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23581. 题目: Biochar as simultaneous shelter, adsorbent, pH buffer, and substrate of Pseudomonas citronellolis to promote biodegradation of high concentrations of phenol in wastewater
文章编号: N20011102
期刊: Water Research
作者: Ling Zhao, Donglin Xiao, Yang Liu, Huacheng Xu, Hongyan Nan, Deping Li, Yue Kan, Xinde Cao
更新时间: 2020-01-11
摘要: Microbial degradation is an elimination method for removal of organic contaminants from soil and water. However, the main factor limiting its practical application is high bacterial sensitivity to environmental factors such as pH, toxicity, and mass transfer. In this study, biochar was produced pyrolytically from peanut shells at 350 °C, 550 °C, and 750 °C (referred to as BC350, BC550, and BC750, respectively) and their promotion on phenol biodegradation in wastewater by the bacterium Pseudomonas citronellolis was investigated. Higher initial phenol concentration (>400 mg L⁻¹) showed obvious inhibition on biodegradation with the removal efficiencies being less than 46%, and even the bacterium failed to survive at the phenol concentrations of higher than 1000 mg L⁻¹. With biochar incorporated, the removal efficiencies of phenol increased from below 46% to up to 99% at the initial concentrations of 400–1200 mg L⁻¹. Immobilization of strains in biochar by calcium alginate further increased the microbial tolerance to high concentrations of phenol (i.e., 63% removal at 1200 mg L⁻¹). Scanning electron microscopy demonstrated that biochar acted as shelter to support the bacterium to struggle with extreme conditions. The initial adsorption of phenol by biochar alleviated the initial toxicity of phenol to bacterium and the subsequent gradual desorption controlled the bioavailability of phenol. In this regard, BC350 showed a comparable sorption capacity with BC550 and BC750, while a higher desorption potential than them, thus balanced better the toxicity and bioavailability of phenol to microbes. Alkalinity of BC550 and BC750 played important roles in rescuing the microbes from being damaged by pH shock via neutralizing the fast generation of acidic intermediates. The extractable organic substances in BC350 could be consumed by bacterium as substrates, which was confirmed by incubating the strains in water-extractable solution. Results of this study indicate that incorporation of microbes with biochar could promote the biodegradation of high concentration organic wastewater.
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23582. 题目: Regional-scale investigation of dissolved organic matter and lead binding in a large impacted lake with a focus on environmental risk assessment
文章编号: N20011101
期刊: Water Research
作者: Xiaokai Zhang, Boling Li, Jianming Deng, Boqiang Qin, Mona Wells, Boris Tefsen
更新时间: 2020-01-11
摘要: Environmental risk assessment (ERA) increasingly relies on speciation modeling of bioavailability. Heavy metals are the most prevalent pollutants globally, and dissolved organic matter (DOM) plays an important role in speciation and bioavailability of heavy metals. Due to the variation of DOM properties in natural aquatic systems, improvements to the standard one-size-fits-all approach to modeling metal-DOM interactions are needed for ERA. In this study, we investigate variations in DOM and lead (Pb)-DOM binding in Lake Tai (Taihu), a large, impacted lake in eastern China that is characterized by a complex drainage network and is an important water resource at a regional level, and we assess implications of our findings within the context of ERA needs. In our study, DOM in water samples collected from across the 2400 km² area of Taihu was characterized using three-dimensional excitation emission matrix and synchronous fluorescence spectroscopy spectra, the latter being used to calculate conditional stability constants for metal binding. Parallel factor analysis and peak picking were used to assess contributions of protein- and humic-like components of DOM, and fluorescence indices indicative of diagenetic processes were calculated. These quantities calculated from spectroscopic studies, in addition to water quality parameters, were analyzed by bivariate and multivariate analysis. Results show that different DOM components are highly variable across different regions of Taihu, and bivariate and multivariate analyses confirm that water quality and DOM characterization parameters are strongly interrelated. This reflects the different inputs, diagenetic and transport processes across the large expanse of Taihu. We find that the conditional stability constant of Pb-DOM binding is strongly affected by the water chemical properties and composition of DOM, though DOM is not itself a parameter that differentiates lake water properties in different regions of the lake. The variability of DOM composition and Pb-DOM binding strength across Taihu is consistent with prior findings that a one-size-fits-all approach to metal-DOM binding may lead to inaccuracies in commonly used speciation models, and therefore such generalized approaches need improvement for regional-level ERA in complex watersheds. The approach taken here to obtain site-specific metal-DOM conditional stability constants for use in increasing the accuracy of speciation modeling is fit-for-purpose for ERA applications at regional levels because the approach is relatively simple, inexpensive, and amenable to high throughput analysis.
