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25601. 题目: The potential for rapid determination of charcoal from wetland sediments using infrared spectroscopy
文章编号: N19123004
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Haidee R. Cadd, Jonathan Tyler, John Tibby, Jeff Baldock, Bruce Hawke, Cameron Barr, Melanie J. Leng
更新时间: 2019-12-30
摘要: Wetland sediments archive information about past terrestrial ecosystem change including variations in fire occurrence and terrestrial carbon fluxes. The charcoal content of sediments is important for understanding past fire regimes, as well as the role this recalcitrant carbon plays in the global carbon cycle. Infrared (IR) spectroscopy provides a rapid, non-destructive and cost effective method for simultaneously analysing numerous organic and inorganic sediment properties. The use of IR spectroscopy is well developed for determining concentrations of total organic carbon (TOC), total nitrogen (TN), biogenic silica and carbonate in lacustrine sediments. In soil science IR spectroscopy is also routinely used to determine charcoal content, however the potential for analysing charcoal content from lacustrine sediments has yet to be investigated. Here we develop IR spectroscopy and partial least squares regressions (PLSR) to predict the charcoal and TOC content of an organic, 130,000 year old sediment sequence from North Stradbroke Island (Minjerribah), Australia. Charcoal concentrations used for model development were derived using both traditional palaeoecological area measures (cm² g⁻¹) and solid state ¹³C nuclear magnetic resonance (¹³C NMR) of poly-aryl structures. The IR PLSR models yielded significant correlations for the two charcoal methodologies (area measurements, R² = 0.57, p < .05; ¹³C NMR, R² = 0.70, p < .05). We additionally find a very strong, significant, correlation for TOC (R² = 0.92, p < .05), consistent with previous studies. Hence, IR is a promising tool for determining the charcoal content of lacustrine sediments, particularly for first-order sample screening, as part of a multi-proxy framework. IR spectroscopy can therefore provide a reliable and rapid technique for the initial investigation of fire histories and organic constituents of sedimentary sequences.

25602. 题目: Pre-ozonation for the mitigation of reverse osmosis (RO) membrane fouling by biopolymer: The roles of Ca²⁺ and Mg²⁺
文章编号: N19123003
期刊: Water Research
作者: Zhonglong Yin, Tiancheng Wen, Yan Li, Aimin Li, Chao Long
更新时间: 2019-12-30
摘要: Despite plenty of literatures focused on the application of pre-ozonation prior to membrane, it was still unclear about the role of divalent cations (Ca²⁺ and Mg²⁺) in reverse osmosis (RO) membrane fouling mitigation. In this study, ozone pre-treatment (0.10, 0.25 and 0.50 mg O₃/mg DOC (dissolved organic carbon)) was employed to oxidize model biopolymer, which was represented by bovine serum albumin (BSA) and sodium alginate (SA) in the presence of Ca²⁺ and Mg²⁺ (0.5, 1.0 and 2.0 mM). Cross-flow filtration was conducted to investigate RO membrane fouling by concentration mode. The results showed that at appropriate ozone dose there were measurable changes in physicochemical properties of BSA and SA, including increases in particle size, hydrophilicity, density of negative charge and carboxylic groups. Pre-ozonation markedly alleviated RO fouling by BSA at ozone dose of 0.25 mg O₃/mg DOC when Ca²⁺ and Mg²⁺ concentrations raised from 0.5 to 2.0 mM since the increase in electrostatic (EL) repulsion and decrease in hydrophobic (HP) interaction compensated the increase in divalent cation bridging. Similar results were obtained for SA fouling in the presence of Mg²⁺. In contrast, the effect of pre-ozonation on SA fouling strongly depended on the concentration of Ca²⁺. In brief, it mitigated SA fouling at 0.5 mM Ca²⁺, whereas accelerated irreversible fouling at higher Ca²⁺ concentration (1.0 and 2.0 mM) due to the overwhelming effect of divalent cation bridging compared to EL and HP interactions, as revealed by adsorption experiments (in-situ streaming potential measurement). Pre-ozonation shifted the fouling layer from compact to porous and weakened the adhesion forces between foulants and membrane (foulants) except for SA containing 1.0 and 2.0 mM Ca²⁺. This study may provide the guidance for the application of pre-ozonation prior to RO filtration.
