81. 题目: Soil organic carbon saturation in cropland-grassland systems: Storage potential and soil quality
作者: Thomas Guillaume, David Makowski, Zamir Libohova, Luca Bragazza, Fatbardh Sallaku, Sokrat Sinaj
摘要: Reliable estimations of soil organic carbon (SOC) deficits in agroecosystems are crucial in evaluating the atmospheric C sequestration potential of agricultural soils and supporting management decisions. Nonetheless, the co-benefit on soil quality resulting from SOC accrual is rarely considered. Here, we assessed SOC saturation and soil physical quality in permanent grasslands (PG) and croplands (CR) by applying the C-saturation concept and the SOC:clay ratio as an indicator of soil physical quality to a set of long-term monitoring sites in western Switzerland. For this goal, we produced a new relationship between the silt + clay (SC) particles and the C stored in the mineral-associated fraction (MAOMC) and we assessed the assumption that grasslands can be used as C-saturated reference sites. The saturation in PG was not coincidental as it depended on the C accrual history. Hence, PG with the lowest MAOMC have not reached their C-saturation level and present a potential SOC storage under optimal management. The MAOMC saturation in CR was low (62 ± 4%) and corresponded to a deficit of −8.8 ± 1.2 mg C g−1 soil as compared to the current level in PG. The saturation was mainly affected by the proportion of temporary grassland in the crop rotation. The relative distribution of C between MAOM (∼80%) and the fine and coarse particulate organic matter (POM) was not affected by land-use types. The MAOMC saturation in this study (MAOMC = 0.372 × SC + 4.23) was similar to that reported in the litterature, but discrepancies appeared when the silt and clay contents were considered separately. SC was by far the main factor explaining MAOMC amount in PG (semi-partial R2: 0.66). In contrast to other studies, the C content of MAOM in PG (43 mg C g−1 SC) was not related to the SC content, suggesting a fixed maximal value in C-saturated soils. Nonetheless, MAOMC saturation may be underestimated as the least saturated PG might still accumulate MAOMC. Finally, the SOC:clay ratio was correlated with MAOMC saturation level in CR, but not in PG suggesting that targeting SOC accrual in CR optimizes the benefits between soil C storage and soil quality.
82. 题目: A first assessment of particle flux over the South Brazil bight continental slope
期刊: Deep Sea Research Part I: Oceanographic Research Papers
作者: P.M. Tura, C.H. Pilskaln, F.P. Brandini
摘要: The vertical export of particulate organic carbon (POC) is a key component of the oceanic biological pump, which regulates the distribution of elements associated with primary production in the upper euphotic zone. To better understand how oceanic biogeochemical processes will respond in climate change scenarios, it is necessary to comprehend the mechanisms that regulate the magnitude and variations of POC flux among distinct oceanic domains, including the boundaries between continental margins and oceanic basins. This work is a first assessment of particle flux over the South Brazil Bight continental slope, a tropical western boundary system dominated by the Brazil Current. Total mass flux, and specific carbon, nitrogen and biogenic silica fluxes were measured periodically by two sediment traps installed at 450 m deep over the 900 m isobath, and at 750 m deep over the 2000 m isobath, from November 2016 to September 2017. Due to strong contribution of advected particles, high and extremely irregular fluxes were registered at the 900 m isobath site (mean = 1.1 g m-2 d− 1, stand. dev. ± 2.9 g m-2 d-1). The captured material suggests this sediment trap was affected by turbidity flows, which precludes the estimation of the biological pump contribution over this isobath. Over the 2000 m isobath, POC flux (3.7 mg m-2 d-1; ±2.5 mg m-2 d− 1) followed the seasonal pattern of primary production measured by satellite. POC flux was strongly correlated with biogenic silica content (r = 0.79; p < 0.01). This ballast mineral was more efficient than CaCO3 in transferring carbon from the base of the euphotic zone to 750 m. We suggest intra-seasonal variations found in the POC flux over the 2000 m isobath to be related to Brazil Current instabilities. Measurements of δ15N suggest that higher POC flux occurred during subsurface nitrate-based production regimes. A regional exponential export model is proposed, with a mean exponent (b value) of 1.4 (±0.3). Although initial, the results of this work allow us to estimate that 2.2 × 1012 g C is exported annually over the South Brazil Bight continental slope.