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23583. 题目: Long-term changes in organic matter stocks and quality in an Oxisol under intensive vegetable cultivation
文章编号: N20011008
期刊: CATENA
作者: Karolline S. Figuerêdo, Marcel T.J. Pereira, Carlos Nick, Ivo R. Silva, Teogenes S. Oliveira
更新时间: 2020-01-10
摘要: Changes in carbon (C) and nitrogen (N) reserves reflect the impacts of land use and management. The objective was to evaluate the changes in organic matter stocks and quality in an Oxisol under intensive vegetable cultivation in the Brazilian Cerrado region. Four areas were selected: one under Cerrado vegetation (CV) and three under vegetable production with 15 (VG₁₅), 20 (VG₂₀) and 30 (VG₃₀) years of cultivation. Soil samples were collected for the determination of total C (TC) and total N (TN) in soil organic matter fractions and the biochemical composition of particulate organic matter (POM) and mineral-associated organic matter (MOM). The smallest C stocks were observed on VG₃₀, whereas the CV area had the highest values. The TN stocks were similar across treatments. The levels of labile C decreased with cultivation time. Increases and reductions in carbohydrate and lignin ratios in POM and MOM occurred in VG₁₅ and VG₂₀, respectively, with POM being more sensitive to changes in land use. There was greater similarity between VG₁₅ and VG₂₀, but differences between CV and VG₃₀. There was a correlation between higher labile reserves (labile C and carbohydrates) and areas with shorter land use and between C_mic and agricultural use for 30 years. There was also a negative correlation between soil nutrients and the total and MOM C and N contents as well as the MOM carbohydrate levels, and there was also a negative correlation between C_mic and TC. The intensive use of Oxisols promoted a reduction in soil organic matter stocks and altered their quality.

23584. 题目: Bacterial foraging facilitates aggregation of Chlamydomonas microsphaera in an organic carbon source-limited aquatic environment
文章编号: N20011007
期刊: Environmental Pollution
作者: Ranran Zhao, Guowei Chen, Li Liu, Wei Zhang, Yifei Sun, Baoguo Li, Gang Wang
更新时间: 2020-01-10
摘要: Microalgal aggregation is a key to many ecosystem functions in aquatic environments. Yet mechanistic understanding of microalgae aggregation, especially the interactions with ubiquitous bacteria populations, remains elusive. We reported an experimental study illustrating how the emerging bacterial populations interacted with a model microalga (Chlamydomonas microsphaera) cells and the consequent aggregation patterns. Results showed that the emergence of bacterial populations significantly stimulated C. microsphaera aggregation. Both bacterial and C. microsphaera motilities were remarkably excited upon coculturing, with the mean cell velocity being up to 2.67 and 1.80 times of those of separate bacterial and C. microsphaera cultures, respectively. The stimulated bacterial and C. microsphaera cell velocity upon coculturing would likely provide a mechanism for enhanced probability of cell-cell collisions that led to amplified aggregation of C. microsphaera population. Correlation analysis revealed that bacterial resource foraging (for polysaccharides) was likely a candidate mechanism for stimulated cell motility in an organic carbon source-limited environment, whereby C. microsphaera-derived polysaccharides serve as the sole organic carbon source for heterotrophic bacteria which in turns facilitates bacteria-C. microsphaera aggregation. Additional analysis showed that bacterial populations capable of successive decomposing algal-derived organic matters dominated the cocultures, with the top five abundant genera of Brevundimonas (24.78%), Shinella (17.94%), Sphingopyxis (11.62%), Dongia (5.82%) and Hyphomicrobium (5.45%). These findings provide new insights into full understanding of microalgae-bacteria interactions and consequent microbial aggregation characteristics in aquatic ecosystems.
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23585. 题目: Iron uptake kinetics by coastal micro- and macro-algae in relation to riverine and coastal organic matter
文章编号: N20011006
期刊: Estuarine, Coastal and Shelf Science
作者: Masafumi Natsuike, Yuta Endo, Hiroaki Ito, Manami Miyamoto, Chihiro Yoshimura, Manabu Fujii
更新时间: 2020-01-10
摘要: Iron (Fe) uptake kinetics by the coastal micro-algae Skeletonema marinoi-dohrnii and the macro-algae Eisenia bicyclis were investigated in the presence of Fe and dissolved organic matter (DOM) originating from terrestrial (mountainous rivers) and coastal bay water in northeast Japan. In addition, a synthetic chelator, ethylenediaminetetraacetic acid, was tested as a representative Fe-binding organic ligand with a high Fe affinity. ⁵⁹Fe uptake assays showed a linear relationship between dissolved Fe concentration and Fe uptake rate by both algae at dissolved Fe concentrations ranging from 1.0 nM to 120 nM, indicating that the Fe uptake rate was limited by the concentration of Fe species. Between 8 and 69% of the Fe fraction remained as dissolved forms when river water samples were mixed with seawater. These dissolved forms were ascribed to fulvic-like components. The uptake rate of dissolved Fe originating from river water was slower than that from coastal water (i.e., ∼1.94 and ∼0.43 log for S. marinoi-dohrnii and E. bicyclis, respectively) when the same dissolved Fe concentration was compared. Thus, dissolved Fe in river water may be less bioavailable, and the Fe-binding ligand exchange from exogenous to autochthonous DOM may increase bioavailability in coastal seawater. Excitation-emission matrix-parallel factor analysis, DOC measurements, and Fe uptake tests under dark/light incubation with a Fe(II) scavenging agent indicated differences in dominant Fe uptake mechanisms between DOMs originating in river and bay samples, with photochemical reactions greatly contributing to uptake from riverine Fe-DOM and non-chromophoric DOM produced in marine environments playing an important role in coastal seawater.