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25603. 题目: Aging of biochar-based fertilizers in soil: Effects on phosphorus pools and availability to Urochloa brizantha grass
文章编号: N19123002
期刊: Science of The Total Environment
作者: José Ferreira Lustosa Filho, Jefferson Santana da Silva Carneiro, Cristiane Francisca Barbosa, Kelly Pereira de Lima, Aline do Amaral Leite, Leônidas Carrijo Azevedo Melo
更新时间: 2019-12-30
摘要: Water-soluble phosphate fertilizers release phosphorus (P) to soils promptly, causing P fixation and low plant availability in highly weathered tropical soils. Therefore, the development of strategies to improve P use efficiency is needed. We hypothesized that biochar-based fertilizers (BBFs) can provide available P to plants and improve P use efficiency when compared with soluble fertilizers. Thus, triple superphosphate (TSP) and phosphoric acid (H₃PO₄) were pyrolyzed with and without magnesium oxide (MgO) and poultry litter to produce slow-release P BBFs. A pot experiment under greenhouse conditions was performed to evaluate agronomic efficiency of BBFs compared with TSP in an Oxisol. The treatments were incubated over 100 days after the application of 25, 50, 100, and 200 mg kg⁻¹ of P. Three controls were used, including 200 mg kg⁻¹ of P as TSP incubated for 100 days (named TSP_incubation) and applied immediately before sowing (named TSP_planting) and a negative control (without P). Marandu grass (Urochloa brizantha cv. Marandu) was cultivated in pots for three cycles of 40 days each. After cultivation, a sequential extraction procedure was used to determine the P distribution among different P pools. The shoot dry matter yield in the first cropping cycle was higher at the highest P rate for TSP_planting. PLB-H₃PO₄-MgO showed 9% increase in the shoot dry matter when compared with TSP_incubation in the first cropping cycle. In subsequent cropping cycles, all BBFs promoted higher biomass yield when compared with TSP_planting. There was an increase in the labile and moderately labile P fractions in soil after cultivation with PLB-TSP. The results suggest that BBFs can enhance P use efficiency in tropical soils in the middle- to long-term run due to slow-release profile that prevent P fixation and promote higher residual effect of fertilization.
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25604. 题目: Increased soil pH and dissolved organic matter after a decade of organic fertilizer application mitigates copper and zinc availability despite contamination
文章编号: N19123001
期刊: Science of The Total Environment
作者: Céline Laurent, Matthieu N. Bravin, Olivier Crouzet, Céline Pelosi, Emmanuel Tillard, Philippe Lecomte, Isabelle Lamy
更新时间: 2019-12-30
摘要: Long-term organic fertilizer (OF) application on agricultural soils is known to induce soil Cu and Zn contamination, along with pH and organic matter changes, which in turn alter the soil Cu and Zn availability. Our study was aimed at assessing Cu and Zn availability in long-term OF-amended soils by distinguishing the importance of increased contamination levels versus pH and organic matter changes in soil. Seventy-four soil samples were collected over time from fields corresponding to three soil types upon which no, mineral, or organic fertilization had been applied over a decade, and thus exhibited a gradient of Cu and Zn contamination, pH, and organic matter concentration. Soil Cu and Zn contamination (i.e. total and DTPA-extractable Cu and Zn concentration), soil solution chemistry (i.e. pH and dissolved organic matter concentration and aromaticity) and Cu and Zn availability (i.e. total concentration and free ionic activity in solution and DGT-available concentration in soil) levels were measured. The Windermere humic aqueous model (WHAM) was used to estimate Zn²⁺ activity and dissolved organic matter (DOM) binding properties in soil solution. Regardless of the soil type, organic fertilization increased Cu and Zn contamination in soil, in addition to the pH and the DOM concentration, aromaticity and binding properties in soil solution. The pH increase prompted a decrease in the total Zn concentration and Zn²⁺ activity in soil solution. The concomitant pH increase and DOM concentration, aromaticity and binding properties boosted the total Cu concentration but decreased the Cu²⁺ activity in soil solution. DGT-available Cu and Zn varied very little between the three fertilization modalities. Our results suggest that pH and DOM changes were able to regulate Cu and Zn availability in long-term OF amended soils by exerting a protective effect that offset the concomitant increase in soil Cu and Zn contamination.
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25605. 题目: Fate of organic carbon burial in modern sediment within Yangtze River Estuary
文章编号: N19122911
期刊: Journal of Geophysical Research: Biogeosciences
作者: Xueshi Sun, Dejiang Fan, Huijie Liao, Yuan Tian
更新时间: 2019-12-29
摘要: Large river‐dominated margins play a potential key role in regulating global carbon cycle and budget relative to high terrestrial organic carbon (C_org) inputs and sediment accumulation rates. Here, bulk elements (C_org and TN), isotopic compositions (δ¹³C_org and δ¹⁵N), radioisotope ²¹⁰Pb, sedimentary grain size, pH, Eh, and physicochemical properties were analyzed on samples from the Yangtze River Estuary (YRE) to determine the mechanism involved in transporting sedimentary C_org offshore. In addition, nine box‐cores were analyzed to further reveal the potential effects of the declining sediment load on the modern depositional pattern of C_org. The statistical analyses indicate that the hydrodynamically‐driven sediment composition exerts a significant control on the transport, mobilization, and accumulation of sedimentary C_org from the river to the estuary, with respect to the redistribution of fine‐grained sediments. Furthermore, X‐radiographs and ²¹⁰Pb indicate that reworked environment dominates carbon burial in the Yangtze proximal deposit, while a stable sedimentary environment of C_org (3.50−5.58 g cm^‐2 yr^‐1) is observed in the Yangtze distal mud. Notably, the enhanced erosional inputs that contain terrestrial plant debris (mainly the coarse fractions), have tended to become important sources for C_org. Although reworked sediments in YRE are frequently exposed to oxygen during physical and biological processes, there appears to be a high potential for long‐term sedimentary C_org storage, due to its association with sediment particles (mainly the clay fractions) that provide physical protection against its degradation.

