论文检索

总访问量：4705467次

总访客量：218225人

所有论文

23301. 题目: Microplastic identification and quantification from organic rich sediments: A validated laboratory protocol
文章编号: N20031103
期刊: Environmental Pollution
作者: P. Vermeiren, C. Muñoz, K. Ikejima
更新时间: 2020-03-11
摘要: Plastic pollution presents a global environmental concern with potentially widespread ecological, socio-economic and health implications. Methodological advances in microplastic extraction, quantification and identification from sediments have been made. However, integrating these fragmentary advances into a holistic, cost-effective protocol and applying it to organic rich sediments with fine grain size remains a challenge. Nonetheless, many hot spots of microplastic contamination such as harbour and estuarine sediments are characterised by such sediments. We conducted a series of experiments to integrate methodological advances, and clarify their applicability to organic rich sediments with fine grain size. The resulting protocol consisted of three stages. First, pre-treatment with Fenton's reagent was found to be efficient in reducing organic matter content, compatible with later Fourier Transform-Infrared Spectroscopy (FT-IR) for polymer identification, although it did affect the size of polyethylene (PE) and polyethylene terephthalate (PET). Secondly, a novel density separation column with a top overflow (the OC-T) obtained recovery rates above 90% for microplastics present in a ZnCL2 solution. Finally, automated epifluorescence microscopic image analysis of Nile Red stained filters with selected validation of polymer identities using FT-IR revealed 91.7% of stained particles to be plastics. A case study on estuarine sediments demonstrated a high extraction efficiency with quantification possible down to 125 μm and detection possible down to 62.5 μm. This makes this protocol suitable for large scale monitoring of microplastics in sediments of estuarine origin provided polymer specific recovery rates, background contamination and uncertainty in Nile Red identification is accounted for. Subject to further validation, the protocol could also offer a solution to similar organic rich sediments with fine grain size, such as some soils and sludge, to improve our ability to conduct cost-effective, large scale monitoring of microplastic contamination.

23302. 题目: Assessing the effectiveness of riparian buffers for reducing organic nitrogen loads in the Coastal Plain of the Chesapeake Bay watershed using a watershed model
文章编号: N20031102
期刊: Journal of Hydrology
作者: Sangchul Lee, Gregory W. McCarty, Glenn E. Moglen, Xia Li, Carlington W. Wallace
更新时间: 2020-03-11
摘要: Riparian buffers are an important conservation practice to mitigate water quality degradation in the Coastal Plain of the Chesapeake Bay watershed (CBW). Although forested and grassed riparian buffers have been implemented in this region through government programs, the impacts of riparian buffers on water quality have been rarely examined. The objective of this study was to assess the long-term effects of riparian buffers to improve water quality in the Coastal Plain of the CBW. A watershed model, Soil and Water Assessment Tool (SWAT), was employed for this study. Considering impacts of model uncertainty (i.e., equifinality) on the effectiveness of riparian buffers, we adopted all parameter sets that produced acceptable simulation results. Multiple riparian buffer implementation scenarios were developed to generate the baseline condition on total organic nitrogen (TON) loads without riparian buffers and examine variation of TON loads with areal coverage of riparian buffers. Through the calibration processes, a total of 235 acceptable parameter sets were identified and used to simulate TON loads. The simulation results indicated that riparian buffers significantly reduce TON loads. Without riparian buffers, annual TON loads from the 220 km2 study watershed were 18 to 34 metric tons, but declined to 8 to 21 metric tons with riparian buffers. The effectiveness of riparian buffers on reducing annual TON loads increased from 17% to 45% with an increase in the extent of riparian buffer implementation. The effectiveness of riparian buffers tended to be higher during early spring than other seasons as high soil water conditions promote occurrence of surface water flow and thus TON loads. Riparian buffers were more efficient on croplands than other land use types due to high soil nutrient levels caused by fertilizer applications. The effectiveness of riparian buffers differed considerably by parameter set. Thus, efforts to consider model uncertainty are important to provide better insight into the impacts of conservation practices. This study supports ongoing riparian buffer programs for the Mid-Atlantic Coastal Plain by demonstrating the effectiveness of riparian buffers and informing implementation guidelines.