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23586. 题目: Pillared graphene oxide composite as an adsorbent of soluble hydrocarbons in water: pH and organic matter effects
文章编号: N20011005
期刊: Journal of Environmental Management
作者: C.E. Flores-Chaparro, C.J. Castilho, I. Külaots, Robert H. Hurt, J.R. Rangel-Mendez
更新时间: 2020-01-10
摘要: Graphene oxide (GO) is a single-atom-thick sheet of carbon with oxygen-containing functional groups decorating its basal plane and edge sites. Most of its high surface area can be lost due to restacking of individual layers during the synthesis and drying of GO-based bulk sorbents. There is great interest to increase the specific surface area of graphene-based sorbents by introducing organic molecules as “pillaring agents” between GO sheets to hinder the stacking process and create sorbents with elevated surface area. This work synthesizes pillared GO by introducing chitosan (CS), a linear polysaccharide with various molecular weights. A composite of low molecular weight CS at a CS/GO ratio of 0.1 is shown to have the highest specific surface area (up to 70.5 m²/g) in comparison to the medium and high CS molecular weight, pristine GO, and the CS/GO composite materials. The affinity of the optimized GO/CS composites towards benzene, toluene, and naphthalene was evaluated at 19.3 mg/L of organic matter content while altering pH. Sips and Langmuir adsorption isotherm models well described the adsorption behavior, and benzene adsorption performance was reduced at low pH. Related to the presence of dissolved organic matter (DOM) in solution, lower diffusivity constants (k₁) in hydrocarbon systems were recorded. Our results demonstrate the feasibility of CS as a potential pillaring agent in CS/GO composites to increase specific surface area and enhance the capture of soluble hydrocarbons from aqueous solutions.
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23587. 题目: Variations in sediment production of dissolved iron across a continental margin not dominated by major upwelling or riverine inputs
文章编号: N20011004
期刊: Marine Chemistry
作者: Eryn M. Eitel, Shannon M. Owings, Keaton M. Belli, Jordon S. Beckler, Anna Williams, Benjamin P. Fields, Malory Brown, Joel Craig, Olivia Bailey Studebaker, Donald B. Nuzzio, Martial Taillefert
更新时间: 2020-01-10
摘要: Despite the undeniable effect of iron on shaping patterns of ocean productivity, the relative importance of the different sources of this limiting nutrient to the ocean is still under debate. Although global estimates indicate that the benthic input of iron to the oceans is significant, most studies have investigated continental margins exposed to either upwelling or large riverine inputs, environments that are not representative of the majority of the oceans. Additionally, the number of studies that report dissolved iron concentrations in continental slope sediments is limited, despite the fact that these regions between the shelf edge and the continental rise make up >5% of the sedimentary surface area of the global ocean. The sedimentary flux of iron has traditionally been considered negligible due to the rapid oxidation of Fe²⁺ in oxic waters and poor solubility of the Fe(III) product. The recent realization that ferric iron may be stabilized in solution by organic ligands during oxidation near the sediment-water interface suggests that a significant fraction of the dissolved iron pool may be present under the form organic-Fe(III) complexes that could eventually reach the overlying waters. In this study, the speciation and biogeochemical importance of iron was determined in intact sediment cores along a transect across the entire continental margin near Cape Lookout, North Carolina, a region not dominated by upwelling or riverine inputs that is representative of most passive continental margins. Rates of diffusive oxygen uptake (DOU) and maximum diffusive fluxes of both dissolved Fe²⁺and organic-Fe(III) complexes decreased from the coastal zone to the continental shelf, remained low on the shelf and the upper continental slope, but rebounded to reach a maximum in mid-slope sediments where concentrations of Fe(III) oxides were the highest along the transect. In turn, DOU decreased and dissolved iron was below detection in lower-slope sediments, indicating that mid-slope sediments represent depocenters where Fe(III) oxides and organic matter may accumulate. Pore water sulfate and sulfide concentrations as well as separate sediment incubations confirmed that sulfate reduction does not greatly influence the cycling of iron in these sediments. The production of dissolved organic-Fe(III) in these continental margin sediments is likely regulated by a combination of aerobic oxidation in the presence of natural organic ligands near the sediment-water interface, dissimilatory iron reduction, or chemical oxidation of Fe(II) complexed to natural organic ligands. Fluxes of Fe²⁺ and organic-Fe(III) complexes across the sediment-water interface were not observed. However, diffusive fluxes of Fe²⁺ and organic-Fe(III) complexes into the oxic zone of these sediments (<1 cm from the sediment-water interface) and production of dissolved Fe(III) in sediment slurry incubations suggest that complexation of Fe(III) in these sediments may contribute to the stabilization and potential transport of dissolved iron into oxygenated deep ocean waters. Extrapolation to the global ocean suggests that mid-slope depocenters contribute considerably to the iron inventory of the ocean, thus warranting the need for measurement of benthic iron fluxes and dissolved iron speciation in these environments.