25606. 题目: Polyethyleneimine-modified biochar for enhanced phosphate adsorption
文章编号: N19122910
期刊: Environmental Science and Pollution Research
作者: Tiantian Li, Zhaohui Tong, Bin Gao, Yuncong C. Li, Ashley Smyth, Haimanote K. Bayabil
更新时间: 2019-12-29
摘要: Biochar, a low-cost porous carbonaceous adsorbent, has low adsorption capacity for anion contaminants. The objective of this study was to improve biochar’s ability to adsorb phosphorus (P) through polyethyleneimine (PEI) modification to form an amine-functionalized biochar. Biochars prepared by pyrolysis of bamboo biomass, before and after PEI modification, were characterized using the Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), elemental analysis, and batch sorption experiments. The effects of pH, coexisting anions, and ionic strength on P adsorption by PEI-modified biochar were also investigated. Results indicated that PEI was successfully grafted onto biochar which resulted an increase in surface amine group and in P adsorption. The peak of P adsorption occurred at pH of three and adsorption of P was decreased with increasing of ionic strength and when coexisting ions, such as HCO₃⁻, SO₄²⁻, NO₃⁻, and Cl⁻, were coexisted. The electrostatic interaction between P and surface functional groups of PEI-modified biochar served as the primary mechanism controlling the adsorption process. These results indicate that chemically functionalized biochar with amine groups can enhance P adsorption.

25607. 题目: Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution
文章编号: N19122909
期刊: Environmental Science and Pollution Research
作者: Afrouz Bagheri, Emmanuel Abu-Danso, Jibran Iqbal, Amit Bhatnagar
更新时间: 2019-12-29
摘要: In this study, Moringa seed powder (M_SP) was pyrolyzed at 450 °C to synthesize Moringa seed powder biochar (M_SPB) and treated with phosphoric acid (H₃PO₄) to synthesize phosphate-modified Moringa seed powder biochar (M_SPB-HPO) as an adsorbent for the removal of diclofenac (Dfc) from aqueous solution. Fourier transform infrared (FTIR) analysis, energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and pH point of zero charge (pH_pzc) were conducted to give more insight into the adsorbent’s properties. The SEM analysis showed the transformations in the surface morphology from the parent material to the synthesized materials after the thermal and acid treatment. EDS analysis revealed the variation in the elemental composition of the materials prior to and after adsorption of Dfc ions. The FTIR analysis showed changes and peak intensities of functional groups involved in Dfc removal. The pH_pzc showed the charge carried by M_SPB-HPO in different pH conditions. Isotherm data best matched the Sips model, and the pseudo-second-order model best described the adsorption kinetics. The maximum adsorption capacity of M_SPB-HPO by Sips model was found to be 100.876 mg g⁻¹.

25608. 题目: Effects of multiple antibiotics on greenhouse gas and ammonia emissions during swine manure composting
文章编号: N19122908
期刊: Environmental Science and Pollution Research
作者: Zhiqiang Chen, Yiqi Wu, Qinxue Wen, Hongwei Ni, Chunrong Chai
更新时间: 2019-12-29
摘要: Antibiotics are commonly used in intensive farming, leading to multiple antibiotic residue in livestock waste. However, the effects of multiple antibiotics on the emissions of greenhouse gas and ammonia remain indistinct. This paper selects sulfamethoxazole and norfloxacin to represent two different types of antibiotics to explore their effects on gaseous emissions. Four treatments including CK (control), SMZ (spiked with 5 mg kg⁻¹ DW sulfamethoxazole), NOR (spiked with 5 mg kg⁻¹ DW norfloxacin), and SN (spiked with 5 mg kg⁻¹ DW sulfamethoxazole and 5 mg kg⁻¹ DW norfloxacin) were composted for 65 days. Coexistence of sulfamethoxazole and norfloxacin facilitated the biodegradation of organic carbon, and significantly (p < 0.05) increased the cumulative CO₂ emission by 31.9%. The cumulative CH₄ emissions were decreased by 6.19%, 23.7%, and 27.6% for SMZ, NOR, and SN, respectively. The total NH₃ volatilization in SMZ and NOR rose to 1020 and 1190 mg kg⁻¹ DW, respectively. The individual existence of sulfamethoxazole significantly (p < 0.05) ascended the N₂O emission rate in the first 7 days due to the increase of NO₂⁻-N content. In addition, coexistence of sulfamethoxazole and norfloxacin notably dropped the total greenhouse gas emission (subtracting CO₂) by 15.5%.