83. 题目: Conversion of Brazilian savannah to agricultural land affects quantity and quality of labile soil organic matter
作者: Rafael S. Santos, Martin Wiesmeier, Dener M.S. Oliveira, Jorge L. Locatelli, Matheus S.C. Barreto, José A.M. Demattê, Carlos E.P. Cerri
摘要: Most studies assessing land-use change (LUC) and management impacts on the soil organic carbon (SOC) budget mainly focused on total soil organic matter (SOM), neglecting its functional fractions such as water-extractable organic matter (WEOM). This may limit a better understanding of SOC dynamics along the soil profile as WEOM plays a key role in several soil and microbial processes. Here, we aimed to obtain a quantitative and qualitative assessment of WEOM dynamics to 1 m depth in areas after native vegetation conversion to long-term agriculture in Brazil. For this purpose, cropland areas under no-tillage (NT; ∼ 23 years old) and native vegetation (NV; i.e., Cerrado vegetation) were evaluated across a transect of 1000 km within Brazil’s new agricultural frontier – the so-called MATOPIBA region. We combined spectroscopic analyses (UV–Vis and DRIFT spectroscopies), C and nitrogen (N) determination in different SOM pools (i.e., bulk SOM, WEOM, and microbial biomass), and microbial measurements [e.g., microbial biomass C (MBC) and N (MBN), and β-glucosidase activity] to better understand changes in WEOM dynamics induced by LUC. We observed that although SOC decreased along the soil profile after NV (4.2–20.7 g kg−1) conversion to NT (3.8–14.2 g kg−1), water-extractable organic C levels (3.6–79.3 mg L−1) were similar between land uses. On the other hand, an increase in water-extractable total N was observed after NV (0.4–4.6 mg L−1) conversion to NT (0.5–19.3 mg L−1). Although MBC and MBN levels decreased for most study sites, β-glucosidase activity increased after LUC indicating intensive microbial processing of SOM. As a result, WEOM had lower aromaticity and molecular weight (i.e., low values of SUVA254 and A2/A3) in NT than NV; and a relative decomposition of aliphatic and polysaccharides over aromatic and amine/amide was observed after LUC through DRIFT spectroscopy. Our study indicates that LUC had stronger impacts on WEOM quality than its quantity, with agricultural areas having more biochemical changes in WEOM than NV.
84. 题目: Characteristics of bio-oil and biochar from cotton stalk pyrolysis: Effects of torrefaction temperature and duration in an ammonia environment
期刊: Bioresource Technology
作者: An Zhao, Shanjian Liu, Jingang Yao, Fupeng Huang, Zhisen He, Jia Liu
摘要: In this study, nitrogen-containing chemicals and nitrogen-rich biochar were prepared using ammonia (NH3) torrefaction pretreatment technology. The effects of temperature and duration of torrefaction on the characteristics of torrefaction and pyrolysis products were evaluated. The results indicated that when the torrefaction temperature was increased to 290°C, the nitrogen content increased significantly from 0.98% to 6.85%. XPS analysis showed that the raw biomass mainly contained amide-N and pyrrole-N. As the torrefaction temperature and duration increased, quaternary-N formation was promoted, while amide-N, pyrrole-N, and pyridine-N were consumed. Potential nitrogen doping and transformation pathways during the ammonia torrefaction process were proposed. GC-MS analysis showed that ammonia torrefaction promoted the formation of pyridines, while reducing the content of oxygen-containing species. In addition, torrefaction duration had positive effects on the yield of nitrogen-containing chemicals.