23588. 题目: Assisted phytoremediation of a former mine soil using biochar and iron sulphate: Effects on As soil immobilization and accumulation in three Salicaceae species
文章编号: N20011003
期刊: Science of The Total Environment
作者: Melissa Simiele, Manhattan Lebrun, Florie Miard, Dalila Trupiano, Philippe Poupart, Olivier Forestier, Gabriella S. Scippa, Sylvain Bourgerie, Domenico Morabito
更新时间: 2020-01-10
摘要: Metal(loid) accumulation in soils, is of increasing concern because of the potential human health risks. Therefore, metal(loid) contaminated sites need rehabilitation. It is becoming increasingly popular to use phytoremediation methods for the reclamation of sites containing metal(loid)s. However, plant establishment and growth on contaminated soils can be difficult due to high metal(loid) concentrations and poor fertility conditions. Consequently, amendments, like biochar and iron sulphate, must be applied. Biochar, obtained from plant biomass or animal wastes pyrolyzed under minimal oxygen supply, showed beneficial effects on soil properties and plant growth. Iron sulphate can effectively immobilize anions, thus mitigating metal(loid) toxicity and hence promoting plant development. This study aimed to assess the effect of two different modalities of biochar amendment application (top third of the tube and all tube height) combined with iron sulphate addition on the physico-chemical properties of a mining polluted soil and the growth and metal(loid) uptake of three Salicaceae species. A 1.5 year mesocosm experiment under field condition was conducted using a former tin mine contaminated by arsenic, amended with biochar and iron sulphate and vegetated with three Salicaceae species. Results showed that the combination of biochar and iron sulphate improved soil characteristics by increasing pH and electrical conductivity and reducing soil pore water metal(loid) concentrations. Between the two biochar application methods, the addition of biochar on the all tube height showed better results. But for such contaminated soil, biochar, in combination with iron sulphate, had no positive effect on plant growth, for all species tested and especially when incorporating on the top third of the tube. Finally, S. purpurea presented high root metal(loid) concentrations associated to the better growth compared to P. euramericana and S. viminalis, making it a better candidate for phytostabilization of the studied soil.
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23589. 题目: Influence of dissolved organic matter on the removal of 12 organic micropollutants from wastewater effluent by powdered activated carbon adsorption
文章编号: N20011002
期刊: Water Research
作者: Ronan Guillossou, Julien Le Roux, Romain Mailler, Caroline Soares Pereira-Derome, Gilles Varrault, Adèle Bressy, Emmanuelle Vulliet, Catherine Morlay, Fabrice Nauleau, Vincent Rocher, Johnny Gasperi
更新时间: 2020-01-10
摘要: The presence of dissolved organic matter (DOM) in wastewater effluents is recognized as the main factor limiting the adsorption of organic micropollutants (OMPs) onto activated carbon. The degree of the negative effect that DOM, depending on its quality, exerts on OMPs adsorption is still unclear. The influence of the interactions between DOM and OMPs on their removal is also not fully understood. Adsorption isotherms and conventional batch tests were performed in ultra-pure water and in wastewater effluent to study the influence of DOM on the adsorption of 12 OMPs onto powdered activated carbon. Best fit of adsorption pseudo-isotherms was obtained with the Freundlich equation and showed, as expected, that OMPs adsorption was higher in ultra-pure water than in wastewater effluent due to the presence of DOM leading to pore blockage and competition for adsorption sites. LC-OCD analysis revealed that biopolymers and hydrophobic molecules were the most adsorbed fractions while humic acids were not removed after a contact time of either 30 min or 72 h. The presence of DOM had a negative impact on the removal of all OMPs after 30 min of adsorption, but similar removals to ultra-pure water were obtained for 6 OMPs after 72 h of adsorption. This demonstrated that competition between DOM and OMPs for adsorption sites was not a major mechanism as compared to pore blockage, which only slowed down the adsorption and did not prevent it. The charge of OMPs had a clear impact: the adsorption of negatively charged compounds was reduced in the presence of wastewater effluent due to repulsive electrostatic interactions with the adsorbed DOM and the PAC surface. On the other hand, the removal of positively charged compounds was improved. A 24 h pre-equilibrium between OMPs and DOM improved their removal onto PAC, which suggest that OMPs and DOM interact in solution which decreased the negative effects caused by the presence of DOM, e.g. through co-adsorption of an OMP-DOM complex.