25609. 题目: Influence of late-Holocene climate change on the solid-phase speciation and long-term stability of arsenic in sub-Arctic lake sediments
文章编号: N19122907
期刊: Science of The Total Environment
作者: Clare B. Miller, Michael B. Parsons, Heather E. Jamieson, Omid H. Ardakani, Braden R.B. Gregory, Jennifer M. Galloway
更新时间: 2019-12-29
摘要: Sediment cores were collected from two lakes in the Courageous Lake Greenstone Belt (CLGB), central Northwest Territories, Canada, to examine the influence of late-Holocene warming on the transport and fate of arsenic (As) in sub-Arctic lakes. In both lakes, allochthonous As-bearing minerals (i.e. arsenopyrite and scorodite) were identified in sediment deposited during times of both regional warming and cooling, suggesting that weathering of bedrock and derived surficial materials provides a continual source of As to lakes of the CLGB. However, maximum porewater As (84 μg·L⁻¹ and 15 μg·L⁻¹) and reactive organic matter (OM; aquatic and terrestrial-derived) concentrations in each lake are coincident with known periods of regional climate warming. It is inferred that increased biological production in surface waters and influx of terrigenous OM led to the release of sedimentary As to porewater through reductive dissolution of As-bearing Fe-(oxy)hydroxides and scorodite during episodes of regional warming. Elevated sedimentary As concentrations (median: 36 mg·kg⁻¹; range: 29 to 49 mg·kg⁻¹) are observed in sediment coeval with the Holocene Thermal Maximum (ca. 5430 ± 110 to 4070 ± 130 cal. years BP); at these depths, authigenic As-bearing framboidal pyrite is the primary host of As in sediment and the influence of organic matter on the precipitation of As-bearing framboidal pyrite is apparent petrographically. These findings suggest that increased biological productivity and weathering of terrestrial OM associated with climate warming influences redox cycles in the near-surface sediment and enhances the mobility of As in northern lakes. Knowledge generated from this study is relevant for predicting future climate change-driven variations in metal(loid) cycling in aquatic systems and can be used to interpret trends in long-term environmental monitoring data at historical, modern, and future metal mines in northern environments.
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25610. 题目: Peroxymonosulfate activation by Co₉S₈@ S and N co‐doped biochar for sulfamethoxazole degradation
文章编号: N19122906
期刊: Chemical Engineering Journal
作者: Shizong Wang, Jianlong Wang
更新时间: 2019-12-29
摘要: High efficient and stable activator is desired for the sulfate radical-based wastewater treatment. Cobalt sulfide and cobalt oxide have high catalytic activity for peroxymonosulfate (PMS), but poor stability. Here, a novel composite, nano Co₉S₈ and CoO encapsulated by nitrogen and sulfur co-doped sludge-derived biochar (CoO/Co₉S₈@N-S-BC) was synthesized, characterized and applied for activating PMS. The results showed that CoO/Co₉S₈@N-S-BC can effectively activate PMS for sulfamethoxazole (SMX) degradation, and 0.08 mM of SMX could be completely degraded within 10 min. The influencing factors, such as pH, temperature, chloridion, carbonate and humic acid were investigated. The SMX degradation conformed to pseudo first-order kinetics with rate constant of 0.379 min⁻¹. Sulfate radicals (dominant) and hydroxyl radicals contributed to SMX degradation. Carbon defects, pyridinic N, quaternary N, the carbon atoms next to pyridinic N, CO groups, -C-S-C and Co(II), all contributed to PMS activation.
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25611. 题目: Cycling and total risks of multiple As fractions in the Beijing–Tianjin–Hebei area on the agricultural plain, China
文章编号: N19122905
期刊: Ecotoxicology and Environmental Safety
作者: Kui Cai, Zefeng Song
更新时间: 2019-12-29
摘要: The high toxicity of As can cause serious health risks for humans; therefore, understanding the behavior of As in weakly alkaline soil conditions relevant to agricultural plains is important. To investigate the mobility and total risks of multiple fractions of As, 230 pairs of soil (including soil cores) and, wheat grain, and corresponding groundwater samples and 38 atmospheric deposition samples were collected from agricultural soil in the Beijing–Tianjin–Hebei region, China, which is a typical wheat-growing area. Seven fractions of As, namely, water-soluble (As1), exchangeable (As2), carbonate-bound (As3), humic acid-bound (As4), Fe–Mn oxide-bound (As5), organic matter-bound (As6), and residual (As7) As, were analyzed using a sequential extraction procedure to better understand and confirm the relationship among these different forms. Correlation and principal components analyses showed a significant relationship among As1–As5, and As in atmospheric deposits and As in groundwater and soil samples showed a positive relationship. As found in wheat, therefore, mainly originated from the soil and atmospheric deposits, and indirectly from the groundwater. As in the soil samples was mainly controlled by Mn and Fe₂O₃ based on the vertical distribution of soil cores and correlation analysis. The health risk assessments showed that As in the multiple fractions did not form a potential non-cancer risk for children and adults. However, residents could still face the risk of developing cancer by ingesting wheat and drinking the groundwater. The findings of this study have important implications for understanding the hydrological/geochemical behavior of As and the soil and water quality in a wide range of environmental settings. Additionally, our findings provided arguments for decreasing the concentrations of As in the wheat production system and to remind residents to decrease ingestion of their staple food (wheat) and drink less of the local groundwater.
