论文检索

总访问量：4705170次

总访客量：218179人

所有论文

23481. 题目: Analysis of the complexation behaviors of Cu(II) with DOM from sludge-based biochars and agricultural soil: Effect of pyrolysis temperature
文章编号: N20022609
期刊: Chemosphere
作者: Jia Xing, Guoren Xu, Guibai Li
更新时间: 2020-02-26
摘要: Pyrolysis temperature is one of the important factors that affect the structure and composition of biochar-derived dissolved organic matter (DOM), which may impact interaction between biochar-derived DOM and Cu(II). Moreover, soil application of biochars pyrolyzed at different temperatures is supposed to cause different complexation behaviors between soils-derived DOM and Cu(II). However, little is known about these aspects. Here, incubation experiments and quenching titration experiments were conducted to explore such pyrolysis temperatures-dependent changes in sludge and sludge-based biochars (SSBA). Two-dimension correlation spectroscopy (2D-COS) indicated humic-like fraction had stronger affinities with Cu(II) in DOM from both sewage sludge (SS) and 500 °C sludge-based biochars (SSB5) while protein-like fraction showed the fastest response to Cu(II) binding in DOM from 300 °C sludge-based biochars (SSB3). One protein-like substance (Component 1) and two humic-like substances (Component 2 and 3) were identified in the DOM derived from SSBA through excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis. Moreover, the Cu(II) complexation affinities of component 1, 2 and 3 decreased from 4.43, 4.53 and 4.86 to 3.26, 3.50 and 3.39 with increasing pyrolysis temperatures, respectively. The addition of 10% SS evidently increased the complexation affinities of humic-like substances in soil-derived DOM from 4.43 to 4.68 to 4.60–6.86, while the complexation affinities of humic-like substances decreased from 4.52 to 4.78 to 3.82–4.50 at a 10% amendment of sludge-based biochars. Compared with sewage sludge, agricultural soil amended with 10% sludge-based biochars had better performance in the aspect of Cu(II) mobility, but had weaker detoxication effect on Cu(II).

23482. 题目: Succession of keratin-degrading bacteria and associated health risks during pig manure composting
文章编号: N20022608
期刊: Journal of Cleaner Production
作者: Yumin Duan, Sanjeev Kumar Awasthi, Tao Liu, Ashok Pandey, Zengqiang Zhang, Sunil Kumar, Mukesh Kumar Awasthi
更新时间: 2020-02-26
摘要: The alteration of microbial dynamics and their divergence were evaluated in bristles containing pig manure (PM) compost with different concentrations of coconut shell biochar [0% (T1), 2.5% (T2), 5.0% (T3), 7.5% (T4) and 10% (T5)] amendment. The results revealed that the CB amendment significantly increased the keratin degradation efficiency and bacterial diversity during composting. The richest bacterial diversity and the highest keratin reduction of 39.1% were observed in the PM compost with a 7.5% CB amendment. The most abundant phyla were Firmicutes and Actinobacteria (which accounted for 87.91% and 12.09%, respectively), and the superior genera were Bacilli and Clostridia (which accounted for 23.52% and 61.17%, respectively). In addition, a dimensionality analysis from principal coordinate's analysis and non-metric multidimensional scaling showed that the bacterial community had a significant divergence among the different dosages of CB. Furthermore, the correlation found in a canonical correspondence analysis illustrated that the physio-chemical environmental factors were more relevant for the bacterial community within the CB in the compost than in that in the control sample. Overall, the application of biochar for composting altered the typical selectivity for functional bacteria and further influenced the organic waste biotransformation during bristle-containing PM composting.

