more addition of Nor led to less increment in Q_m of Cu²⁺ at the same pH. The Q_m of Nor was observed at pH 4.0 without Cu²⁺, but that was found at pH 5.0 and 3.0 with the addition of 20 and 100 mg L⁻¹ Cu²⁺, respectively. The sorption of Cu²⁺ on HA decreased with increasing ionic strength and followed an order of NaH₂PO₄ > Na₂SO₄ ≈ NaNO₃ at pH 5.0 whether Nor was present or not. Additionally, the higher valence cation had a stronger inhibition effect on Cu²⁺ sorption. The competition between Cu²⁺ and Nor for sorption on HA under the same conditions indicated that the coexistence of Cu²⁺ and Nor may enhance the feasibility of their mobility and environmental risk.

25978. 题目: Homogenization of dissolved organic matter within a river network occurs in the smallest headwaters
文章编号: N19021914
期刊: Biogeochemistry
作者: Ashley A. Coble, Lauren E. Koenig, Jody D. Potter, Lucy M. Parham, William H. McDowell
更新时间: 2019-02-19
摘要: Understanding the drivers of variability in the concentration and composition of dissolved organic matter (DOM) in running waters is a fundamental challenge for aquatic biogeochemistry. Although multiple conceptual frameworks have been proposed to quantify expected changes in DOM within a river network, few studies have collected data to document the variability of DOM within such a network. We examine spatial and temporal variability in the concentration, optical properties, and biodegradability of DOM within a river network in New Hampshire, U.S.A. We examined dissolved organic carbon (DOC) concentration and DOM optical properties across 21 locations within the Lamprey River network (548 km²) with weekly to monthly sampling for 4 years, and biodegradable DOC (BDOC) at 7 mainstem locations for 1 year. DOC concentration and DOM character were highly heterogeneous at the scale of the smallest streams, where variability in land cover and nutrient concentrations were also greatest. At the landscape scale, DOC concentrations and DOM aromaticity increased with wetland cover and decreased with developed land cover and nitrate concentrations. Despite this heterogeneity across streams, we observed similar synchronous seasonal variation in DOC concentration and DOM character regardless of position within the river network, suggesting that broad environmental factors shape the sources and transport of DOM in river networks. In contrast, variation in BDOC over time or across sites was not strongly related to DOM quality or other predictors. Spatiotemporal patterns in DOM provide insight into the complex processes that influence terrestrial carbon export, in-stream processes, and DOM delivery to downstream ecosystems.

25979. 题目: Estimation of soil organic carbon, nitrogen, and phosphorus losses induced by wind erosion in northern China
文章编号: N19021913
期刊: Land Degradation & Development
作者: Heqiang Du, Tao Wang, Xian Xue, Sen Li
更新时间: 2019-02-19
摘要: The loss of nutrients induced by wind erosion causes serious land degradation. Northern China suffers from severe wind erosion that causes massive amounts of soil nutrients to be lost and result in land degradation. To thoroughly comprehend the mechanisms of land degradation in northern China, the spatio‐temporal distribution of nutrients losses induced by wind erosion must be considered. Therefore, in this study, a wind erosion model was employed to obtain the PM10 emissions in northern China from 2001 to 2014, and the quantities of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) entrained by PM10 were obtained using the integrated soil database of China. The results showed that the losses of SOC, TN, and TP induced by wind erosion were 0.894 Tg/a, 0.184 Tg/a, and 0.123 Tg/a, respectively, and the spatial distributions of these three nutrients differed from one another. According to the Moderate Resolution Imaging Spectroradiometer (MODIS) land‐cover data, the nutrients lost from desert ecosystems contributed the largest fractions of the total nutrients lost in northern China, and the fractions of SOC, TN, and TP losses from the desert ecosystems all exceeded 50%. Following the desert ecosystems, the grassland ecosystems also had higher fractions of nutrients losses. The farmland ecosystems, which were the most severely impacted by human activities, contributed to less than 10% of the total nutrients losses.

25980. 题目: Application of biochar for acid gas removal: experimental and statistical analysis using CO 2
文章编号: N19021912
期刊: Environmental Science and Pollution Research
作者: Hanieh Bamdad, Kelly Hawboldt, Stephanie MacQuarrie, Sadegh Papari
更新时间: 2019-02-19
摘要: Acid gases such as carbon dioxide and hydrogen sulfide are common contaminants in oil and gas operations, landfill gases, and exhaust stacks from power plants. While there are processes currently used to treat these effluents (e.g., amine absorption and adsorption using zeolite), many of these processes require high energy, space, and hazardous chemicals. Removal using biochar derived from the fast pyrolysis of forestry residues represents a more sustainable option. In this study, adsorption using CO₂ as a surrogate for acid gases was investigated using various biochars produced from fast pyrolysis of sawmill residues. Response surface methodology was used to determine operating conditions for maximum adsorption and assess interaction of the adsorption parameters, i.e., temperature, inlet feed flow rate, and CO₂ concentration, on biochar adsorption capacity. The Freundlich isotherm best represented the equilibrium adsorption, and the kinetic model was pseudo first-order. Thermodynamic analysis indicated the adsorption process was spontaneous and exothermic. The biochar had better adsorption capacity relative to commercial zeolite. Our results suggested that biochar could be used as a sustainable and cost-effective option for contaminant removal from acid gases produced in landfill gas treatment, fossil fuel extraction, and/or combustion.