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23590. 题目: Assessment of C-DBP and N-DBP formation potential and its reduction by MIEX® DOC and MIEX® GOLD resins using fluorescence spectroscopy and parallel factor analysis
文章编号: N20011001
期刊: Water Research
作者: P. Jutaporn, M.D. Armstrong, O. Coronell
更新时间: 2020-01-10
摘要: This study investigated the applicability of parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices (EEM) spectra to assess the formation potentials (FP) of carbonaceous and nitrogenous disinfection byproducts (C-DBP and N-DBP) and the FP reduction by the magnetic ion exchange resins, MIEX® DOC and MIEX® GOLD. Two source waters of different nature — a surface water and a secondary treated wastewater effluent — were studied. The samples were analyzed for formation potentials of trihalomethanes (THM₄), haloacetonitriles (HAN₄), haloketones (HK₂), and chloropicrin (CPN). A 4-component PARAFAC model was developed from 150 EEM samples generated from the raw source waters and their treatment with MIEX® resins. Components C1, C2, and C3 corresponded to humic-like dissolved organic matter (DOM) while C4 corresponded to protein-like DOM. Both MIEX® resins preferentially removed components C1, C2, and C3 over C4, indicating affinity with humic materials. MIEX® resins were shown to be more effective to treat surface water than secondary effluent, including effective removal of DBP precursors with extended bed volume treatment. Among all parameters investigated, THM₄-FP strongly correlated with humic-like component C3, while HAN₄-FP strongly correlated with protein-like component C4 (ρ > 0.89 and p < 0.01); CPN-FP and HK₂-FP both correlated with anthropogenic DOM C2 (ρ > 0.89 and p < 0.01). Our results indicate that EEM–PARAFAC was valuable for assessing DBP formation potentials and removal of their precursors by MIEX® resins in different water sources.
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23591. 题目: Dynamics of inorganic carbon and pH in a large subtropical continental shelf system: Interaction between eutrophication, hypoxia, and ocean acidification
文章编号: N20010913
期刊: Limnology and Oceanography
作者: Yangyang Zhao, Jing Liu, Khanittha Uthaipan, Xue Song, Yi Xu, Biyan He, Hongbin Liu, Jianping Gan, Minhan Dai
更新时间: 2020-01-09
摘要: We examined the dynamics of dissolved inorganic carbon (DIC) and pH in the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS) shelf in summer, aiming for a better understanding of the interaction between eutrophication, hypoxia, and ocean acidification. Using a semi‐analytical diagnostic approach based on validated multiple end‐member water mass mixing models, we showed a −191 ± 54 μmol kg⁻¹ deficit in DIC concentrations in an extensive surface plume bulge, corresponding to a significant pH increase of ∼ 0.57 ± 0.19 units relative to conservative mixing. In contrast, DIC additions in the bottom hypoxic zone reached ∼ 139 ± 21 μmol kg⁻¹, accompanied by a decrease in pH of −0.30 ± 0.04 units. In combination with stable carbon isotopic compositions, we found biological production and CO₂ outgassing to be responsible for DIC deficits in surface waters, while degradation of organic matter (OM) accounted for DIC additions in bottom waters. The PRE‐NSCS plume system as a whole served as a net source of atmospheric CO₂ from the perspective of Lagrangian observations, because strong CO₂ outgassing in the inner estuary overwhelmed the CO₂ uptake in the plume despite strong phytoplankton blooms. Using a two‐layer box model, we further estimated that at least ∼ 45 ± 13% of eutrophication‐driven OM production in the surface plume accounted for 67 ± 18% of the DIC addition and oxygen consumption in bottom waters. Eutrophication also buffered ocean acidification in surface waters while hypoxia enhanced it in bottom waters, but their effects on acid‐base buffering capacity were secondary to the amplification of coastal ocean acidification caused by freshwater inputs.