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25612. 题目: First report on carbon storage in a warm-temperate mangrove forest in South Africa
文章编号: N19122904
期刊: Estuarine, Coastal and Shelf Science
作者: Jaime L. Johnson, Jacqueline L. Raw, Janine B. Adams
更新时间: 2019-12-29
摘要: Carbon (C) storage by vegetated coastal habitats (mangroves, salt marshes and seagrasses) is globally recognized as a critical ecosystem service. Research efforts have therefore focused on quantifying C stored in these “blue carbon” ecosystems but a notable knowledge gap still exists for certain geographical regions. This study aimed to provide the first comprehensive assessment of C storage in South African warm temperate mangroves by quantifying the C storage in aboveground biomass and soil C pools associated with the mangrove forest at the Nxaxo Estuary. C storage variability was also related to mangrove forest structure and soil environmental variables. C storage was quantified using standardized protocols for aboveground (live trees, leaf litter, pneumatophores) and soil C pools at five Avicennia marina sites. The results showed C storage to be spatially variable as soil C was consistently higher in the upper intertidal zone of each site towards the landward edge of the mangrove. Aboveground C pools were similar between intertidal zones within the sites. The soil C pool made the largest contribution to total C storage at each site and ranged from 176.91 ± 4.5 MgC.ha⁻¹ to 262.53 ± 18.8 MgC.ha⁻¹. Of the aboveground carbon pools, live trees made the largest contribution and ranged from 2.25 ± 1.0 MgC.ha⁻¹ to 9.56 ± 3.6 MgC.ha⁻¹. Across all sites, average C storage for all pools was 234.9 ± 39.16 MgC.ha⁻¹, which falls within the range reported for mangroves at other southern hemisphere range limits. Variability in soil C was linearly related to soil organic matter but this relationship was inconsistent between different soil depth intervals that were sampled. Total C storage was inversely related to mangrove tree density. This study confirms the need for more blue carbon studies to quantify C storage in under-represented geographical areas and to investigate factors that drive variability in C storage at different spatial scales.
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25613. 题目: Altered groundwater discharge and associated carbon fluxes in a wetland-drained coastal canal
文章编号: N19122903
期刊: Estuarine, Coastal and Shelf Science
作者: Kay Davis, Isaac R. Santos, Anita K. Perkins, Jackie R. Webb, Justin Gleeson
更新时间: 2019-12-29
摘要: Residential canal systems are becoming increasingly popular with the rising demand for absolute coastal waterfront properties. We hypothesize that canals alter groundwater-surface water connectivity and related carbon fluxes into coastal surface waters. Here, we quantified submarine groundwater discharge (SGD) in a residential canal system on Bribie Island (Australia) and associated carbon fluxes. SGD rates estimated from a radon (²²²Rn) mass balance model were 3.1 ± 1.5 cm d⁻¹. These fluxes delivered 68 ± 44 and 70 ± 48 mmol m⁻² d⁻¹ of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) into the canal, respectively. Carbon dioxide (CO₂) emissions to the atmosphere ranged from 15 to 28 mmol m⁻² d⁻¹. Multiple lines of evidence, including flux estimates and groundwater observations, converge to the conclusion that SGD was a major source of DOC and free CO₂, but not carbonate alkalinity nor DIC to canal surface waters. In comparison to mangrove tidal creeks that often precede canals, the canal had (1) lower tidally-driven saline groundwater exchange rates but higher fresh groundwater discharge, (2) lower CO₂ emissions to the atmosphere; and (3) acted as a driver rather than a buffer of local ocean acidification. These differences seem to be driven by the replacement of intertidal wetland vegetation with urban areas that prevent soil carbon accumulation and related biogeochemical processes around the canals. We suggest that decisions on canal construction should consider potential changes to groundwater-derived soil carbon losses and carbon cycling in receiving coastal waters.