23483. 题目: Controls on the Cd-isotope composition of Upper Cretaceous (Cenomanian–Turonian) organic-rich mudrocks from south Texas (Eagle Ford Group)
文章编号: N20022607
期刊: Geochimica et Cosmochimica Acta
作者: Tim C. Sweere, Alexander J. Dickson, Hugh C. Jenkyns, Don Porcelli, Micha Ruhl, Melissa J. Murphy, Erdem Idiz, Sander H.J.M. van den Boorn, James S. Eldrett, Gideon M. Henderson
更新时间: 2020-02-26
摘要: The isotopic composition of Cd buried in marine sediments may preserve valuable palaeoenvironmental information on past ocean redox conditions or biological cycling. It is unclear, however, how the Cd-isotope composition of the sedimentary record reflects these processes. In this study, new Cd-isotope data are presented, along with δ13C, and Cd, Mo and TOC concentrations, from organic-rich mudrocks from the southern Western Interior Seaway (WIS), spanning the Cenomanian–Turonian stages within the Eagle Ford Group of the Maverick Basin, Texas, USA. Relationships between [Cd/TOC], δ114Cd, and MoEF indicate that sedimentary Cd was derived from organic matter with additional contributions from CdS formed in euxinic water masses. Local redox conditions exerted a primary control on the δ114Cd composition of these deposits, with high δ114Cd values attributed to near-quantitative removal from seawater in euxinic environments. Lower δ114Cd values in non-euxinic environments may reflect isotopically light Cd associated with organic material due to partial remineralization. These observations imply that δ114Cd values of samples deposited in demonstrably euxinic conditions may be used to constrain the δ114Cdseawater coming into the Maverick Basin at this time and give a composition of 0.28 ± 0.11 ‰ (2 SD) for the Early Cenomanian. Samples from an interval of peak-organic carbon burial globally, namely Oceanic Anoxic Event 2 (OAE 2), show anomalous δ114Cd and [Cd] patterns compared to the rest of the data, implying a perturbation to the dissolved Cd pool. The data presented in this study demonstrate that sedimentary Cd isotopes preserve valuable information on the extent of Cd burial into sulfide-bearing sediments at both local and global scales.

23484. 题目: Extrapolation of a structural equation model for digital soil mapping
文章编号: N20022606
期刊: Geoderma
作者: M.E. Angelini, B. Kempen, G.B.M. Heuvelink, A.J.A.M. Temme, M.D. Ransom
更新时间: 2020-02-26
摘要: In theory, two separate regions with the same soil-forming factors should develop similar soil conditions. This theoretical finding has been used in digital soil mapping (DSM) to extrapolate a model from one area to another, which usually does not work out well. One reason for failure could be that most of these studies used empirical methods. Structural equation modelling (SEM) is a semi-mechanistic technique, which can explicitly include expert knowledge. We therefore hypothesize that SEM models are more suitable for extrapolation than purely empirical models in DSM. The objective of this study was to investigate the extrapolation capability of SEM by comparing different model settings. We applied a SEM model from a previous study in Argentina to a similar soil-landscape in the Great Plains of the United States to predict clay, organic carbon, and cation exchange capacity for three major horizons: A, B, and C. We concluded that system relationships that were well supported by pedological knowledge showed consistent and equal behaviour in both study areas. In addition, a deeper understanding of indicators of soil-forming factors could strengthen conceptual models for extrapolating DSM models. We also found that for model extrapolation, knowledge-based links between system variables are more effective than data-driven links. In particular, model modifications can improve local prediction but harm the predictive power of extrapolation.

23485. 题目: Crops for increasing soil organic carbon stocks – A global meta analysis
文章编号: N20022605
期刊: Geoderma
作者: Isack Mathew, Hussein Shimelis, Macdex Mutema, Budiman Minasny, Vincent Chaplot
更新时间: 2020-02-26
摘要: Quantifying the ability of plants to store atmospheric inorganic carbon (C) in their biomass and ultimately in the soil as organic C for long duration is crucial for climate change mitigation and soil fertility improvement. While many independent studies have been performed on the transfer of atmospheric C to soils for single crop types, the objective of this study was to compare the ability of crops, which are most commonly found worldwide, to transfer C to soils, and the associated controlling factors. We performed a meta-analysis of 227 research trials, which had reported C fluxes from plant to soil for different crops. On average, crops assimilated 4.5 Mg C ha−1 yr−1 from the atmosphere with values between 1.7 Mg C ha−1 yr−1, for barley (Hordeum vulgare) and 5.2 Mg C ha−1 yr−1 for maize (Zea mays). Sixty-one percent (61%) of the assimilated C was allocated to shoots, 20% to roots, 7% to soils while 12% was respired back into the atmosphere as autotrophic respiration by plants. Maize and ryegrass (Lolium perenne) had the greatest allocation to the soil (1.0 Mg C ha−1 yr−1 or 19% total assimilation), followed by wheat (Triticum aestivum). 0.8 Mg C ha−1 yr−1, 23%) and rice (Oryza Sativa, 0.7 Mg C ha−1 yr−1, 20%). Carbon allocation to the soil positively correlated to C allocation to roots (r = 0.33, P < 0.05), while correlations between shoot and root biomass on the one hand and C allocation to shoots on the other hand were not significant. The question on the long-term stability of the C transferred to soils remains unanswered.