23592. 题目: Manganese-modified biochar for highly efficient sorption of cadmium
文章编号: N20010912
期刊: Environmental Science and Pollution Research
作者: Xiao Tan, Wenxia Wei, Congbin Xu, Yue Meng, Wenrong Bai, Wenjie Yang, Aijun Lin
更新时间: 2020-01-09
摘要: In this study, corn stalk was modified by manganese (Mn) before (MBC₁) and after (MBC₂) pyrolysis at different temperatures (400~600 °C) under anaerobic conditions for Cd sorption in both water and soil. Batch experiments in aqueous solution were conducted to evaluate the optimum sorption capability by biochar with and without manganese-modified. Both types of manganese modification can improve the sorption capacity of Cd(II) on biochar, which is superior to the corresponding pristine biochar without modification, especially, pyrolyzed at 500 °C with 5:1 modification ratio. Under the optimal preparation conditions, the sorption percentage on MBC₂ was 11.01% higher than that of MBC₁. The maximum sorption capacity of MBC₂ was 191.94 mg g⁻¹ calculated by isotherm model. The performance of MBC₂ was also verified in soil stabilization experiments in Cd-contaminated soil. We can conclude from the results of BCR extraction that all the application rates of MBC₂ (1%, 2%, and 3%) can reduce the mild acid-soluble fraction Cd. The reducible, oxidizable, and residual fraction Cd showed an upward trend, thus controlling the migration, transformation, and enrichment of Cd in soil. The characteristic analysis showed biochar has more irregular fold and more particle-aggregated surface after modification. The main components of these aggregated particles are manganese oxides (MnO_x) with high sorption capacity, such as the MnO_x crystal structure loaded on MBC₂ is a mixed structure of δ-MnO₂ and MnO. However, these particles may block the biochar pores, or some of the pores may collapse at high temperatures during the modification process. The specific surface area was reduced, even if the sorption effect of MBC was strongly enhanced. Meanwhile, under the action of the secondary pyrolysis of MBC₂ modification process, the MBC₂ has a higher degree of aromatization with more potential active sorption sites for Cd. The study concluded that the MBC₂ could be a promising amendment for Cd in both water and soil real field applications.

23593. 题目: Catalytic conversion of gaseous tars using land, coastal and marine biomass-derived char catalysts in a bench-scale downstream combined fixed bed system
文章编号: N20010911
期刊: Bioresource Technology
作者: Jie Li, Zhengyi Liu, Yuanyu Tian, Yanan Zhu, Song Qin, Yingyun Qiao
更新时间: 2020-01-09
摘要: The catalytic activity of biochar for tar removal was evaluated in a bench-scale combined fixed bed reactor by comparison of gaseous tar catalytic cracking behaviors over land (Corn stalks, Cs), coastal (Reed, Re) and marine (Sargassum horneri, Sh) char catalyst. The experiments demonstrated that the tar yield after addition of the biochar was reduced significantly; the tar conversion efficiency reached to 94.6 % for catalytic at 850°C with 50 mm char bed length using Re char. And the yield and composition of gas also changed markedly. The percentage of H₂ and CO in the product gas were obviously increased. Sh has a higher H₂ content (49.3% of the total gas content), whereas, CO dominated in the gas products for Cs (45.4%) and Re (48.1%). The results from GC-MS analysis illustrated that the increase in temperature promoted the tar cracking and also promotes the polymerization of some tar components.
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23594. 题目: Goethite and hematite in bichromic soil profiles of southern Brazil: Xanthization or yellowing process
文章编号: N20010910
期刊: CATENA
作者: Vander Freitas Melo, Jairo Calderari de Oliveira Jr., Araína Hulmann Batista, Verediana Fernanda Cherobim, Nerilde Favaretto
更新时间: 2020-01-09
摘要: Hematite (Hm) and goethite (Gt) in tropical and subtropical soils stand out as indicators of different pedogenic and geochemical environments. The objective of this work was to characterize the geochemical and crystallographic changes of Hm and Gt in profiles of bichromic soils as a tool to interpret the xanthization process (yellowing) in the superficial horizons, which were higher in organic matter. Soil profiles from three sedimentary rocks (claystone, sandstone and varvite) were selected. The clay fractions of the soil horizons and the Fe-concentrated rock samples (varvite and sandstone were ground in a disc mill, sieved with a 325 mesh, and treated with 20% HF) were subjected to modified and less-aggressive citrate-bicarbonate-dithionite (CBD) extractions (Fe-release kinetics) and X-ray diffraction (XRD) analysis. The parent rocks released lithogenic Hm and Gt into the soils and in the superficial horizons, and most of the Hm was dissolved and the Fe recrystallized as Gt. The yellow superficial horizons contained two Gt populations: Gt with fewer isomorphic substitutions of Fe by Al (lithogenic) and Gt with more isomorphic substitutions and with smaller mean crystal diameters (pedogenic). The isomorphic substitutions conferred greater stability to the minerals, so Gt had greater resistance than Hm to the CBD extractions. After successive extractions with CBD, Hm tended toward an isodimensional form. Our data confirmed that the lower stability of Hm and the high electron concentrations due to high organic matter contents resulted on yellowing of the superficial horizons.