25614. 题目: Self-engineered iron oxide nanoparticle incorporated on mesoporous biochar derived from textile mill sludge for the removal of an emerging pharmaceutical pollutant
文章编号: N19122902
期刊: Environmental Pollution
作者: Vikash Singh, Vimal Chandra Srivastava
更新时间: 2019-12-29
摘要: In the present work, low-cost and efficient iron oxide nanoparticle incorporated on mesoporous biochar was prepared from effluent treatment plant (ETP) sludge collected from the textile industry. This sludge contains a higher amount of Fe due to the use of ferric chloride as a coagulant in the treatment of wastewater generated during the process. The raw sludge and prepared biochar was extensively examined by various sophisticated techniques like XRF, XRD, BET, TGA, XPS, RAMAN, FTIR, FESEM, TEM, and VSM. TEM and XRD analysis confirms the presence of iron oxide nanoparticles on mesoporous biochar. The prepared biochar was found to possess BET surface area of 91 m² g⁻¹. Several parameters like pH, dose, initial concentration, temperature and time were optimized for the adsorptive removal of ofloxacin (OFL) from aqueous solution. Biochar (named as BTSFe) achieved ≈96% removal efficiency of OFL with a maximum adsorption capacity (q_m) of 19.74 mg g⁻¹ at optimum condition. π-π electron–donor-acceptor and H bonding were the major mechanisms responsible for the OFL adsorption. Kinetic and equilibrium thermodynamic study of showed that the adsorption of OFL was represented by the pseudo-second-order kinetics model, and the process was exothermic and spontaneous. Additionally, Redlich-Peterson and Freundlich isotherms best fitted the experimental data indicating multilayer adsorption phenomenon. Biochar was magnetically separated and thermally regenerated after each cycle for five times with a nominal overall decrease of ≈8% in removal efficiency. Leaching of iron during the adsorption process was also checked and found to be within the permissible limit. This study provides an alternative application of the textile industry sludge as an efficient, low-cost biochar for the removal of emerging pharmaceutical compounds.
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25615. 题目: A comparison of n-alkane contents in sediments of five lakes from contrasting environments
文章编号: N19122901
期刊: Organic Geochemistry
作者: Yongdong Zhang, Jinlei Yu, Yaling Su, Yingxun Du, Zhengwen Liu
更新时间: 2019-12-29
摘要: In paleolimnology studies, the trajectories of n-alkane abundances and distributions in dated sediments are widely used indicators of changing environmental and ecological status in the overlying water over time. However, the factors contributing to the variable n-alkane profiles of lake systems are not yet fully understood. Here, a comparative study was conducted to examine natural and anthropogenic influences on the sediment n-alkane profiles of five representative lakes in China. Core samples from the deep oligo- mesotrophic lakes Fuxian and Lugu (FX-1 and LG-1 cores), the shallow eutrophic lakes Taibai and Changdang (TB-1 and CD-1 cores) and the alpine Lake Heihai (HH-1 core) were used. While there were striking differences in n-alkane abundances and distributions between the cores, the results suggested that the n-alkanes in all five studied lakes were derived mainly from biogenic sources, rather than from petroleum contamination. The short-chain (<C₂₀) even carbon n-alkanes, assumed to derive from non-photosynthetic bacteria, were especially prevalent in FX-1, reaching 158.3–284.4 μg/g TOC, which might be a result of high levels of bacterial productivity in the deep (average 89.6 m) water column of Lake Fuxian. The contribution of bacterial production diminished in the other four lakes, with <C₂₀ n-alkanes declining to between 21.4 and 60.5 μg/g TOC on average in the studied cores. In the two shallow lakes, abundances of short-chain (<C₂₀) odd carbon n-alkanes were greatly elevated in sediments corresponding to the eutrophic phase; for example, with maximum values of 136.3 μg/g TOC recorded in TB-1. This nutrient-driven effect was less apparent in deep lakes. The >C₂₁ n-alkane profiles of different cores varied significantly. Abundances of long-chain n-alkanes (C₂₉, C₃₁ and C₃₃) in HH-1 were approximately 3–7 times greater than in other cores. Coupled with the lowest Paq (average 0.29) values recorded in the study, this indicates a predominantly terrestrial plant origin for the >C₂₁ n-alkanes, most likely the dense alpine meadow which surrounds the lake. In other cores, however, aquatic macrophytes appear to be more important contributors of the n-alkanes, a result that corresponds with the relatively low density of terrestrial plants in those catchments.