23486. 题目: Assessing countrywide soil organic carbon stock using hybrid machine learning modelling and legacy soil data in Cameroon
文章编号: N20022604
期刊: Geoderma
作者: Francis B.T. Silatsa, Martin Yemefack, Fritz O. Tabi, Gerard B.M. Heuvelink, Johan G.B. Leenaars
更新时间: 2020-02-26
摘要: Countrywide estimates of soil organic carbon stock (SOCS) are useful to set up national strategies for sustainable land use management as well as to enhance the accuracy of global SOCS inventories. We appraised the spatial distribution of SOCS at five depth layers (0–15 cm, 15–30 cm, 30–100 cm, 0–30 cm and 0–100 cm) in Cameroon at 100 m spatial resolution, using a national harmonized legacy soil database (Camsodat 0.1) with 1432 georeferenced soil profiles. We assessed the prediction performances of random forest (RF) and generalized boosted regression (GBR), combined with two hybridization approaches of spatial interpolation of the residuals using ordinary kriging (OK) and inverse distance weighting (IDW). The estimates were compared to two global estimates derived from the Harmonized World Soil Database (HWSD) and SoilGrids250m. The SOCS distribution across the country showed a moderate spatial heterogeneity at all depth layers with coefficients of variation between 35% and 47%, and values ranging from 6 to 108 Mg C ha−1 at 0–15 cm, from 4 to 107 Mg C ha−1 at 15–30 cm, from 10 to 276 Mg C ha−1 at 30–100 cm, from 11 to 210 Mg C ha−1 at 0–30 cm and from 21 to 468 Mg C ha−1 at the 0–100 cm layer. Of the selected environmental covariates, terrain and climate attributes were the most relevant to predict the SOCS spatial distribution at country level. The RF model outperformed the GBR model, with about 10% improvement on prediction performance (R2) for most soil depths. The hybridization further slightly improved performance. However, OK was only slightly better than IDW in the overall assessment. Compared to national estimates, SoilGrids overestimated the SOCS by 15% at 0–30 cm depth, while HWSD underestimated SOCS by 26% at the same depth. Overall, about 5.7 Pg C are stored in the top 1 m of soils in Cameroon, with about 50% of that in the top 30 cm. The national distribution of SOCS is consistent with the pattern of agro-ecological zones. Our assessment provides baseline information for sustainable land management and climate change mitigation, as well as for improving the understanding of the spatial distribution of SOCS in Cameroon.

23487. 题目: The vital function of humic acid with different molecular weight in controlling Cd and Pb bioavailability and toxicity to earthworm (Eisenia fetida) in soil
文章编号: N20022603
期刊: Environmental Pollution
作者: Hongcheng Bai, Mei Luo, Shiqiang Wei, Zhenmao Jiang, Mingjing He
更新时间: 2020-02-26
摘要: Humic acid (HA) plays vital roles in regulating the environmental behaviors of metals and thus their toxicity to biota. However, the inner relation between metal bioavailability to soil organisms and the presence of HA with different molecular weight (Mw) is not well documented. In this study, we separated HAs into four fractions with Mw range of 5-30k Da, and discussed their ability to alleviating the toxicity of Cd and Pb to earthworm. The bioaccumulation capacities (Cmax) increased in order of: UF1f ) in earthworm bound by Cd and Pb suggested that only free species of Cd could be considered as biological available to earthworm, while the Pb–HAs complexes have potential ability to interact with earthworm membrane. Antioxidant enzymes are effective biomarkers, and HA with lower Mw play more important roles in restricting the toxicity of soil Cd and Pb to earthworm. These results reveal the different mechanism for HA controlling metal bioavailability between Cd and Pb in soil environment.