23303. 题目: The ratio of H/C is a useful parameter to predict adsorption of the herbicide metolachlor to biochars
文章编号: N20031101
期刊: Environmental Research
作者: Lan Wei, Yufen Huang, Lianxi Huang, Yanliang Li, Qing Huang, Guizhi Xu, Karin Müller, Hailong Wang, Yong Sik Ok, Zhongzhen Liu
更新时间: 2020-03-11
摘要: Biochar adsorbent was produced by pyrolyzing traditional Chinese medicinal herb residue at 300, 500 and 750 °C (referred to as biochar-300, biochar-500 and biochar-750). Basic physical and chemical analyses, Fourier transform infrared spectroscopy (FT-IR), and thermodynamic analyses were performed to elucidate adsorption and properties of biochar. Biochar adsorption capacity of herbicide metolochlor, as measured by batch-type adsorption experiments by Freundlich constant Kf (mg1−n Ln kg−1), followed the order: biochar-750 > biochar-300 > biochar-500. Thermodynamic analysis suggested that adsorption of metolachlor on biochar was a spontaneous process. The adsorption isotherm for the biochar produced at the highest pyrolysis temperature was characteristic for adsorption process driven by a high surface area of biochar (85.30 m2 g−1), while the adsorption process for the biochar produced at the lowest temperature was controlled by its higher content of organic matter (39.06%) and abundant functional groups. The FT-IR spectra also showed that the biochar prepared at the lowest temperature had the highest number of surface groups. In general, pore-filling induced by the large surface area of the biochar was the dominant adsorption mechanism. When the H/C value was >0.5, the adsorption mechanism of biochar was dominated by surface chemical bond, while pore-filling played a major role when the H/C value was <0.5.

23304. 题目: Sedimentary environment and organic matter accumulation of Neoproterozoic black shale in the North China Craton: A case study of the Tonian Baishugou Formation in the Luonan area
文章编号: N20031007
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Suyun Hu, Kun Wang, Tongshan Wang, Tao Yang, Ping Luo, Shuyuan Shi, Shaoyong Wang, Jian Su
更新时间: 2020-03-10
摘要: With acceleration of oil exploration near the source in the petroleum industry, black shales (BS) play an increasingly important role in oil and gas exploration. Meso-Neoproterozoic BS are well developed in the North China Craton (NCC), China, many of which are identified as potential hydrocarbon source rocks. Although BS from the Mesoproterozoic Era has been widely investigated, few studies were focused on the Neoproterozoic BS so far. Based on petrology and geochemistry analysis, the sedimentary environment, provenance and organic matter accumulation of two BS layers in the Tonian Baishugou Formation from Sujiacun section, Luonan Area, southern NCC were investigated. It suggests that the lower BS (LB) was deposited in a shallow and non-stratified cratonic-interior sea environment with unstable dysoxic or suboxic conditions. The seawater salinity increased from brackish to marine facies conditions due to the decrease of runoff caused by climate cooling. The Upper BS (UB) was deposited in an open paleomarine environment with stable suboxic conditions and brackish salinity in continuously humid and hot paleoclimate. Both BS were derived from granitoids formed by the ca.2.5 Ga collisional-thermal events in the NCC. The OM accumulation rate of UB is higher than that of UB while LB records lower OM loss rate. On these bases, two developmental modes for the BS from the Baishugou Formation were established.

23305. 题目: A magnetic macro-porous biochar sphere as vehicle for the activation and removal of heavy metals from contaminated agricultural soil
文章编号: N20031006
期刊: Chemical Engineering Journal
作者: Yonglin Liu, Jianfei Huang, Huijuan Xu, Yulong Zhang, Tian Hu, Wenzhao Chen, Hanjian Hu, Jinhua Wu, Yongtao Li, Gangbiao Jiang
更新时间: 2020-03-10
摘要: Remediation of contaminated agricultural soils focused on fixing heavy metals in soils to reduce their bioavailability. However, with the influence of pH, redox potential, and microorganism in the soils, heavy metals were likely to be released from a fixed state. The study aims to investigate magnetic porous biochar spheres and their roles in in situ sorption and removal of heavy metal from the contaminated agricultural soil. The magnetic biochar spheres were prepared using alginate and FeCl3 through a one-step gelation to obtain alginate-Fe3+ gel and subsequently pyrolyzed. Results of Ultraviolet–visible spectrophotometer, X-ray diffraction and Fourier transform infrared spectrometer showed the decomposition of alginate and the formation of Fe3O4 and FeCl2 hydrates nanoparticles on the spheres when the spheres were pyrolyzed at 300 °C. Scanning electron microscope image showed that the CFe300 sphere has a macro-porous structure. The CFe300 sphere exhibited good adsorption capacity of hexavalent chromium from aqueous solution. The CFe300 sphere decreased the bioavailable and total cadmium (II) concentrations from 1.55 ± 0.08 to 0.32 ± 0.04 mg/kg and from 2.81 ± 0.02 to 1.39 ± 0.06 mg/kg, respectively. Moreover, the CFe300 sphere decreased bioavailable and total arsenate (V) concentrations from 1.26 ± 0.003 to 0.85 ± 0.01 mg/kg and from 60.23 ± 0.39 to 27.34 ± 0.94 mg/kg, respectively. Subsequently, addition of water into the soil induced the spheres to leave the soil and float on the surface of soil/water mixture. Thus, the magnetic biochar spheres can be much easier to separate from the soil using magnets.