25616. 题目: Screening the main factors affecting phthalate esters adsorption on soils, humic acid, and clay organo-mineral complexes
文章编号: N19122819
期刊: Ecotoxicology and Environmental Safety
作者: Chao Xue, Liang Peng, Jinping Tang, Ming Lei, Anwei Chen, Jihai Shao, Si Luo, Yunsong Mu
更新时间: 2019-12-28
摘要: Phthalate esters (PAEs) are one of the most frequently detected organic pollutants in soils. In this work, the adsorption behaviors of di-ethyl phthalate (DEP) and dibutyl phthalate (DBP) on soils, humins (HM) and Clay organo-mineral complexes (Clay-OM) from four regions in China, Changchun (CC), Cangzhou (CZ), Yinchuan (YC), and Changsha (CS) were studied. The surface and structural properties of these sorbents were characterized using Brunauer-Emmett-Teller specific surface area, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and ¹³C nuclear magnetic resonance methods. The results showed that the CC soil has the largest pore volume (PV) and specific surface area (SSA). PV, SSA, and aliphatic carbon content of the samples ranked as Clay-OM > HM > soil. Adsorption experiments indicated that the Clay-OM exhibited the strongest adsorption affinity for both DBP and DEP, followed by HM, and then the soil samples. Furthermore, DEP and DBP adsorption amounts on the samples declined as follows: CC > CS > CZ > YC. To illustrate the dominant mechanisms for PAEs adsorption onto soil, the soil organic carbon content normalized adsorption coefficient (LogK_oc) was correlated with several possible parameters using multiple parameter linear regression and significance testing. The R² values of the DBP and DEP in multi-regression equations were 0.825 and 0.741 respectively, and the significance test suggested that pore structure and specific surface area had crucial influences on the adsorption progress.

25617. 题目: Exposure to polyamide 66 microplastic leads to effects performance and microbial community structure of aerobic granular sludge
文章编号: N19122818
期刊: Ecotoxicology and Environmental Safety
作者: Lijian Zhao, Chengyuan Su, Weihong Liu, Ronghua Qin, Linqin Tang, Xue Deng, Shumin Wu, Menglin Chen
更新时间: 2019-12-28
摘要: Microplastic polyamide 66 (PA66) was used to explore its mechanism of influence on the contaminants removal from aerobic granular sludge (AGS) and the corresponding change to the microbial community. Results showed that the removal pollution efficiency of the experimental groups with PA66 were inhibited during the early treatment stage. However, as the experiment progressed, the removal efficiencies of chemical oxygen demand (COD) (92.66%, 93.10%, 93.11%, 93.79%) and ammonia nitrogen (94.25%, 94.58%, 95.61%, 94.73%) were similar in the addition 0 g/L (A), 0.1 g/L (B), 0.2 g/L (C) and 0.5 g/L (D) PA66 beakers at the last 10 days. On the first day, the intensity of fluorescence peaks representing tryptophan protein-like and aromatic protein-like substances of loosely-bound extracellular polymeric substances (LB-EPS) indicated that the PA66 microplastic caused damage to the sludge structure, and the intensity of fluorescence peaks representing fulvic acid-like and humic acid-like substances were stronger than those in the control beaker (A). Microbial community analysis showed that the main phyla were Firmicutes (49.11%, 59.77%, 44.33%, 41.21%), Proteobacteria (26.44%, 11.96%, 31.44%, 19.4%) and Bacteroidetes (9.24%, 13.05%, 11.89%, 14.71%) in the four beakers. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, genes representing [T] Signal transduction mechanisms illustrated that adding PA66 microplastic resulted in more signaling molecules in the AGS.
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25618. 题目: Characteristic of adsorption, desorption, and co-transport of vanadium on humic acid colloid
文章编号: N19122817
期刊: Ecotoxicology and Environmental Safety
作者: Li Chen, Yan-yuan Zhu, Hou-qiao Luo, Jin-yan Yang
更新时间: 2019-12-28
摘要: Understanding the interactions between humic acid colloid (HAC) and vanadium (V) in soils is of great importance in forecasting the behaviors and fates of V in the soil and groundwater systems. This study investigated the characteristics and factors that affect V adsorption-desorption by the HAC; meanwhile, we also explored the co-transport of the HAC and V in a saturated porous media. Scanning Electronic Microscopy micrographs showed the variation of morphological features on the surface of the HAC before and after V adsorption. Fourier transform infrared spectroscopy spectra revealed that the presence of hydroxyl, carboxyl, carbonyl, carbon-carbon double bond, amino, and aromatic ring on the HAC participated in V adsorption. The adsorption isotherms were well described by the Langmuir model, and the adsorption kinetics of the HAC was better described by the pseudo-first-order kinetic models. The adsorption-desorption was strongly dependent on the initial V concentration, solution pH, and temperature. The maximum adsorption amount was 861.17 mg g⁻¹ by 200 mg L⁻¹ HAC at the initial V concentration of 500 mg L⁻¹, and the corresponding desorption amount was 15.13 mg g⁻¹. These results showed that the HAC had high fixation capacity of V in soil. In addition, the HAC sped up the mobility of V; however, it decreased mass of migration of V in the saturated quartz sand column. These results are expected to provide insight into the potential impact of HAC on geochemical behaviours of V in vulnerable ecosystems.

