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25741. 题目: Box-Behnken response surface approach to identify factors affecting membrane fouling in a hybrid membrane bioreactor treating domestic sewage
文章编号: N19121809
期刊: Environmental Science and Pollution Research
作者: Ying Li, Wei Chen, Xiao-Ying Zheng, Qiang Liu, Wei Xiang, Ji-Xiang Qu
更新时间: 2019-12-18
摘要: The effect of hydraulic retention time (HRT) and sludge retention time (SRT) on extracellular polymer substrate (EPS) content and resistance of a hybrid membrane bioreactor (HMBR) treating domestic sewage was analyzed by Box-Behnken response surface methodology. The quadratic response surface model demonstrated significant effects of both HRT and SRT on EPS content (both P value < 0.05), SRT on membrane resistance (P value = 0.0119), and their interaction was significant (P value = 0.0273) for EPS but not membrane resistance (P value = 0.0609). Model optimization indicates that the optimal conditions for the HMBR to control membrane fouling were an HRT of 10 h and SRT of 30 days. Under these optimal conditions, both the EPS content and the predicted membrane resistance closely matched the actual average value with the error about 8%. Thus, the feasibility of applying response surface methodology to an HMBR for treating domestic sewage was demonstrated. According to the detection result of the three-dimensional fluorescence (excitation-emission matrix), humic acid-like and fulvic acid-like substances gain much higher levels in the suspended carriers than those in the membrane and sludge, suggesting that these are key components of the membrane pollutants.

25742. 题目: Biochars derived from crop straws increased the availability of applied phosphorus fertilizer for maize in Ultisol and Oxisol
文章编号: N19121808
期刊: Environmental Science and Pollution Research
作者: M. Abdulaha-Al Baquy, Jun Jiang, Renkou Xu
更新时间: 2019-12-18
摘要: The extensive use of phosphorus (P) fertilizer is a common practice due to the suboptimal P in variable charge soils for better crop growth. The aim of this study was to increase our understandings and disclose the mechanisms for increase in P availability in Ultisol and Oxisol by biochars derived from crop straws. Incubation and greenhouse pot experiments were conducted to attain the objective. Results from incubation study indicated that biochars derived from different crop straws increased P recovery in both Ultisol and Oxisol. Biochars increased the repulsion of soil surface to phosphate (PO₄³⁻) anions due to increased soil CEC, and thus increased P recovery; acidic functional groups on biochars competed for soil sorption sites with PO₄³⁻, and thus increased P recovery. While the formation of insoluble PO₄³⁻ with divalent cations of calcium (Ca) and magnesium (Mg) from the biochars reduced P recovery. P recovery was increased with increasing soil pH and biochar application rate for each biochar type. The lower content of Ca²⁺ and Mg²⁺ in rice straw biochar led to greater increase in P recovery than canola and peanut straw biochars. When two soils were compared with each other, P recovery was higher in Ultisol than Oxisol due to the presence of large amount of Fe and Al oxides in Oxisol. Results from pot experiment showed that plant dry matter yield and P recovery by maize were increased with increasing rate of rice straw biochar applied over control. Therefore, application of P fertilizer in rice straw biochar–amended soils will increase P availability to crops and thus crop yields in variable charge soils.