85. 题目: Eukaryotes in soil aggregates across conservation managements: Major roles of protists, fungi and taxa linkages in soil structuring and C stock
期刊: Soil Biology and Biochemistry
作者: Elisa Pellegrino, Gaia Piazza, Thorunn Helgason, Laura Ercoli
摘要: The stabilization of soil organic carbon (SOC) promoted by conservation agriculture (CA) depends on soil aggregation. Aggregation protects SOC and creates heterogeneous microhabitats hosting diverse soil biota which in turn promote aggregation. A long-term experiment, studying the interaction of tillage with nitrogen (N) fertilization on a soybean-wheat rotation, was used to investigate eukaryotic community diversity, composition, and structure within small macroaggregates (sM) and occluded microaggregates (mM). Using high-throughput Illumina sequencing, we found (i) a different eukaryote diversity response to management intensification across soil aggregates and soil depths; (ii) a conserved core community composition of eukaryotes across CA treatments and aggregates at surface and subsurface layers; (iii) a different effect of tillage on eukaryotic community structure in sM and mM along the soil profile according to N availability; (iv) a positive association of protists, and fungi with the amount of sM and mM, and their SOC content; (v) a stronger complexity of within- and cross-domain networks (eukaryotes and eukaryotes-prokaryotes) in mM than in sM at surface layer. Overall, our findings demonstrated for the first time that protists together with fungi play major roles in soil structuring and C cycling, and that Cercozoa represent hubs in soil biota aggregate networks.
86. 题目: Feasibility of source identification by DOM fingerprinting in marine pollution events
期刊: Marine Pollution Bulletin
作者: Ming Jiang, Yanqing Sheng, Chongguo Tian, Changyu Li, Qunqun Liu, Zhaoran Li
摘要: Accurate source identification is the first step of pollution control in environmental emergency management, especially in marine pollution events. Dissolved organic matter (DOM) absorption and fluorescence (excitation-emission matrices, EEMs) analyses were applied to trace contaminant sources for a pollution event that occurred along the coast of Laizhou Bay, Bohai Sea. Parallel factor analysis (PARAFAC) of the EEMs identified four fluorescent components: terrestrial humic-like (C1), tryptophan-like (C2), and a mixture of terrestrial and marine humic-like (C3) and tyrosine-like (C4) components. The relationships among C1 to C4 and quality indices indicated that the DOM originated from terrestrial input and biological activity. The EEMs-PARAFAC results accompanied by the optical characteristics of DOM and fingerprinting demonstrated that the marine pollution event occurred was from enterprise emissions. The numerical simulation confirmed the reliability of EEMs-PARAFAC modeling for DOM fingerprinting of pollution sources in polluted regions. This study provided a feasible method for source recognition in marine pollution events.
87. 题目: Adsorption behaviors and mechanisms of antibiotic norfloxacin on degradable and nondegradable microplastics
期刊: Science of The Total Environment
作者: Meng Sun, Yongkui Yang, Menglu Huang, Shaokang Fu, Yuying Hao, Siyu Hu, Donglin Lai, Lin Zhao
摘要: The misuse of both antibiotics and plastics significantly increases the environmental pollution problems associated with these contaminants. Moreover, microplastics can adsorb other pollutants in the environment. However, the mechanisms of antibiotic adsorption by degradable and nondegradable microplastics are not completely understood. In this study, we investigated the environmental behavior of norfloxacin (NOR) using polybutylene succinate (PBS), which is a degradable microplastic, and compared it with conventional microplastics, polystyrene (PS) and polyethylene (PE). The order of adsorption capacity was PS > PBS ≫ PE. The adsorption behavior fitted well with the pseudo-second-order kinetic and Langmuir isotherm models, indicating monolayer adsorption. The process is thermodynamically endothermic and non-spontaneous and is controlled by chemical and physical mechanisms, including π-π conjugation, hydrogen bonds, ion exchange, and electrostatic interactions. The adsorption capacity of microplastics was higher when the solution pH was around the pKa value of NOR than at other pH values. Ionic strength and dissolved organic matter inhibited the adsorption process. For PS and PBS, the amount of NOR adsorbed onto MPs initially decreased and then increased with the increase of coexisting heavy metal ions. Zn2+ and Pb2+ could promote the adsorption of NOR by PE. This study reveals the interaction mechanisms between microplastics and antibiotics and provides a more comprehensive theoretical basis for an ecological environmental risk assessment of different microplastics.