23488. 题目: Warming the phycosphere: differential effect of temperature on the use of diatom‐derived carbon by two copiotrophic bacterial taxa
文章编号: N20022602
期刊: Environmental Microbiology
作者: Nestor Arandia‐Gorostidi, Laura Alonso‐Sáez, Hryhoriy Stryhanyuk, Hans H. Richnow, Xosé Anxelu G. Morán, Niculina Musat
更新时间: 2020-02-26
摘要: Heterotrophic bacteria associated with microphytoplankton, particularly those colonizing the phycosphere, are major players in the remineralization of algal‐derived carbon. Ocean warming might impact DOC uptake by microphytoplankton‐associated bacteria with unknown biogeochemical implications. Here, by incubating natural seawater samples at 3 different temperatures we analyzed the effect of experimental warming on the abundance and C and N uptake activity of Rhodobacteraceae and Flavobacteria, two bacterial groups typically associated with microphytoplankton. Using NanoSIMS single‐cell analysis we quantified the temperature‐sensitivity of these two taxonomic groups to the uptake of algal‐derived DOC in the microphytoplankton‐associated fraction with 13C‐bicarbonate and 15N‐leucine as tracers. We found that cell‐specific 13C uptake was similar for both groups (~0.42 fg C h−1 μm−3), but Rhodobacteraceae were more active in 15N‐leucine uptake. Due to the higher abundance of Flavobacteria associated with microphytoplankton, this group incorporated 4‐fold more carbon than Rhodobacteraceae. Cell‐specific 13C uptake was influenced by temperature, but no significant differences were found for 15N‐leucine uptake. Our results show that the contribution of Flavobacteria and Rhodobacteraceae to C assimilation increased up to 6‐fold and 2‐fold, respectively, with an increase of 3°C above ambient temperature, suggesting that warming may differently affect the contribution of distinct copiotrophic bacterial taxa to carbon cycling. This article is protected by copyright. All rights reserved.

23489. 题目: Impact of sediment characteristics on adsorption behavior of typical antibiotics in Lake Taihu, China
文章编号: N20022601
期刊: Science of The Total Environment
作者: Yuqi Huang, Yue Wang, Yuzhou Huang, Lixuan Zhang, Fan Ye, Jinling Wang, Jingge Shang, Qianjiahua Liao
更新时间: 2020-02-26
摘要: Sediment adsorption is one of the main fates of antibiotics in aquatic environments. However, few studies have compared the physicochemical properties of sediments from the same aquatic ecosystem but at different locations and correlated them with antibiotic adsorption efficiency. To predict the adsorption of antibiotics in water–sediment systems more accurately, this study conducted experiments with tetracycline (TC) and oxytetracycline (OTC) in tetracyclines, ciprofloxacin (CIP) in fluoroquinolones, and roxithromycin (ROX) in macrolides. Sediments from different locations in Lake Taihu, China, were collected to determine the adsorption properties of CIP, TC, OTC, and ROX. Moreover, the physicochemical properties of the sediments were measured and the correlation between these properties and antibiotic adsorption were discussed to establish a model for predicting adsorption parameter Kd. The antibiotic adsorption performance of sediments was high in heavily polluted and grassy areas but poor in estuarine areas of the lake, suggesting that adsorption effectiveness was affected by the physicochemical properties of sediments. Based on the established model, the specific surface area, organic carbon, and cation exchange capacity played the most significant roles. The study further determined that the predicted and actual values showed a good linear fitting relationship. Therefore, the model effectively predicted the antibiotic adsorption performance of different sediments and provided recommendations for the environmental trend and risk assessment of antibiotics.

23490. 题目: Basal thermal regime affects the biogeochemistry of subglacial systems
文章编号: N20022505
期刊: Biogeosciences
作者: Ashley Dubnick, Martin Sharp, Brad Danielson, Alireza Saidi-Mehrabad, Joel Barker
更新时间: 2020-02-25
摘要: Ice formed in the subglacial environment can contain some of the highest concentrations of solutes, nutrients, and microbes found in glacier systems, which can be released to downstream freshwater and marine ecosystems and glacier forefields. Despite the potential ecological importance of basal ice, our understanding of its spatial and temporal biogeochemical variability remains limited. We hypothesize that the basal thermal regime of glaciers is a dominant control on subglacial biogeochemistry because it influences the degree to which glaciers mobilize material from the underlying substrate and controls the nature and extent of biogeochemical activity that occurs at glacier beds. Here, we characterize the solutes, nutrients, and microbes found in the basal regions of a cold-based glacier and three polythermal glaciers and compare them to those found in overlying glacier ice of meteoric origin. Compared to meteoric glacier ice, basal ice from polythermal glaciers was consistently enriched in major ions, dissolved organic matter (including a specific fraction of humic-like fluorescent material), and microbes and was occasionally enriched in dissolved phosphorus and reduced nitrogen (NH + 4 ) and in a second dissolved component of humic-like fluorescent material. In contrast, the biogeochemistry of basal ice from the cold-based glacier was remarkably similar to that of meteoric glacier ice. These findings suggest that a glacier's basal thermal regime can play an important role in determining the mix of solutes, nutrients, and microbes that are acquired from subglacial substrates or produced in situ.