23595. 题目: Remediation of cadmium and lead polluted soil using thiol-modified biochar
文章编号: N20010909
期刊: Journal of Hazardous Materials
作者: Jiajun Fan, Chao Cai, Haifeng Chi, Brian J. Reid, Frédéric Coulon, Youchi Zhang, Yanwei Hou
更新时间: 2020-01-09
摘要: Thiol-modified rice straw biochar (RS) was prepared by an esterification reaction with β-mercaptoethanol and used for the remediation of Cd and Pb polluted soils. Modified biochar was characterized through elemental analysis, BET analysis, FE-SEM, FT-IR and XPS. These analytical results revealed that thiol groups were successfully grafted onto the surface of the biochar and were involved in metal ion complexation. Batch sorption experiments indicated that Cd²⁺ and Pb²⁺ sorption onto RS described well by a pseudo second order kinetic model and a Langmuir isotherm. The maximum adsorption capacities for Cd²⁺ and Pb²⁺, in the single-metal systems, were 45.1 and 61.4 mg g^-1, respectively. In the binary-metal systems, RS selectively adsorbed Cd²⁺ over Pb²⁺. Cd²⁺ and Pb²⁺ were removed mainly through surface complexation. In the soil incubation experiments (28 days), RS reduced the available Cd by 34.8-39.2%; while, RS reduced the available Pb by 8.6%-11.1%. This research demonstrates RS as a potentially effective amendment for the remediation of heavy metal polluted soils.
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23596. 题目: Preparation, environmental application and prospect of biochar-supported metal nanoparticles: A review
文章编号: N20010908
期刊: Journal of Hazardous Materials
作者: Jiwei Liu, Jianguo Jiang, Yuan Meng, Aikelaimu Aihemaiti, Yiwen Xu, Honglin Xiang, Yuchen Gao, Xuejing Chen
更新时间: 2020-01-09
摘要: Biochar is a low-cost, porous, and carbon-rich material and it exhibits a great potential as an adsorbent and a supporting matrix due to its high surface activity, high specific surface area, and high ion exchange capacity. Metal nanomaterials are nanometer-sized solid particles which have high reactivity, high surface area, and high surface energy. Owing to their aggregation and passivation, metal nanomaterials will lose excellent physiochemical properties. Carbon-enriched biochar can be applied to overcome these drawbacks of metal nanomaterials. Combining the advantages of biochar and metal nanomaterials, supporting metal nanomaterials on porous and stable biochar creates a new biochar-supported metal nanoparticles (MNPs@BC). Therefore, MNPs@BC can be used to design the properties of metal nanoparticles, stabilize the anchored metal nanoparticles, and facilitate the catalytic/redox reactions at the biochar-metal interfaces, which maximizes the efficiency of biochar and metal nanoparticles in environmental application. This work detailedly reviews the synthesis methods of MNPs@BC and the effects of preparation conditions on the properties of MNPs@BC during the preparation processes. The characterization methods of MNPs@BC, the removal/remediation performance of MNPs@BC for organic contaminants, heavy metals and other inorganic contaminants in water and soil, and the effect of MNPs@BC properties on the remediation efficiency were discussed. In addition, this paper summarizes the effect of various parameters on the removal of contaminants from water, the effect of MNPs@BC remediation on soil properties, and the removal/remediation mechanisms of the contaminants by MNPs@BC in water and soil. Moreover, the potential directions for future research and development of MNPs@BC have also been discussed.
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23597. 题目: Municipal sludge dewatering properties and heavy metal distribution: Effects of surfactant and hydrothermal treatment
文章编号: N20010907
期刊: Science of The Total Environment
作者: Xingshuang Liu, Jin Wang, Enhui Liu, Tianhua Yang, Rundong Li, Yifei Sun
更新时间: 2020-01-09
摘要: Extracellular polymeric substances (EPS) play an important role in reducing moisture content and removing heavy metals from municipal sludge. In this study, cetyl trimethyl ammonium bromide (CTAB) and primary alcohol ethoxylate (AEO₉) were used to prepare complex surfactants. Municipal sludge was treated with mixed surfactants and hydrothermal treatment (HTT) to test the sludge dewatering and heavy metal adsorption performance of EPS treated with varying proportions and contents of surfactants. The results showed that EPS with different proportions had different adsorption capacities for major heavy metals in sludge was 20.48%–29.82%. The adsorption capacity of EPS on heavy metals is significantly positively correlated with protein content (R² = 0.9266, P = .00). There is no significant correlation between polysaccharides (R² = 0.0092, P = .00) and nucleic acids (R² = 0.0638, P = .00) and heavy metal adsorption capacity. Combined treatment of 10% CTAB, 15% AEO₉, and HTT produced the minimal bound water content in treated sludge, zeta potential increased by 49.2 mV and sludge specific resistance is only 0.66% of the raw sludge.