88. 题目: Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms
期刊: Science of The Total Environment
作者: David R. Piatka, Alexander H. Frank, Inga Köhler, Kathrin Castiglione, Robert van Geldern, Johannes A.C. Barth
摘要: Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over a period of 23 months. This helped to map turnover and sources of aqueous carbon before, during, and after bloom events. During bloom events POC isotope values (δ13CPOC) increased up to −17.4‰, after aqueous CO2 (CO2(aq)) fell below an atmospheric equilibration value of 412 μatm. Additionally, carbon isotope enrichment between CO2(aq) and POC (εCO2-phyto) ranged from 2.0to 21.5‰ with lowest fractionations observed at pH values above 8.9. The increase of δ13CPOC and decrease of εCO2-phyto values at low pCO2 and high pH was most likely caused by the activation of the carbon concentrating mechanism (CCM). This mechanism correlated with prevalent assimilation of 13C-enriched HCO3−. Surprisingly, CO2(aq) still contributed more than 50% to the POC pool down to pCO2 values of around 150 μatm. Only after this threshold the reduced εCO2-phyto suggested incorporation of 13C-enriched HCO3−.
89. 题目: Scale dependence in functional equivalence and difference in the soil microbiome
期刊: Soil Biology and Biochemistry
作者: Alexander Polussa, Javier Gonzalez-Rivero, Nicholas Fields, Fiona V. Jevon, Stephen A. Wood, William R. Wieder, Mark A. Bradford
摘要: Climatic history can shape the functioning of soil microbial communities and thus rates of ecosystem processes such as organic matter decomposition. For example, broad spatial scale differences in climatic history, such as contrasting precipitation regimes, have been shown to generate unique microbial functional responses to contemporary moisture conditions. Yet it is an open question as to whether local differences in soil microclimate similarly influence the functional potential of decomposer communities. Here, we use a multi-scale approach within and among two temperate forest field sites to investigate this question. Soils from fifty-four microsites, that vary in their soil moisture climate-regimes, were used as inocula for a common leaf litter (Quercus rubra L.) in a controlled, laboratory microcosm study. Microcosms were placed under dry, mesic and wet lab-moisture conditions and the rate of carbon (C) mineralization of the litter was measured over 202 days. Our results reveal differences in decomposition rates under controlled conditions that highlight broad-scale functional differences between the soil communities at each site. Specifically, we found that C mineralization differed by as much as two-fold for soil communities when compared between the sites. Our results also show that functional differences of soil communities are observable within one site but not the other. In the site where local-scale functional legacies were apparent, the historical soil moisture microclimate-regimes generated as much as an 89% change in C mineralization rates of the leaf litter under the same contemporary, lab-imposed moisture conditions. A similar pattern was not observable in the other site; instead, laboratory moisture conditions explained almost all variation in C mineralization. Notably, for the site with pronounced local-scale functional legacies, there was much greater within-site variation in field-soil microsite moisture than at the site which did not exhibit functional legacies, suggesting that the extent of local-scale variation in microclimate may act as control on whether local-scale functional legacies are observed. Regardless of whether this mechanism does explain our findings, our observations do confirm those from prior studies where regional-scale moisture-regime differences shape microbial function, and extend this prior work by providing evidence that pronounced local-scale differences in soil moisture microclimate-regimes are associated with microbial functional legacies.
90. 题目: Prediction of organic matter accessibility and complexity in anaerobic digestates
期刊: Waste Management
作者: David Fernández-Domínguez, Dominique Patureau, Sabine Houot, Nicolas Sertillanges, Bastien Zennaro, Julie Jimenez
摘要: Further characterization to properly assess the fate of organic matter quality during anaerobic digestion and organic carbon mineralization in soils is required. Organic matter quality based on its accessibility and complexity was employed to successfully classify 28 substrate/digestate pairs through principal components and hierarchical clustering analysis. The two first components explained 58.02% of the variability and four main groups were separated according to the feedstock type. A decrease in the accessibility (16–66%) and an increase in the complexity (34–98%) of the most accessible fractions was noticed. Besides, an increase of non-biodegradable compounds (17–66%) was globally observed after anaerobic digestion. The observed trends in the conversion of organic matter during anaerobic digestion have allowed to fill the gap in the modeling of the anaerobic digestion process chain. Indeed, partial least squares regressions have accurately predicted the organic matter quality of digestates from their inputs (R2 = 0.831, Q2 = 0.593) although the digester operational conditions (temperature and hydraulic retention time) were non-explicative enough. As a novel approach, the predicted digestate quality was used to feed a partial least squares regression model previously developed to predict organic carbon mineralization in soil. The combined models have predicted experimental organic carbon mineralization in soil (R2 = 0.697) with a model quality similar to the model for organic carbon mineralization in soil (R2 = 0.894). This is the first study that has successfully conceived an additional step in the prediction of organic matter fate from raw substrate before anaerobic digestion to soil carbon mineralization.