25619. 题目: Does edge erosion alter coastal wetland soil properties? A multi-method biogeochemical study
文章编号: N19122816
期刊: CATENA
作者: Havalend E. Steinmuller, Michael P. Hayes, Nia R. Hurst, Yadav Sapkota, Robert L. Cook, John R. White, Zuo Xue, Lisa G. Chambers
更新时间: 2019-12-28
摘要: Coastal wetlands in Louisiana experience high rates of edge erosion due to combined eustatic sea level rise and coastal subsidence. This study sought to (1) evaluate site-specific spatial and temporal patterns in marsh edge erosion rates within Barataria Bay, LA, (2) develop an understanding of the physical and chemical properties of eroding soils through biogeochemical and spectroscopic characterization, and (3) evaluate interactions between erosion, saltwater incursion, and soil properties through a comparison of sites with different erosion rates and varying distances from the eroding edge. Replicate soil cores were collected at three distances inland (1 m, 3 m, 5 m) at three different sites (west, south, and north) to a depth of 1 m. Erosion rates were measured at each site, and soils were sectioned into 10 cm intervals for a total of 270 soil and porewater samples. Each soil sample was subjected to soil physicochemical analysis (bulk density, moisture content, organic matter content, and total carbon (C), nitrogen (N), and phosphorus (P)) as well as assessments of biogeochemical cycling (production of CO₂, mineralization of N and P, and extractable nutrient concentrations). Porewater samples were analyzed to elucidate spectroscopic and fluorometric indicators of carbon quality (aromaticity, humification, lignin proportion, and C source). Erosion rates at the west, north, and south sites were 3.36 ± 0.4, 1.34 ± 0.2, and 0.58 ± 0.03 m yr⁻¹, respectively. Neither erosional magnitude nor saltwater incursion was found to be significant predictors of any measured spectroscopic or biogeochemical parameters, though depth was a significant control on 18 of the measured 20 parameters. The top 30 cm were more biologically active (as indicated by greater mineralization of C, N and P) and were characterized by lower molecular weight porewater DOM with less aromaticity. Degree of humification and aromaticity of porewater DOM increased with both depth and distance inland. Concentrations of bioavailable N and P at 1 m depth were at least 5 times greater than surface concentrations, representing a pool of nutrients that could be exported into the coastal ocean with ongoing erosion. This study is the first to couple spectroscopic and biogeochemical measurements for the purpose of assessing soil and porewater physicochemistry within wetland soils and illustrates an as-yet unaccounted for potential for the export of labile C, N, and P into the coastal ocean.

25620. 题目: Predicting soil aggregate stability using readily available soil properties and machine learning techniques
文章编号: N19122815
期刊: CATENA
作者: Javier I. Rivera, Carlos A. Bonilla
更新时间: 2019-12-28
摘要: Aggregate stability is a measurement of soil quality, as the presence of stable aggregates relates to a wide range of soil ecosystem services. However, aggregates stability is not reported in most soil surveys, so predictive models have been focus of increasing attention as an alternative method in the absence of direct measurements. Therefore, the objective of this study was to develop a new model for predicting aggregate stability, using two machine learning techniques: An Artificial Neural Network (ANN) model and Generalized Linear Model (GLM). These techniques were applied to a soil dataset described in terms of soil texture, organic matter content, pH, and water-stable aggregates. This dataset included 109 soil samples obtained at 0–17 cm soil depth from hyperarid, arid, semiarid, and humid regions in Chile, including agricultural soils, shrubland, and forestland. Most soil textures in this dataset were sandy loam, loam, and clay loam, and each soil property had a large range of values. Aggregate stability was measured and computed as the percentage of water-stable aggregates using a wet sieving apparatus, and the ANN and GLM models were constructed and evaluated by repeated cross-validation (80% and 20% of dataset for training and testing, respectively). The ANN and GLM models were compared by computing the modified r² (radj2, Root Mean Square Error (RMSE), and Mean Absolute Error (MAE). The results demonstrated a positive gradient of aggregate stability from arid (40% in average) to humid (87% in average) regions, which is related to the increase in organic matter content and decrease in pH. Organic matter content and pH exhibited a significant correlation to the aggregate stability, with r = 0.56 and r = −0.73, respectively. Moreover, among the fractions used to compute the soil texture, the clay content exhibited the highest correlation with aggregate stability (r = 0.30). These variables were used for training and testing the ANN and GLM models. The ANN model achieved superior performance in terms of the RMSE, radj2 and MAE in the cross-validation procedure, and showed r² = 0.80 for training and r² = 0.82 for testing. The GLM yielded r² = 0.59 and r² = 0.63 for training and testing, respectively. Therefore, despite the limitations observed when implementing ANN, its use is recommended instead of GLM as a reference model. Considering the small number of easily measured variables, this study provides two models that can be coupled with other existing soil routines or can be used directly to complete soil surveys where the aggregate stability was not measured.
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