25743. 题目: Enhanced removal of aqueous Cr(VI) by a green synthesized nanoscale zero-valent iron supported on oak wood biochar
文章编号: N19121807
期刊: Chemosphere
作者: Yuting Zhang, Xinqian Jiao, Na Liu, Jing Lv, Yadong Yang
更新时间: 2019-12-18
摘要: Green nanoscale zero iron (nZVI) on an oak wood biochar support was prepared from tea polyphenol (TP–nZVI–OB), and applied to the removal of hexavalent chromium (Cr(VI)) from aqueous solution. The effects of experimental parameters on the Cr(VI) removal were evaluated by varying the Fe/C mass ratio, contact time, initial pH, and initial Cr(VI) concentration. The Cr(VI) removal performance of the TP–nZVI–OB was optimized at an Fe/C mass ratio of 2:1. The initial pH significantly affected the Cr(VI) removal, and 99.9% of the Cr(VI) was eliminated at pH 2.0. The kinetic data were well fitted to a pseudo-second order model, indicating that Cr(VI) removal was dominated by chemisorption. The successful TP–nZVI–OB synthesis and effective Cr(VI) removal mechanisms were confirmed by multiple techniques. The reaction between Cr(VI) and TP–nZVI–OB (2:1) involved multiple processes (sorption, reduction and co-precipitation), clarifying that TP–nZVI–OB is a potentially superior composite for Cr(VI) treatment of contaminated aqueous solution.
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25744. 题目: Recovery of efficient treatment performance in a semi-aerobic aged refuse biofilter when treating landfill leachate: Washing action using domestic sewage
文章编号: N19121806
期刊: Chemosphere
作者: Weiming Chen, Fan Wang, Zhepei Gu, Qibin Li
更新时间: 2019-12-18
摘要: Semi-aerobic aged refuse biofilters (SAARB) are known to efficiently remove organic matter, nitrogenous substances, and anions from landfill leachate. However, long-term recirculation of mature landfill leachate inevitably leads to accumulation of pollutants and decreases treatment capacity. In this study, the washing action provided by domestic sewage was used to recover and even enhance the treatment performance of SAARBs treating mature landfill leachate. Three SAARB columns were operated for 300 d after which a “Recirculation-Washing-Recirculation” sequence was followed. In the first recirculation period (22 d), removal of chemical oxygen demand (COD) and total nitrogen (TN) decreased from ca. 90% and 60%, respectively, initially to about 75% and less than 20%, respectively. Thereafter, washing (20 d) of the SAARBs was accomplished by applying domestic sewage. In the subsequent second recirculation period (30 d), the SAARBs were operated at the same hydraulic loading as used initially, but achieved high (ca. 90%) COD and relatively high (ca. 59%–76%) TN removal, including degradation of refractory organic matter such as humic- and fulvic-like substances. Overall, the mechanisms of the treatment performance recovery (including organics degradation and nitrification-denitrification) using domestic sewage can be attributed to three main effects: (1) some accumulated pollutants were washed out, thereby leading to recovery of the adsorption ability of aged refuse; (2) the inhibition of bio-refractory organics stress on microbial activities was mitigated by domestic sewage washing; and (3) the wash out of some accumulated salts (e.g., chloride and sulfate ions) probably helped the microbial activity recover.

25745. 题目: Controlling factors and environmental significance of BIT and δ¹³C of sedimentary GDGTs from the Pearl River Estuary, China over recent decades
文章编号: N19121805
期刊: Estuarine, Coastal and Shelf Science
作者: Shendong Xu, Zhinan Zhang, Guodong Jia, Kefu Yu, Fei Lei, Xiaowei Zhu
更新时间: 2019-12-18
摘要: The Pearl River Delta region has become one of the fastest developing regions in China in recent decades. As a result, large volumes of nutrients and carbon have been delivered to the Pearl River Estuary (PRE), causing eutrophication over the past century. In this study, four sediment cores were collected, they were analyzed for branched and isoprenoid tetraether lipids, total organic carbon content (TOC), total carbon to nitrogen (TOC/TON) ratio and δ¹³C values of crenarchaeol-derived biphytanes (δ¹³C_BP-Cren) after ether cleavage of isoprenoid glycerol dialkyl glycerol tetraether lipids (iGDGT's). The purpose of this study is to analyze the controlling factors and environmental significance of the BIT index (a paleoproxy based on concentrations of branched and isoprenoid tetraether lipids) and δ¹³C_BP-Cren values, and then to explore the possible responses of the BIT index and δ¹³C_BP-Cren values to increasingly eutrophication (i.e., frequent outbreaks of algal blooms) occurring near the PRE in recent decades. The BIT index exhibits a decreasing trend in cores off the PRE (A8 and A9), indicating there was an increasing relative contribution of marine-derived organic carbon to the TOC content in the sediment. The δ¹³C values of all four core records exhibit decreasing trends toward the present day, exhibiting the influence of the Suess effect. However, the rates of δ¹³C_BP-Cren reduction are lower in cores A8 and A9 that are close to the PRE, than those in cores that are more offshore (E501 and LE01, east of Hainan Island). In particular, the decrease in δ¹³C_BP-Cren with time in cores A8 and A9 effectively stopped after the 1970s, but continued to occur in cores collected from east of Hainan Island. This may be mainly caused by the reduced riverine input of GDGT's and increasing eutrophication. The relative proportion of riverine Thaumarchaeota (with more negative δ¹³C values) decreased off the PRE, leading to the δ¹³C_BP-Cren values of cores here being more positive. Furthermore, the declining trend of δ¹³C_BP-Cren values (in response to the Suess effect) in cores A8 and A9 off the PRE may be partially offset by increasing water productivity. This study indicates that the BIT index and δ¹³C_BP-Cren values in estuarine sediments were affected by variation in both riverine input of GDGT's and surface water productivity. As a result, the BIT index and δ¹³C_BP-Cren in estuarine sediments may represent potential proxies for past changes in eutrophication in estuaries.