23306. 题目: Changes in soil organic carbon and total nitrogen as affected by primary forest conversion
文章编号: N20031005
期刊: Forest Ecology and Management
作者: Fei Gao, Xiaoyang Cui, Ying Sang, Jinfeng Song
更新时间: 2020-03-10
摘要: Numerous studies have addressed the effects of forest conversion on soil organic carbon (SOC) and total nitrogen (TN); however, knowledge of SOC and TN stocks and SOC stability after primary forest conversion to secondary forest is still lacking. Such an understanding is critical for the accurate estimation of the potential of forest soils to act as carbon sinks. To learn more about the changes in SOC and TN stocks and SOC stability after primary forest conversion, we used a strict paired-plots method and measured bulk-soil and aggregate-associated OC and TN as well as four SOC stability indices, i.e., heterotrophic respiration, alkyl/O-alkyl C ratio, aggregate-occluded OC, and mineral-associated OC, in paired primary and secondary forest plots in Liangshui National Nature Reserve, Heilongjiang Province, Northeast China. The SOC and TN stocks at the 0–15 cm depth significantly increased with the conversion of primary to secondary forest, by 17.11 Mg ha−1 and 2.91 Mg ha−1, respectively, which was mainly due to increases in soil aggregate (>0.053 mm)-associated OC and TN concentrations. The primary forests dominated by conifer tree species had more low-quality plant OC in the organic layer (i.e., higher amounts of litter and forest floor and higher litter C/N ratio), while the secondary forests composed of broadleaf tree species with higher litter and fine root TN and lower C/N ratios accumulated more stable OC (as indicated by the reduced respiration per g of SOC and the greater proportion of aggregate-occluded OC) and TN in the mineral soil. We did not observe significant differences in the alkyl/O-alkyl C ratio or the proportion of mineral-associated OC (<50 µm) between the two forest types, reflecting the insensitivity of some stability indicators to decadal-scale shifts in primary forest conversion. Tree species-specific differences in litter and fine root traits (i.e., C and N) might be the main driving factors affecting the accumulation and stability of SOC and TN. Thus, it is important to identify and select tree species that are beneficial for the sequestration of OC in mineral soil for forest management or afforestation from the perspective of ecosystem carbon sequestration.

23307. 题目: Spirulina hydrothermal carbonization: effect on hydrochar properties and sulfur transformation
文章编号: N20031004
期刊: Bioresource Technology
作者: Zhiming Zhang, Yong Zhao, Tengfei Wang
更新时间: 2020-03-10
摘要: The effect of hydrothermal carbonization (Htc) on the hydrochar properties and sulfur conversion for microalgae was investigated. The sulfur species and distribution in solid and aqueous products produced from different temperature (180-300°C) were evaluated. Results suggested that varying temperature significantly influenced the elemental composition, functional groups of hydrochar, and the sulfur species in the products. With temperature increased, the hydrochar had increased aromatic structure with low H/C and O/C ratio, and more conversion of organic sulfur into liquid as SO42--S, which acquired the highest concentration (293.31 mg/L) at 300°C. The thiophene-S, aromatic-S, and thiazole-S accounted for the main sulfur species in bio-oil, while components of thiophene-S and thiazole-S were decreased at high temperature. In addition, elevated temperature resulted in more sulfur forms (i.e. thiophene) in hydrochar and formation of more inorganic-S species like sulfate.