91. 题目: Zonal simulations for soil organic carbon mapping in coastal wetlands
期刊: Ecological Indicators
作者: Yuan Chi, Dahai Liu, Zuolun Xie
摘要: Digital soil mapping (DSM) has been developed for decades and aims to accurately simulate the soil factors with low cost. However, it still cost considerably in coastal wetlands because of the high difficulty in field survey. A zonal simulation approach was proposed for decreasing the cost of field survey in the premise of high accuracy for soil organic carbon stock mapping in coastal wetlands, and Chongming Island, an important estuarine wetland in China, was used to demonstrate the study. A subzone with an area proportion lower than 20% was identified based on the typicalness of land surface characteristics and soil influencing factors for the whole study area. Entire and zonal simulations were conducted using abundant predictors sourced from remote sensing, partial least square regression, and 10-fold cross validation. The results revealed that root mean squared errors of entire and zonal simulations were 1.70 g/kg and 1.95 g/kg, respectively, which were in a low level compared with those in previous studies and indicated the high simulation accuracy. The zonal simulation exhibited a slightly lower accuracy than the entire simulation, while considerably decreased the cost by more than 50%. The decrease in the cost showed a much more practical significance than the increase in the accuracy in areas with high difficulty in field survey, and the geographical integrity and continuity of the whole study area, the typicalness of the selected subzone, and the spatial extent were the three key points when promoting the zonal simulation in DSM. The soil organic carbon stock in the study area was generally high in areas with good vegetation condition, low soil salinity, complex landscape configuration, and long distances from the sea. Human activities and the resulting landscape fragmentation have been the dominant factor that drives the spatial pattern of soil organic carbon stock.
92. 题目: The potential of date palm waste biochar for single and simultaneous removal of ammonium and phosphate from aqueous solutions
期刊: Journal of Environmental Chemical Engineering
作者: Yohanna Haile Fseha, Banu Sizirici, Ibrahim Yildiz
摘要: Excessive amounts of NH4+ and PO43- cause eutrophication in water resources and harm the environment. The single and simultaneous removal of NH4+ and PO43- ions from aqueous solutions with different date palm waste biochar samples was investigated in batch and fixed bed column studies. The highest removal and adsorption capacities were 99.55% (49.76mg/g) for NH4+, 51.53% (26.90mg/g) for PO43- in single solution; 99.97% (48.74mg/g) for NH4+, 52.42% (27.41mg/g) for PO43- in mixed solutions at pH 7 with biochar pyrolyzed at 500 °C derived from the mixture of date palm leaves and fronds waste. The experimental data for NH4+ and PO43- fits well to the Langmuir isotherm model (R2=0.87 to 1) and the pseudo-second order kinetic model (R2 = 1) for single and mixed solutions. The increases in biochar bed depth and initial ion concentrations, and the decrease in the initial flow rate increased the exhaustion time, removal efficiencies, and dynamic adsorption capacities of both NH4+ and PO43- in single and mixed solutions. The maximum removal efficiencies and adsorption capacities were 82.22% (805mg/g) for NH4+, 27.51% (92.78mg/g) for PO43- in single solutions; 57.9% (165.17mg/g) for NH4+, 31.56% (85.95mg/g) for PO43- in mixed solutions. Regenerated biochar had still high removal efficiencies and adsorption capacities towards those ions. The NH4+ and/or PO43- ions adsorption on biochar samples were confirmed via Fourier transform infrared spectroscopy, Scanning electron microscopy, Energy dispersive X-ray and X-ray diffraction analysis.