23491. 题目: Iron–electrocoagulation as a disinfection byproduct control strategy for drinking water treatment
文章编号: N20022504
期刊: Environmental Science: Water Research & Technology
作者: Donald R. Ryan, Patrick McNamara, Brooke K Mayer
更新时间: 2020-02-25
摘要: Disinfection byproducts (DBPs) result from reactions between oxidizing disinfectants, e.g., free chlorine, and DBP precursors such as natural organic matter (NOM). Electrocoagulation (EC) has potential as an effective DBP precursor removal strategy for decentralized water treatment and small drinking water utilities as it features similar removal trends compared to conventional coagulation, without alkalinity consumption, while also generating coagulant in situ by anodic dissolution of iron electrodes. However, studies assessing DBP formation in drinking water following EC treatment are lacking. This research evaluated EC as a DBP precursor removal strategy by quantifying reductions in total trihalomethane (TTHM) formation potential as a function of electrolysis time (2.5 – 17.5 min), pH (6 - 9.1), and the type of NOM treated (5 – 9.1 mg-C/L spiked as humic acid, fulvic acid, or NOM, or initially present in the Milwaukee River). Using doses of approximately 35 mg-Fe/L, EC performed similarly to conventional coagulation when the water matrices were at the same pH. As pH decreased, shorter EC electrolysis times were needed to decrease TTHM formation potential to meet the U.S. Environmental Protection Agency maximum contaminant level for TTHMs. EC decreased the mean specific TTHM formation potential (µg-TTHM/mg-C) of every NOM source, thereby demonstrating that the residual NOM following EC treatment formed less DBPs per unit carbon compared to the influent water.

23492. 题目: Production of ancient dissolved organic carbon in Arctic Ocean sediment: A pathway of carbon cycling in the extreme environment
文章编号: N20022503
期刊: Geophysical Research Letters
作者: Wenjing Fu, Yuanzhi Qi, Yanguang Liu, Xuchen Wang, Ellen M. Druffel, Xiaomei Xu, Peng Ren, Shuwen Sun, Di Fan
更新时间: 2020-02-25
摘要: We report quantitative carbon isotope evidence showing that porewater dissolved organic carbon (DOC) is produced from different sources in Arctic Ocean sediments, resulting in dramatic changes in both δ¹³C and Δ¹⁴C values of DOC. The very low δ¹³C (‐42.7‰) and Δ¹⁴C (‐947‰) values measured for porewater DOC indicate that bacteria consume methane hydrate‐derived OC and convert a significant fraction of this δ¹³C‐depleted and old OC (44‐97%) into DOC in the sediments of the Arctic Ocean. We suggest that the production of extremely old, methane‐derived porewater DOC (5,430‐23,600 years) in Arctic Ocean sediment is an important pathway for carbon cycling that provides not only a necessary energy source for microbial communities in this extreme environment but also an ancient DOC source that could flux and contribute to the old and biologically recalcitrant DOC found in the deep ocean.

23493. 题目: A rapid hydroclimate change and its influence on the Songliao Basin during the Santonian-Campanian transition as recorded by compound-specific isotopes
文章编号: N20022502
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Li Wang, Yankuan Tian, Jiaju Zhao
更新时间: 2020-02-25
摘要: Reconstruction of the paleoclimate and paleoenvironment of the Songliao Basin has important theoretical and practical significance to reveal the regional continental climate characteristics and continental organic matter accumulation under the Cretaceous greenhouse climate conditions. Here, we report the composition of biomarkers and the stable carbon and hydrogen isotope compositions of n-alkanes from Nenjiang Formation sediments in the Songliao Basin, which provide information on the source of organisms, paleoenvironmental conditions, and paleoclimate changes during the Late Cretaceous. Our hydrogen isotope records of n-alkanes displayed a significantly negative shift, indicating that a dramatically wet climate occurred during the Santonian-Campanian transition. A wet climate, such as that during a prolonged rainfall event, had a significant impact on the lake and resulted in the lake level increasing and the salinity decreasing in the surface water during this period. However, the freshwater input increased the salinity difference between the upper and lower water layers, which caused stable water stratification to occur in the lake. In addition, the high total organic carbon (TOC) content indicates high primary productivity because of increased precipitation carrying more terrigenous nutrients into the lake, which resulted in eutrophication during this period. Notably, the increased aryl isoprenoid ratios and the occurrence of isorenieratane indicates that photic zone euxinia (PZE) was enhanced during the Santonian-Campanian transition, which was possibly due to the dramatic change in the hydroclimate. We speculate that the large freshwater input promoted the formation of PZE in the lake. Then, PZE restricted the habitat available for aerobic organisms, which had fatal effects on the lake ecosystem.