23308. 题目: Modeling oxygen and organic matter concentration in the intensive rainbow trout (Oncorhynchus mykiss) rearing system
文章编号: N20031003
期刊: Environmental Monitoring and Assessment
作者: Firouzeh Hosseini Galezan, Mohammad Reza Bayati, Omid Safari, Abbas Rohani
更新时间: 2020-03-10
摘要: Dissolved oxygen (DO) as one of the most fundamental parameters of water quality plays a vital role in aquatic life. This study was conducted to predict DO, biological oxygen demand (BOD), and chemical oxygen demand (COD) in an intensive rainbow trout rearing system with different biomass (B). The multilayer perceptron (MLP) and the radial basis function (RBF) neural networks were employed for evaluating the impacts of food parameters (crude protein (CP), consumed feed (CF)), fish parameters (different values of B, and weight gain (WG)), and water quality parameters including temperature (T) and flow rate (Q) on variation of DO, BOD, and COD concentrations. This study's results showed that although both MLP and RBF neural networks are capable to estimate DO, BOD, and COD concentrations, RBF neural network showed better performance compared to MLP neural network. The results of sensitivity analysis indicated that the parameter CF has the highest effect on DO concentration estimation. Independent variables CF, CP, WG, and B showed the highest to the lowest rank of impacts on BOD estimation, respectively. The results also illustrated a decreasing trend of the effects on the estimation error of COD changes simulation by all independent variables, including B, T, WG, CF, CP, and Q, respectively. RBF neural network based on better stability and generalization ability with average root mean square error (RMSE) and mean absolute percentage error (MAPE) values of less than 0.12 and 3% was superior to MLP in DO, BOD, and COD concentration prediction. Moreover, CF was identified as the most effective factor in estima12tion process. Based on the present study results, there are direct relationships between DO, BOD, and COD concentrations and water quality parameters, fish parameters, and food parameters. Food parameters relative to fish and water quality parameters imposed the greatest effects. Improvement in feeding process such as application of intelligence feeding methods and change in fish diet and feeding time can considerably reduce losses in production system.

23309. 题目: Influence of the application of Fe–Mn–La ternary oxide-biochar composites on the properties of arsenic-polluted paddy soil
文章编号: N20031002
期刊: Environmental Science: Processes & Impacts
作者: Lina Lin, Minling Gao, Xuewei Liu, Zhengguo Song
更新时间: 2020-03-10
摘要: Arsenic exists ubiquitously in the soil and has been proved to be of significant hazard to human health upon transmission through food chain. Herein, we determined the effects of Fe–Mn–La ternary oxide-biochar composites (FMLBCs) on arsenic (As) fractionation, soil enzyme activities, and microbial communities in arsenic-polluted soils. The results demonstrated that the proportion of non-swappable As fractions reduced and that of the exchangeable As fractions increased with the addition of FMLBCs. Furthermore, the addition of FMLBCs significantly increased the catalase (CAT) activity (P < 0.05), and an increase of 69.2–268% was observed when 2 wt% FMLBCs were added. Supplementation with biochar or FMLBCs increased the relative abundance of Proteobacteria and Acidobacteria and decreased the relative abundance of Firmicutes; moreover, the effect was more obvious as the addition amount of biochar or FMLBCs increased. In addition, the FMLBCs, except for FMLBC3, increased the content of available phosphorus. Moreover, amendments of FMLBCs led to an increase in the available potassium content by an average of 212%, 113%, and 62.1% in highly polluted soil. Therefore, the FMLBCs affected the physical and chemical properties of soil in different manners. The results suggested that the addition of FMLBCs changed the distribution and increased the immobilization of As in the soil; this could indirectly reduce the risk of the transport of As to rice. The amendment mechanism of FMLBCs may include changes to the physicochemical soil properties and consequently, the soil enzyme activities are affected, which can influence the microbial communities in soils.

23310. 题目: Chemical Alterations of Dissolved Organic Matter by Permanganate Oxidation
文章编号: N20031001
期刊: Environmental Science & Technology
作者: Juliana R Laszakovits, Arpad Somogyi, Allison A MacKay
更新时间: 2020-03-10
摘要: Dissolved organic matter (DOM) is ubiquitous in raw drinking water and can efficiently scavenge oxidants, such as permanganate. Here, changes to DOM induced by permanganate oxidation under typical drinking water treatment conditions (6 μM, 1 h) to bulk DOM properties, DOM functional groups, and DOM chemical formulae were examined for two DOM isolate types (terrestrial and microbial). Permanganate oxidation did not mineralize DOM, rather changes were compositional in nature. Optical properties suggest that permanganate oxidation decreased DOM aromaticity (decreased SUVA-254), decreased DOM electron-donating capacity, and decreased DOM average molecular weight (increased E2/E3 ratios). Fourier-transform-infrared spectroscopy second derivative analyses revealed that permanganate does not oxidize DOM alkene groups, suggesting permanganate access to functional groups may be important. Four ionization techniques were used with ultrahigh-resolution mass spectrometry: negative and positive ion mode electrospray ionization and negative and positive ion mode laser/desorption ionization. The results from all four techniques were combined to understand changes in DOM chemical formulae. It was concluded that nitrogen-containing aromatic compounds and alkylbenzenes were oxidized by permanganate to form nitrogen-containing aliphatic compounds and benzoic acid-containing compounds. This work highlights how multiple ionization techniques coupled with UHR-MS can enable a more detailed characterization of DOM.