93. 题目: Natural organic matter (NOM) and turbidity removal by plant-based coagulants: a review
期刊: Journal of Environmental Chemical Engineering
作者: B.U. Okoro, S. Sharifi, M.A. Jesson, J. Bridgeman
摘要: NOM deteriorates water quality by forming taste, clarification, colour, and odour problems. It also increases coagulant and chlorine consumption which can initiate disinfection by-products harmful to human health. The coagulation-flocculation (CF) technique is an established method commonly employed to remove NOM in water treatment. Plant-based coagulant products (PCPs) derived from plants like the Moringa oleifera (MO) Strychnos potatorum Linn and Opuntia ficus indica, have been studied and proposed as sustainable alternatives to chemical coagulant, like, aluminium sulphate due to their abundant availability, low cost, low sludge volume and disposal cost, and biodegradability. This review paper provides an overview of the most widely studied plant-based coagulants and discusses their NOM and turbidity removal. It investigates recent analytical tools applied in their characterisation and floc morphological studies. The paper also investigates the effects of operating parameters such as coagulant dose, temperature, and pH, on NOM and turbidity removal. It also reviews up-to-date PCPs biophysical properties and CF mechanism and examines the efficiency of their extraction methods in reducing NOM. Finally, it discusses and suggests ways to overcome commercialisation draw-back caused by nutrient addition.
94. 题目: Hydrothermal synthesis of a novel ecological revetment material by sediment mixed with biochar
期刊: Journal of Cleaner Production
作者: Weihao Zhu, Jian Li, Yafei Zhang, Jiajun Miao, Mingzhao Cheng, Aihua Yao, Zhenzi Jing
摘要: Ecological revetment, as a sustainable way of ecological construction of water conservancy projects, has attracted much attention. Herein, we synthesized a novel revetment material hydrothermally with the local sediment enriched with biochar made from waste biomass. The effect of Ca(OH)2 content, biochar content, curing temperature and curing time on the strength and porous structure of the material was studied, and with 25 mass% Ca(OH)2 and 2 mass% biochar cured at 200 °C for 12 h, the synthesized materials possess a lower pH (≤9.32), higher flexural strength (20.8 MPa) and superior removal performance of nitrogen (45%), phosphorus (100%) and heavy metals (≥90%). The formation of C–S–H and tobermorite in the matrix were found to enhance the strength of the materials, and the porous structure was attributed to the original porous structure of sediments, further the formed tobermorite and added biochar. The Sorption kinetics and equilibria of the material for heavy metals followed pseudo-second order and Langmuir isotherm equations respectively, which indicates that the main mechanism of adsorption for heavy metals mainly is attributed to the chemical adsorption. In addition, the synthesized materials were used as revetments in Beiheng River (Shanghai, China), which provides a site for demonstration of the flood control and ecological restoration.
95. 题目: Natural bioaugmentation enhances the application potential of biochar for Cd remediation
期刊: Separation and Purification Technology
作者: Song Liu, Xuesong Luo, Yonghui Xing, Shuxin Tan, Yi Jiang, Qiaoyun Huang, Wenli Chen
摘要: As the reuse of agricultural and forestry waste, leaf biochar can remove heavy metals from the environment, avoid secondary pollution while creating economic and environmental benefits for society. Our research presents an innovative approach to preparing efficient adsorbents for the first time using natural bioaugmentation (decay) pretreatment of fallen leaves biomass followed by pyrolysis to biochar. Compared with the pristine biochar derived from leaf (BC), the natural bioaugmentation biochar (NBC) characterization showed that the enhancement of microstructure increased the specific surface area, the change of surface composition increased the oxygen-containing functional groups and active adsorption sites, and the increase of porosity improved the mass transfer rate, resulting in a 2-fold increase of Cd(II) fixation capacity. Langmuir and pseudo-second-order models demonstrated that Cd(II) adhered to the NBC core sites through chemical reaction sites by a spontaneous process. The release of nutrients and changes in soil pH after NBC addition to contaminated soil enhanced the stability of the ecosystem and promoted plant growth. This study illustrates for the first time the great potential of natural bioaugmentation (decay) leaf-derived biochar for heavy metal adsorption and provides a new idea to explore the reuse of cellulose waste resources.