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23598. 题目: Associative effects of lignin-derived biochar and arbuscular mycorrhizal fungi applied to soil polluted from Pb-acid batteries effluents on barley grain safety
文章编号: N20010906
期刊: Science of The Total Environment
作者: Muhammad Asaf Khan, Mahmood-ur-Rahman, Pia Muhammad Adnan Ramzani, Muhammad Zubair, Bilal Rasool, Muhammad Kamran Khan, Ammar Ahmed, Shahbaz Ali Khan, Veysel Turan, Muhammad Iqbal
更新时间: 2020-01-09
摘要: While disobeying environmental regulations of Pakistan, several Pb-acid batteries recycling and repairing units discharge their effluents into water canals that irrigate arable fields. Resultantly, serious ecological risks, as well as human health hazards through consumption of edible crops grown on such Pb-polluted soils have been reported. In this experiment, we observed associative effects of amending a soil polluted from Pb-acid batteries effluents (SPB) with arbuscular mycorrhizal fungi (AMF) and lignin-derived biochar (LBC) on barley grain safety to human health. The SPB was treated with AMF inoculum (a consortium of four AMF species), lignin (LN), and LBC, as sole treatments and AMF inoculum with LN and LBC. Barley parameters involving Pb distribution in grain and other parts, grain biochemistry, and nutrition were assessed. Likewise, Pb bioavailability in SPB, AMF root colonization, soil enzymes, microbial biomass carbon (MBC), and AMF produced total glomalin related soil protein (TGSP) were also scoped. Additionally, human renal cells (HEK 293) cytotoxicity test was performed by opting barley grain-related Pb concentrations. Results show that LBC + AMF significantly reduced grain Pb concentrations below the critical limit [4.67 mg kg⁻¹ (WHO/FAO standard)], AMF colonization, MBC, soil enzymology, and TGSP, compared to control. Likewise, rest barley parameters were also improved in this treatment. Contrary to other treatments, grain produced on LBC + AMF did not result in (a) cell apoptosis, (b) cell distortion and (c) cohesion loss. Immobilization of Pb in SPB was due to the dilution effect of Pb adsorption on LBC, AMF mycelium and TGSP which resulted in a significant drop of grain Pb concentrations below the critical limit and ultimately no harm to HEK 293 cells. Our findings endorse that grain produced at LBC + AMF treatment are safer for human consumption and will not pose health risks. The LBC + AMF application can remediate SPB for safer cereal production.
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23599. 题目: Adsorption behavior of tetracycline onto Spirulina sp. (microalgae)-derived biochars produced at different temperatures
文章编号: N20010905
期刊: Science of The Total Environment
作者: Yong-Keun Choi, Tae-Rim Choi, Ranjit Gurav, Shashi Kant Bhatia, Ye-Lim Park, Hyung Joo Kim, Eunsung Kan, Yung-Hun Yang
更新时间: 2020-01-09
摘要: We evaluated the production of Spirulina sp. (microalgae)-derived biochars (SPAL-BCs) at different pyrolysis temperatures for the removal of an emerging water contaminant, tetracycline (TC). Physicochemical properties of SPAL-BCs were characterized and related with their capacity to adsorb TC. Increasing pyrolysis temperatures led to higher aromaticity, higher hydrophobicity, and higher specific surface area. In particular, SPAL-BC750 possessed the highest hydrophobicity, various strong crystallizations (i.e., calcite, hydroxyapatite, and rhenanite) and functional groups (i.e., CH₂, CN, CO, and CO₃²⁻), which may be associated with high TC adsorption. SPAL-BC750 also presented the highest TC adsorption capacity (132.8 mg TC/g biochar) via batch experimentation because of hydrophobic, π-π interactions, functional groups, and metal complexation. The best fitting isotherm and kinetic models of TC adsorption by SPAL-BC750 were the Langmuir and pseudo-first order models, respectively. SPAL-BCs obtained as a by-product of pyrolysis may be an economical and potentially valuable adsorbent for aqueous antibiotic removal.
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23600. 题目: Spectroscopic and molecular-level characteristics of dissolved organic matter in the Pearl River Estuary, South China
文章编号: N20010904
期刊: Science of The Total Environment
作者: Yuchen Liu, Quanhui Ye, Wan-Ling Huang, Lian Feng, Ying-Hui Wang, Zheng Xie, Shan-Shan Yong, Song Zhang, Bin Jiang, Yan Zheng, Jun-Jian Wang
更新时间: 2020-01-09
摘要: Coastal populations are expanding globally, resulting in great anthropogenic impacts on the organic matter in estuaries and regional carbon cycles. However, the molecular-level characteristics of dissolved organic matter (DOM) within highly disturbed estuaries are still not well understood. Here, water samples collected during two seasons (wet and dry) from the subtropical Pearl River Estuary of China were analyzed using absorption and fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to determine the spatiotemporal variations in the DOM characteristics. In the seaward direction, the abundances of chromophoric and fluorescent DOM decreased by greater percentages than the bulk dissolved organic carbon concentration. The spectroscopy and FT-ICR MS analyses collectively indicated seaward declines in the aromaticity of DOM and terrestrial DOM contributions from natural terrestrial markers and anthropogenic synthetic surfactants. In particular, the S content in DOM was much higher here than in previously reported estuaries, suggesting a strong anthropogenic impact on the estuarine DOM. Greater terrestrial and anthropogenic signatures in DOM were observed in the wet season than in the dry season. Importantly, this study implies that the terrestrial and anthropogenic contributions to DOM were strongly driven by season in the anthropogenically disturbed subtropical estuary.
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