23311. 题目: Response of Bacillus vallismortis sp. EPS to exogenous sulfur stress/ induction and its adsorption performance on Cu(II)
文章编号: N20030911
期刊: Chemosphere
作者: Qiuhua Li, Weifeng Song, Mengge Sun, Jiayao Li, Zefeng Yu
更新时间: 2020-03-09
摘要: The chemical composition of EPS (Extracellular Polymeric Substances) produced by Bacillus vallismortis sp. and its adsorption performance on typical heavy metal were studied under Na2S stress/induction at different concentrations. Its structure was characterized by three-dimensional fluorescence spectrogram (3D-EEM), infrared spectrum (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that, when the Na2S stress/induction intensity was 20 mg/L, the protein concentration was nearly doubled compared with Control-EPS (EPS produced by Bacillus vallismortis sp. without exogenous sulfur stress); furthermore, the 3D-EEM results also demonstrated that there was an increase in the protein content, with the –SH content reaching 154.36 μmol/L, which was 48.2% higher than before stress (104.15 μmol/L). Under this condition, S-EPS (EPS produced by Bacillus vallismortis sp. stressed by exogenous sulfur) exhibited the best adsorption effect on Cu(II), with the theoretical maximum adsorption capacity reaching 1428.57 mg/g EPS. FTIR and XPS analyses revealed that the –SH, CO, N–H played a major role in the adsorption of Cu(II); among those, –SH played a key role. Moreover, the adsorption capacity of Cu(II) by S-EPS was correlated with the content of sulfhydryl protein; indeed, the exogenous sulfur stress/induction can effectively regulate the chemical composition of EPS and improve its adsorption performance, which can be crucial in the prevention and control of heavy metal pollution.

23312. 题目: Indices of the dual roles of OM as electron donor and complexing compound involved in As and Fe mobilization in aquifer systems of the Datong Basin
文章编号: N20030910
期刊: Environmental Pollution
作者: Wenjing Liu, Yanxin Wang, Junxia Li, Kun Qian, Xianjun Xie
更新时间: 2020-03-09
摘要: Organic matter (OM) acts as a source of carbon and is strongly implicated in biogeochemical processes, such as metal complexation and redox reactions. To illustrate the effects of OM on As mobilization in aquifers, this study characterized fluorescence features and hydrochemical properties of OM in sediments and groundwater from an As-affected field site located in the Datong Basin. Fluorescence analysis showed sediment and groundwater OM are dominated by oxidized and reduced quinone-like compounds; shorter emission wavelengths observed in groundwater indicated more labile and protein-like organic substances than in sediments. Dissolved As concentrations were positively correlated with dissolved Fe and HCO3− concentrations in middle and deep groundwater, suggesting labile OM degradation promotes the release of As and Fe from sediments into the groundwater. This result also demonstrated more bioavailable OM occurs in groundwater and that labile OM degradation promotes As release. Grain size distribution results indicated sedimentary As, Fe and OM are associated with fine-grained fractions. Sedimentary As content was significantly and positively correlated with Fe2O3 and OM content, suggesting the potential existence of As–Fe-OM ternary complexation; this was further supported by the results of Fourier-transform infrared (FTIR) spectra and extraction experiments. In addition, the ratio of dissolved reduced quinone-like compounds to oxidized quinone-like compounds was positively correlated with both dissolved As and HCO3− concentrations, implying quinone-like compounds participate in the complexation and influence As mobilization. In the reducing environment, labile OM served as the electron donor to maintain microbial respiration and mediated reductive dissolution of Fe minerals. As–Fe-OM ternary complexation in sediments and microbial reduction have a potentially strong impact on As enrichment in groundwater, and therefore are important considerations for regulating As contamination.