96. 题目: Co3O4-MnO2 nanoparticles moored on biochar as a catalyst for activation of peroxymonosulfate to efficiently degrade sulfonamide antibiotics
期刊: Separation and Purification Technology
作者: Zhuorui Jiang, Yuxin Li, Yuxiao Zhou, Xiaoyu Liu, Changhua Wang, Yeqing Lan, Ying Li
摘要: Co3O4-MnO2/BC, as an efficient activator of peroxymonosulfate (PMS) for the decomposition of soluble sulfonamide antibiotics, was successfully obtained via anchoring Co3O4-MnO2 nanoparticles on rice straw biochar (BC). The results demonstrated that 25 mg/L sulfadiazine (SDZ) could be thoroughly destructed by a combination of PMS (1 mM) and Co3O4-MnO2/BC (0.1 g/L) within 10 min. The pseudo-first-order rate constant (k) of the SDZ degradation was high up to 0.482 min-1, which was much larger than those reported in previous literature. The superior stability of the catalyst was confirmed through 5 recycle runs with approximately 100% degradation of SDZ and less than < 0.7 mg/L leached metal ions. Singlet oxygen (1O2) and sulfate radicals (SO4•−) were proved to be the principal reactive oxygen species (ROS) responsible for the degradation of SDZ. Combining the identification of ROS as well as intermediates during the SDZ degradation process, the possible catalytic mechanisms and the pathways of the SDZ degradation were deduced. The results further demonstrated that the combination of Co3O4-MnO2/BC and PMS also possessed a universal degradation capacity towards other typical organic pollutants, such as sulfisoxazole, sulfamethoxazole, bisphenol A and phenacetin. This is the first report on high-efficient heterogeneous activating PMS by Co3O4-MnO2/BC to eliminate soluble sulfonamide antibiotics, which makes it valuable for developing eco-friendly and efficient catalysts for the PMS activation.
97. 题目: In situ fractionation and redox speciation of arsenic in soda lakes of Nhecolândia (Pantanal, Brazil) using the diffusive gradients in thin films (DGT) technique
作者: Lucas Pellegrini Elias, Amauri Antonio Menegário, Amauris Hechevarria Hernandez, Carlos Eduardo Eismann, José Lucas Martins Viana, Jorge Henrique Pedrobom, Edson Geraldo de Oliveira Junior, Laurent Barbiero, Anne Hélène Fostier
摘要: In situ fractionation and redox speciation of As in three different saline-alkaline lakes (green, black and crystalline lakes) in the Pantanal of Nhecolândia (Brazil) were performed by using Diffusive Gradients in Thin films (DGT). The results indicated that As is present mainly in dissolved form. Total As concentration was similar when using different filter membranes, demonstrating that the species adsorbed by DGT devices were <10 kDa. Higher concentrations of labile total As were observed in the center of the lakes, indicating that the nature of the organic matter influences the formation of As complexes. Total As concentrations determined by using ZrO2 DGT were consistent with As concentration in ultrafiltered water samples collected in the black lake. However, part of the data about As(III) obtained in grab samples contrasted with DGT results. The differences observed may indicate that alterations in the species occur during the storage period before analysis by ultrafiltration. As(III) concentrations measured by DGT in the black and crystalline lakes were 1-3 μg L-1 and 4-7 μg L-1, respectively, accounting for only 4%–8% of the total DGT inorganic As. In the green lake, As(III) concentrations were significantly higher at the center (217 μg L−1). Both the phytoplankton community and the dissolved organic carbon influence the As speciation and bioavailability in the lakes of Nhecolândia. The DGT approach used in the present work was able to perform As speciation and demonstrates that in situ sampling analytical techniques are essential in understanding As speciation and its behavior in complex natural aquatic systems.
98. 题目: Interaction between humic acid and silica in reverse osmosis membrane fouling process: A spectroscopic and molecular dynamics insight
期刊: Water Research
作者: Danyang Li, Weichen Lin, Ruipeng Shao, Yue-Xiao Shen, Xianzheng Zhu, Xia Huang
摘要: Combined organic and inorganic fouling is a primary barrier constraining the performance of reverse osmosis (RO) membrane. In this work, we conducted a systematic study focusing on the synergetic fouling effects of silica and humic acid (HA) in RO process, and found the critical silica concentration where the fouling pattern changed qualitatively. When the silica concentration was lower than 6 mM at a typical HA concentration of 50 mg•L−1, no severe fouling was observed, while silica reaching this critical point could cause severe synergetic fouling with HA. Concentrated silica above the critical point acted as the prior foulant with marginal fouling effect caused by HA. A variety of solutions and surface-based characterizations were performed to elucidate the synergistic fouling responsibility for silica and HA. Our study suggests that the carboxylic groups from HA formed hydrogen bonds with silica hydrate, inducing silica adsorption onto HA aggregates at low silica particle concentrations. The HA network was bridged together to form large foulants due to the silica-silica interaction above the silica critical concentration. These mechanisms were further confirmed by molecular dynamics simulations. This study provides an in-depth insight into the combined organic-inorganic fouling and can serve as a guideline to optimize feed conditions in order to mitigate fouling of RO in wastewater reusing industry.