23494. 题目: Photocatalytic degradation of organic micropollutants: Inhibition mechanisms by different fractions of natural organic matter
文章编号: N20022501
期刊: Water Research
作者: Dion Awfa, Mohamed Ateia, Manabu Fujii, Chihiro Yoshimura
更新时间: 2020-02-25
摘要: Natural organic matter (NOM) can inhibit the photocatalytic degradation of organic micropollutants (OMPs) through inner filter effect, reactive oxygen species (ROS) scavenging, and competitive adsorption. However, previous studies have focused solely on the bulk properties of NOM and our understanding of the inhibition mechanism by NOM fractions during photocatalytic degradation of OMP is still fragmentary. In this study, five well-characterized different NOM samples (i.e., secondary treated wastewater, river water, and three standard NOM surrogates) were used to elucidate the inhibition mechanisms during photocatalytic degradation of carbamazepine (a model OMP) using TiO₂ and its composites with carbon nanotubes (CNT-TiO₂) under UVC and solar-light irradiation. The results indicated that terrestrially derived NOM with high aromaticity, a low oxygen/carbon atom ratio, and large molecular weight is the major fraction that participates in ROS scavenging, competitive adsorption, and inner filter effect. Furthermore, the modeling analysis suggested that inner filter effect due to NOM and ROS scavenging was the most influential inhibitory mechanism. In the case of secondary treated wastewater, the presence of high concentrations of inorganic species (e.g., PO₄³⁻, Cl⁻, and NO₃⁻) together with NOM significantly reduced the photocatalytic degradation of carbamazepine. Overall, the methods and the results of this study provide a comprehensive understanding of the effects of NOM fractions on photocatalysis and highlight the need to further consider the interplay between NOM and background inorganic constituents in photocatalytic degradation of OMP.
图文摘要:

23495. 题目: Contribution of different iron species in the iron-biochar composites to sorption and degradation of two dyes with varying properties
文章编号: N20022402
期刊: Chemical Engineering Journal
作者: Yewen Qiu, Xiaoyun Xu, Zibo Xu, Jun Liang, Yulu Yu, Xinde Cao
更新时间: 2020-02-24
摘要: Iron-modified biochar has been demonstrated as an effective sorbent for the removal of aqueous organic contaminants. However, the effects of different iron species in the iron-biochar composites on the sorption and degradation of organic contaminants remain unclear. In this study, the iron-biochar composites containing different iron species were produced by one-pot pyrolysis of peanut shell with Fe₂O₃ at 400 °C and 700 °C, and then were used to remove two model dyes of different properties, methylene blue (MB) and acid orange 7 (AO7). The main Fe species in the biochar composites generated at 400 °C were Fe₂O₃, Fe₃O₄, FeO, and Fe⁰, while Fe₃O₄, FeO, and Fe⁰ were dominant in the biochar composites produced at 700 °C. Compared to the pristine biochar, the iron-biochar composites possessed higher ability to remove both MB and AO7 with the removal efficiency increasing from 33%–72% to 48%–92% and from 49%–70% to 72%–85%, respectively. The removal efficiency increased as Fe contents increased and biochar produced at 400 °C was more effective in removing MB and AO7 than biochar produced at 700 °C. Fe₂O₃, Fe⁰, and Fe³⁺ facilitated the degradation of MB, while FeO, Fe⁰, and Fe³⁺ had significant positive impact on AO7 degradation. The degradation was more obvious than sorption in MB removal by the biochar composites, while the opposite trend was observed for the removal of AO7. Degradation of MB by iron-biochar composites underwent the aromatic ring cleavage and oxidation, whereas hydroxylation, oxidization and decarboxylation were found in AO7 degradation. This study indicated that the iron-biochar composites were effective in removing the dyes and iron species played important roles in the dye removal.
图文摘要:

23496. 题目: Phosphorus recovery from the liquid phase of anaerobic digestate using biochar derived from iron−rich sludge: A potential phosphorus fertilizer
文章编号: N20022401
期刊: Water Research
作者: Hui Wang, Keke Xiao, Jiakuan Yang, Zecong Yu, Wenbo Yu, Qi Xu, Qiongxiang Wu, Sha Liang, Jingping Hu, Huijie Hou, Bingchuan Liu
更新时间: 2020-02-24
摘要: A novel technique for phosphorus recovery from the liquid phase of anaerobic digestate was developed using biochar derived from iron−rich sludge (dewatered sludge conditioned with Fenton's reagent). The biochar pyrolyzed from iron−rich sludge at a low temperature of 300 °C (referred to as Fe−300 biochar) showed a better phosphorus (P) adsorption capacity (most of orthophosphate and pyrophosphate) than biochars pyrolyzed at other higher temperatures of 500–900 °C, with the maximum P adsorption capacity of up to 1.843 mg g⁻¹ for the liquid phase of anaerobic digestate. Adsorption isotherms study indicated that 70% P was precipitated through chemical reaction with Fe elements, i.e., Fe(II) and Fe(III) existed on the surface of the Fe−300 biochar, and other 30% was through surface physical adsorption as simulated by a dual Langmuir-Langmuir model using the potassium dihydrogen orthophosphate (KH₂PO₄) as a model solution. The seed germination rate was increased up to 92% with the addition of Fe−300 biochar after adsorbing most of P, compared with 66% without the addition of biochar. Moreover, P adsorbed by the chemical reaction in form of iron hydrogen phosphate can be solubilized by a phosphate-solubilizing microorganism of Pseudomonas aeruginosa, with the total solubilized P amount of 3.045 mg g⁻¹ at the end of an incubation of 20 days. This study indicated that the iron−rich sludge−derived biochar could be used as a novel and beneficial functional material for P recovery from the liquid phase of anaerobic digestate. The recovered P with biochar can be re-utilized in garden soil as an efficient P−fertilizer, thus increasing the added values of both the liquid phase of anaerobic digestate and the iron−rich sludge.
图文摘要:

23497. 题目: Utilization of biochar for the removal of nitrogen and phosphorus
文章编号: N20022313
期刊: Journal of Cleaner Production
作者: Yingjie Dai, Wensi Wang, Lu Lu, Lilong Yan, Dianyu Yu
更新时间: 2020-02-23
摘要: In recent years, excessive amounts of nitrogen (N) and phosphorus (P) in the environment have seriously affected the environment and human health. Due to its high removal efficiency, high flexibility and good economic and environmental benefits, biochar (BC) is a stable carbon-rich product formed by thermal decomposition of biomass such as agricultural and forestry wastes under anoxic conditions. The fine pore structure of the original material has strong adsorption capacity, low solubility, stable physical and chemical properties, rich pore structure, and large specific surface area. BC can be made from any organic material, common raw materials are rice husk, straw, animal manure, sewage sludge and some other agricultural wastes. It has received widespread attention as an adsorbent that efficiently adsorbs and removes N and P. It can not only be used to control environmental pollution, but also has a good application prospect in soil improvement and engineering treatment. If it is widely used in engineering, its expected effect will be beneficial to the overall environment. At present, the number of review articles in this area is relatively small. In order for scholars to understand the research progress in this area more conveniently and quickly, through a lot of literature review and summary, this article summarizes the research status of BC on N and P adsorption, and elaborates. The influence factors and adsorption mechanism of N and P were introduced, the application of N and P adsorbed by BC as fertilizer in soil was introduced, the application of BC in engineering treatment was introduced, and the economic and environmental benefits of BC were analyzed. After summarizing the current findings, we explore the future development of BC's adsorption of N and P and issues that need to be considered in the future development process. It is expected that this systematic review will help other interested researchers to participate in further exploration of this research area.