23313. 题目: Light absorption and emissions inventory of humic-like substances from simulated rainforest biomass burning in Southeast Asia
文章编号: N20030909
期刊: Environmental Pollution
作者: Jiao Tang, Jun Li, Yangzhi Mo, Mahdi Safaei Khorram, Yingjun Chen, Jianhui Tang, Yanlin Zhang, Jianzhong Song, Gan Zhang
更新时间: 2020-03-09
摘要: Humic-like substances (HULIS) are complex mixtures that are highly associated with brown carbon (BrC) and are important components of biomass burning (BB) emissions. In this study, we investigated the light absorption, emission factors (EFs), and amounts of HULIS emitted from the simulated burning of 27 types of regionally important rainforest biomass in Southeast Asia. We observed that HULIS had a high mass absorption efficiency at 365 nm (MAE365), with an average value of 2.6 ± 0.83 m2 g−1 C. HULIS emitted from BB accounted for 65% ± 13% of the amount of water-soluble organic carbon (WSOC) and 85% ± 10% of the light absorption of WSOC at 365 nm. The EFs of HULIS from BB averaged 2.3 ± 2.1 g kg−1 fuel, and the burning of the four vegetation subtypes (herbaceous plants, shrubs, evergreen trees, and deciduous trees) exhibited different characteristics. The differences in EFs among the subtypes were likely due to differences in lignin content in the vegetation, the burning conditions, or other factors. The light absorption characteristics of HULIS were strongly associated with the EFs. The annual emissions (minimum–maximum) of HULIS from BB in this region in 2016 were 200–371 Gg. Furthermore, the emissions from January to April accounted for 99% of the total annual emissions of HULIS, which is likely the result of the burning activities during this season. The most significant emission regions were Cambodia, Burma, Thailand, and Laos. This study, which evaluated emissions of HULIS by simulating open BB, contributes to a better understanding of the light-absorbing properties and regional budgets of BrC in this region.

23314. 题目: Humic acid coated magnetic particles as highly efficient heterogeneous photo-Fenton materials for wastewater treatments
文章编号: N20030908
期刊: Chemical Engineering Journal
作者: Nuno P.F. Gonçalves, Marco Minella, Debora Fabbri, Paola Calza, Cosimino Malitesta, Elisabetta Mazzotta, Alessandra Bianco Prevot
更新时间: 2020-03-09
摘要: Heterogeneous photo-Fenton reaction with iron-based magnetic materials has been proposed as an alternative to the homogeneous Fenton process to remove contaminants of emerging concern (CECs) because of the low cost, facile recovery and reuse. The iron-based material is not only a reservoir to maintain an effective concentration of iron in solution, but it also activates H2O2 at the surface. Magnetic particles (MPs) coated with different amount of humic acid (HA), prepared by co-precipitation method under anoxic and oxygenated conditions were synthesized. Their features were characterized by different techniques (XPS, XRD, TGA, SEM and FTIR). The ability of those materials to promote Fenton and photo-Fenton-like processes was investigated using 4-chlorophenol as standard substrate. The HA coating increased the catalyst efficiency, both in the dark and under irradiation, showing the best performance at pH below 4 under simulated sunlight. The iron speciation at the MPs surface had a paramount role in the H2O2 (photo)activation, although the processes promoted by the released iron in solution were not negligible on the overall degradation process. It was demonstrated a role of the surface defectivity to promote faster degradations as a consequence of not only a faster photodissolution, but also a higher heterogeneous reactivity promoted by defective sites. The best performing MPs/HA showed high efficiency for the abatement of CECs, namely Carbamazepine, Ibuprofen, Bisphenol A and 5-Tolylbenzotriazole also in real wastewater. The obtained results demonstrated the potential application of the heterogeneous (photo)-Fenton process activated by these inexpensive and environmental friendly materials in advanced wastewater treatments.