99. 题目: Biogeochemical and mineralogical effects of Fe-P-S dynamics in sediments of continental shelf sea: Impact of salinity, oxygen conditions, and catchment area characteristics
期刊: Science of The Total Environment
作者: Katarzyna Łukawska-Matuszewska, Olga Brocławik, Aleksandra Brodecka-Goluch, Grzegorz Rzepa, Maciej Manecki, Jerzy Bolałek
摘要: In this study, we investigate how salinity, oxygen concentration and catchment area characteristics impact the dynamics of Fe-P-S cycling in the continental shelf sea sediments. Samples were collected from three sites representing different environmental conditions: Gdańsk Deep (southern Baltic Sea), Gotland Deep (central Baltic Sea) and Bothnian Sea (northern Baltic Sea). Sediments were analysed for their mineral composition and speciation of iron and phosphorus. The main groups of Prokaryota involved in Fe-P-S cycling in sediments were indicated. Concentrations of sulphate, hydrogen sulphide, alkalinity, chloride, calcium, phosphate and iron were measured in pore waters. We demonstrated that in the eutrophicated southern region with moderate salinity and oxygen deficit in bottom water, sediments had high potential for retaining Fe and releasing P as indicated by high concentrations of pyrite and labile forms of phosphorus, respectively. Strong salinity and redox stratification in the central Baltic Sea resulted in a clearly higher rate of pyrite deposition. Sediment was enriched with Mn due to the formation of Ca-Mn carbonates driven by intensive Mn redox cycling and sulphate reduction. Because of high availability of Mn oxides connected with episodic inflows of oxic seawater from the North Sea, sulphate was present in the entire profile of the studied sediments in the Gotland Deep. Sediments in the well-oxygenated, virtually fresh and rich in land-derived iron northern Baltic Sea retained significant amounts of P in authigenic minerals. Organic matter mineralisation in the surface sediment of this area was dominated by iron reduction. The variability of environmental conditions and consequent availability of electron acceptors were the cause of regional differences in the composition of Prokaryota communities – the number of sulphate reducers in the Gdańsk and Gotland Deeps was greater than in the Bothnian Sea, where there were more Fe reducers and bacteria that oxidise Fe and S.
100. 题目: Distributions and interactions of dissolved organic matter and heavy metals in shallow groundwater in Guanzhong basin of China
期刊: Environmental Research
作者: Lu Dong, Jian Zhang, Zizhang Guo, Ming Li, Haiming Wu
摘要: Groundwater as the primary source of fresh water particularly in semi-arid regions is heavily threatened by various pollutants such as dissolved organic matter (DOM) and heavy metals due to anthropogenic activities. In this study, 113 shallow groundwater samples were collected from Guanzhong basin of China to explore spatial distributions and interactions of DOM and heavy metals (Fe, Mn and Cu). Fluorescence excitation-emission spectrophotometry with parallel factor analysis showed that DOM in groundwater mainly contained three humic-like and two protein-like substances with an average dissolved organic carbon (DOC) concentration of 12.85 mg L−1. Average Mn and Cu concentrations in groundwater were 19.92 μg L−1 and 7.05 μg L−1 with an increasing trend from west to east, whereas Fe concentration in central regions was much higher (34.23 μg L−1). Structural equation modeling analysis indicated that DOM in groundwater could be significantly affected by surface water, and heavy metals were influenced by urbanization. Moreover, DOM could strongly influence the bioavailability, migration, and transformation of Mn in groundwater. These findings would be beneficial for the effective utilization and protection of groundwater resources.