23498. 题目: Soil organic matter and silt contents determine soil particle surface electrochemical properties across a long-term natural restoration grassland
文章编号: N20022312
期刊: CATENA
作者: Jingfang Liu, Zilong Wang, Feinan Hu, Chenyang Xu, Rentian Ma, Shiwei Zhao
更新时间: 2020-02-23
摘要: Vegetation restoration is an effective way to rebuild degraded ecosystems and restore soil function. Soil surface electrochemical properties, including specific surface area, cation exchange capacity, surface charge density, surface electric field strength, and surface potential, are often used as indicators to evaluate agricultural soil quality and fertility. However, little attention has been payed to the effect of natural revegetation on soil surface electrochemical properties. In this work, we selected a grassland restoration chronosequence (slope cropland, 0 years; natural grasslands restored for 3, 8, 22 and 24 years, i.e. NR3, NR8, NR22 and NR24, respectively) to investigate the changes of soil surface electrochemical properties along with vegetative restoration. Our results showed that surface charge density and surface potential for restored grassland ranged from 0.16 to 0.20 C m⁻² and from −94 to −109 mV, with an average of 0.18 C m⁻² and −101 mV, respectively. The value of surface electric field strength could reach to the order of magnitude of −10⁷ V m⁻¹ and showed a decreasing trend with increasing period of natural vegetation recovery. Cation exchange capacity and specific surface area significantly increased with the extension of natural restoration period except for NR3 (P < 0.05). It was found that soil organic matter (SOM) and silt content were the main factors to determine cation exchange capacity and specific surface area. Both cation exchange capacity and specific surface area were closely related to silt content but weakly related to clay content, possibly due to the high silt content in our studied soils. Moreover, cation exchange capacity and specific surface area showed a significant linear relationship with SOM, which may be ascribed to the diversity in cation substitution sites and high specific surface area of SOM. Our results indicated that the long-term natural restoration of grassland contributed to the improvement of cation exchange capacity and specific surface area.

23499. 题目: Novel Fe-Mn binary oxide-biochar as an adsorbent for removing Cd(II) from aqueous solutions
文章编号: N20022311
期刊: Chemical Engineering Journal
作者: Guangcai Yin, Xiaowang Song, Lin Tao, Binoy Sarkar, Ajit K Sarmah, Wenxiang Zhang, Qintie Lin, Rongbo Xiao, Qianjun Liu, Hailong Wang
更新时间: 2020-02-23
摘要: In this study, a pristine biochar (BC) and Fe-Mn binary oxide-biochar (FMBC) were prepared using Pennisetum sp. straw as the feedstock for Cd(II) removal from aqueous solutions. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and specific surface area (SSA) analyses revealed the physico-chemical characteristics of the pristine and designer adsorbents, suggesting that an ultrasonic treatment during synthesis enhanced the SSA and pore volume of the BC, and assisted successful loading of Fe-Mn binary oxide particles on the BC surface. The Cd(II) adsorption data of the adsorbents were fitted to the Langmuir isothermal and pseudo-second-order kinetic models. At a system temperature of 25 °C and pH 5, the maximum Cd(II) adsorption capacities of BC (30.58 mg/g) and FMBC (95.23 mg/g) were obtained. Multiple Cd(II) adsorption mechanisms by FMBC were identified, including precipitation with minerals, complexation with surface functional groups, Cd(II)-π interactions, and cation exchange. As the most dominant adsorption mechanism, Cd-O bonds were formed on the FMBC surfaces precipitating Cd(OH)₂ (63.9 wt%) and CdO (36.1 wt%). The FMBC thus could be potentially used as an effective adsorbent for Cd(II) removal from aqueous solutions.
图文摘要:

23500. 题目: Advanced treatment of bio-treated Chinese patent medicine wastewater using ozone/peroxymonosulfate-upflow biological aerated filter
文章编号: N20022310
期刊: Chemical Engineering Journal
作者: Guomin Tang, Yongbing Zhang, Yujiang Wei, Shuang Wang, Pei Liu, Zhehua Jia, Xuemin Yu, Fang Ma
更新时间: 2020-02-23
摘要: The advanced treatment of biotreated Chinese patent medicine wastewater (BCPMW) was urgently necessitated to meet the strictest wastewater discharge standard. In the present study, combined ozone/peroxymonosulfate oxidation and upflow biological aerated filter process (O₃/PMS-UBAF) significantly integrated advantages of O₃/PMS oxidation and UBAF, and has been demonstrated to be very effective in the advanced treatment of BCPMW. For dissolved organic matter (DOM) in BCPMW, O₃/PMS oxidation efficiently degraded higher molecular weight (MW) fractions and non-biodegradable fractions. In addition, O₃/PMS oxidation not only increased the overall removal of DOM but also enhanced the biodegradation rate of DOM. Therefore, the beneficial effect of O₃/PMS oxidation may mainly be due to the special effect of increased biodegradability and the generalized effect on DOM. Finally, the results also indicated that compared with UBAF alone, O₃/PMS-UBAF not only promoted the removal of low MW fractions (＜3kDa) but also inhibited the formation of higher MW fractions (3-10 kDa) that was generated by UBAF alone.