23315. 题目: Application of Pb(II) to probe the physiological responses of fungal intracellular vesicles
文章编号: N20030907
期刊: Ecotoxicology and Environmental Safety
作者: Zhongquan Jiang, Tong Wang, Yalin Sun, Ying Nong, Lingyi Tang, Tingting Gu, Shimei Wang, Zhen Li
更新时间: 2020-03-09
摘要: Vesicles (Ves) within fungal cells are the critical linkage between intracellular and extracellular systems. This study explored the application of Pb2+ to probe the physiology of intracellular Ves in Rhodotorula mucilaginosa (Rho). At low Pb2+ levels (0–500 mg/L), there was no evident change in the content of extracellular polymeric substances (EPS) or microbial activity. At medium-high levels (1000–2000 mg/L), the sizes of Ves within the Rho cells were significantly enlarged, with abundant lead nano-particles (Pb NPs) formed either on the cell surface or interior, whereas the EPS content and bioactivity were still stable. At a high level (2500 mg/L), the Rho cells were severely deformed, with cell counts reduced by more than 99%. However, the EPS contents and the respiration rate of the surviving cells dramatically increased to the maximum values (i.e., 1785 mg/1010 cells and 37 mg C 10−10 cells h−1, respectively). The Ves surface adsorbed Pb cations with higher density, compared with the cell membrane. Moreover, fusion of some Ves to the membrane (functioning in transport) was observed under transmission electron microscope (TEM). Three pathways of detoxification via intracellular Ves were finally proposed, i.e., Ve-mediated transport (from intracellular to extracellular) of EPS components, absorption of Pb NPs on the Ve surface, and accumulation of Pb NPs within Ves. This study sheds light on the possibility of exploring microbial physiology via Pb2+ cations.

23316. 题目: Enhanced high-quality biomethane production from anaerobic digestion of primary sludge by corn stover biochar
文章编号: N20030906
期刊: Bioresource Technology
作者: Wei Wei, Wenshan Guo, Huu Hao Ngo, Giorgio Mannina, Dongbo Wang, Xueming Chen, Yiwen Liu, Lai Peng, Bing-Jie Ni
更新时间: 2020-03-09
摘要: This study conducted batch and continuous tests to reveal the feasibility of corn stover biochar on improving anaerobic digestion of primary sludge (PS). Dosing biochar (1.82, 2.55 and 3.06 g/g Total Solids (TS)) in digester improved methane content increasing from 67.5% to 81.3-87.3% and enhanced methane production by 8.6-17.8%. Model analysis indicated that biochar accelerated PS hydrolysis and enhanced methane potential of PS. The mechanistic studies showed that biochar enhanced process stability provided by strong buffering capacity and alleviated NH3 inhibition. In continuous test over 116 days, the volatile solids (VS) destruction in the biochar-dosed digester increased by 14.9%, resulting in a 14% reduction in the volume of digestate for disposal. Biochar changed microbial community in an expected direction for anaerobic digestion. This work suggests that biochar technology would apply to co-digestion of WAS and PS to maximize the energy recovery and sludge reduction from the two sludge streams.

23317. 题目: Humic acids extracted from compost as amendments for Fenton treatment of diesel-contaminated soil
文章编号: N20030905
期刊: Environmental Science and Pollution Research
作者: Daniela Zingaretti, Miguel Angel Lominchar, Iason Verginelli, Aurora Santos, Renato Baciocchi
更新时间: 2020-03-09
摘要: In this study, we investigate the performance of a Fenton-like process carried out adding as amendments humic acids extracted from compost obtained from organic wastes. Namely, Fenton-like lab-scale tests with different dosages of the extracted humic acids and traditional stabilizing agent (KH2PO4) were performed on a diesel-contaminated soil collected in a former gasoline station. The performed tests showed a beneficial effect of the extracted humic acids on the hydrogen peroxide stability. Namely, the H2O2 lifetime in the tests carried out without the addition of any amendments proved to be quite limited, resulting equal to around 1 h. The adoption of the extracted humic acids alone entailed a limited increase of the hydrogen peroxide stability that anyhow was detected in solution for 24 h using 10 g/L of extracted HA. When the humic acids (10 g/L) were used in combination with KH2PO4 (8.2 g/L), the hydrogen peroxide lifetime increased up to around 150 h. A beneficial effect of the humic acids extracted from compost for a Fenton-like process was also observed in terms of diesel removal. Namely, without any amendment, a contaminant removal of around 55% was observed. Using KH2PO4 or HA alone, the contaminant removal raised up to around 75% while using the traditional stabilizer together with the humic acids extracted from compost, it was possible to remove up to 90% of the initial diesel content of the soil.

23318. 题目: Distribution and transformation behaviors of heavy metals and phosphorus during hydrothermal carbonization of sewage sludge
文章编号: N20030904
期刊: Environmental Science and Pollution Research
作者: Hang Wang, Zijian Yang, Xin Li, Yangsheng Liu
更新时间: 2020-03-09
摘要: This study investigated the distribution and transformation behaviors of heavy metals (HMs) and phosphorus (P) during hydrothermal carbonization (HTC) of sewage sludge. In addition to a large reduction in sludge volume, HTC significantly decreased the exchangeable fraction of HMs (Zn, Cu, Cr, Ni, and Mn) and increased their residual fraction, which resulted in immobilization of HMs accumulated in hydrochar. The ecological toxicity of HMs was greatly reduced, and all HMs exhibited their lowest risk levels after HTC at 220 °C for 1 h in 2% H2SO4 solution. Most of the P (~ 97%) in the input sludge remained in the hydrochar after HTC. HTC facilitated transformation of organic P to inorganic P and promoted conversion of apatite P to non-apatite inorganic P under acidic conditions. The feasibility of recovering P from sludge by HTC was verified by an acid extraction experiment utilizing hydrochar, which recovered more than 90% P.

23319. 题目: A new method for extraction of methanol-soluble brown carbon: Implications for investigation of its light absorption ability
文章编号: N20030903
期刊: Environmental Pollution
作者: Fangping Yan, Shichang Kang, Mika Sillanpää, Zhaofu Hu, Shaopeng Gao, Pengfei Chen, Sangita Gautam, Satu-Pia Reinikainen, Chaoliu Li
更新时间: 2020-03-09
摘要: As an important component of organic carbon (OC), brown carbon (BrC) plays a significant role in radiative forcing in the atmosphere. Water-insoluble OC (WIOC) generally has higher light absorption ability than water-soluble OC (WSOC). The mass absorption cross-section (MAC) of WIOC is normally investigated by dissolving OC in methanol. However, all the current methods have shortcomings due to neglecting the methanol insoluble particulate carbon that is detached from the filter and suspended in methanol extracts, which results in MAC uncertainties of the methanol-soluble BrC and its climate warming estimation. In this study, by investigating typical biomass combustion sourced aerosols from the Tibetan Plateau and ambient aerosols from rural and urban areas in China, we evaluated the light absorption of extractable OC fraction for the existing methods. Moreover, a new method was developed to overcome the methanol insoluble particulate carbon detachment problem to achieve more reliable MAC values. We found that OC can be dissolved in methanol in a short time (e.g., 1 h) and ultrasonic treatment and long-term soaking do not significantly increase the extractable OC fraction. Additionally, we proved that methanol insoluble particulate carbon detachment in methanol does exist in previous methods, causing overestimation of the BrC mass extracted by methanol and thus the underestimation of MAC values. We therefore recommend the newly developed extraction method in this study to be utilized in future related studies to quantitatively obtain the light absorption property of methanol-soluble BrC.

23320. 题目: Significant restructuring and light absorption enhancement of black carbon particles by ammonium nitrate coating
文章编号: N20030902
期刊: Environmental Pollution
作者: Cheng Yuan, Jun Zheng, Yan Ma, Youling Jiang, Yilin Li, Ziqiong Wang
更新时间: 2020-03-09
摘要: Field observations have suggested that particulate nitrate can promote the aging of black carbon (BC), yet the mechanisms of the aging process and its impacts on BC's light absorption are undetermined. Here we performed laboratory simulation of internal mixing of flame-generated BC aggregates with ammonium nitrate. Variations in particle size, mass, coating thickness, effective density, dynamic shape factor, and optical properties were determined online by a suite of instruments. With the development of coatings, the particle size initially decreased until reaching a coating thickness of ∼10 nm and then started increasing, accompanied by an increase in effective density and a decrease in dynamic shape factor, reflecting the transformation of BC particles from highly fractal to near-spherical morphology. This is partially attributable to the restructuring of BC cores to more compact forms. Exposing coated particles to elevated relative humidity (RH) led to additional BC morphology changes, even after drying. Particle light absorption and scattering were also amplified with ammonium nitrate coating, increasing with coating thickness and RH. For BC particles with a 17.8 nm coating, absorption and scattering were increased by 1.5- and 7.9-fold when cycled through 70% RH (5-70-5% RH), respectively. The irreversible restructuring of the BC core caused by condensation of ammonium nitrate and water altered both absorption and scattering, with a magnitude comparable to or even exceeding the effects of increased coating. Results show that ammonium nitrate is among the most efficient coating materials with respect to modifying BC morphology and optical properties compared with other inorganic and organic species investigated previously. Accordingly, mitigation of nitrate aerosols is necessary for the benefits of both air pollution control and reducing the impacts of BC on visibility impairment and radiative forcing on climate change. Our results also pointed out that the effect of BC core restructuring needs to be considered when evaluating BC's light absorption enhancement.