25746. 题目: Exploring the effect of varying soil organic matter contents on current and future moisture supply capacities of six Italian soils
文章编号: N19121804
期刊: Geoderma
作者: Antonello Bonfante, A. Basile, J. Bouma
更新时间: 2019-12-18
摘要: The Available Soil Water Capacity (AWC) is standard data in most soil databases and expresses soil water contents in the rootzone between field capacity (FC; –33 kPa) and permanent wilting point (WP; −1500 kPa). Literature suggests that increasing the content of soil organic matter (SOM) of a given soil does not significantly increase AWC and this has important implications when estimating soil moisture supply to crops and evaluating the potential for climate mitigation. For most crops, the real FC values vary between −10 and −50 kPa in different soils and WP values between −800 and −1500 kPa. Thus standard values for AWC of FC and WP do not represent field conditions in many soils. When exploring AWC for six Italian soil series, ranging from clay to sandy, AWC values at increasing %SOM were lower in clay soils and higher in sand as compared with actual conditions, which could be explained by considering the shape of the corresponding moisture retention curves. Rather than focus on static AWC values to define moisture supply to plants, real or actual soil moisture supply capacities (MSC) can be obtained by dynamic modeling of the soil-water-atmosphere-plant system, including a “sink-term” indicating a continuous relation between water uptake and negative pressure head of soil water and evaporative demand. Also, only models allow exploration of the effects of future severe IPCC climate scenario RCP 8.5. Thus, studying MSC for the six Italian soil series showed that MSC values were: (i) on average 30% higher than the corresponding AWC; (ii) distinctly different for the six soils; (iii) affected by declines of 1–9% as a result of the effects of future climate scenarios.; (iv) not significantly affected by increases of %SOM when considering climate change, except for the sand. Generalizations as to the effect of future climate scenarios and %SOM on MSC can only be realistic when modeling is performed for soil series in different climate zones.

25747. 题目: Electrochemical evaluation of iron-binding ligands along the Australian GEOTRACES southwestern Pacific section (GP13)
文章编号: N19121803
期刊: Marine Chemistry
作者: Damien J.E. Cabanes, Louiza Norman, Andrew R. Bowie, Slađana Strmečki, Christel S. Hassler
更新时间: 2019-12-18
摘要: In this work, we performed electrochemical investigations of Fe-binding ligands in water samples collected in autumn 2011 along the Australian GEOTRACES southwestern Pacific section (GP13, between 153°E and 170°W longitude along the 30°S line East of Australia, 0-1000 m depth). We determined the capacity of the bulk organic ligands to complex Fe using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-AdCSV) with salicylaldoxime as the competing ligand. Two categories of organic ligands, humic substances (HS-like) and catalytically active polymers (Cat. P) were electrochemically quantified in order to better define the bulk of Fe-binding ligands. Finally, Fe speciation results have been linked to oceanographic data, phytoplankton biomass, and two groups of cyanobacteria (Prochlorococcus and Synechococcus) which are prominent members of the phototrophic community in the study region. Across the section, higher total ligand concentrations over dissolved Fe concentrations were observed, as well as the predominance of “weak” Fe-binding ligands (log K’_Fe’L < 12). Highest “excess ligands” were mostly concentrated in the upper layer of the water column, suggesting a direct link with biological activity. None of the two groups of organic ligands measured (HS-like and Cat. P) accounted for the bulk of the total Fe-binding ligands concentration, hindering a better characterization of the nature of in-situ Fe-binding ligands. Cat. P concentrations showed statistically significant positive correlations with all biomarker pigments and the abundance of Prochlorococcus, suggesting that this material, resembling polysaccharides, could be a good parameter to probe organic compounds from specific biological origin. Amongst the biological parameters, only Prochlorococcus was related to Fe’ concentrations.

25748. 题目: Adsorption/desorption of sulfamethoxypyridazine and enrofloxacin in agricultural soils
文章编号: N19121802
期刊: Science of The Total Environment
作者: C. Álvarez-Esmorís, M. Conde-Cid, G. Ferreira-Coelho, M.J. Fernández-Sanjurjo, A. Núñez-Delgado, E. Álvarez-Rodríguez, M. Arias-Estévez
更新时间: 2019-12-18
摘要: Adsorption and desorption processes were studied for the antibiotics sulfamethoxypyridazine (SMP) and enrofloxacin (ENR) in 20 agricultural soils devoted to wheat-potato and vine cultivation. Batch experiments were used to conduct kinetic studies, as well as to evaluate adsorption and desorption for different concentrations of antibiotics. The results indicated that adsorption curves were linear for SMP, while presented a certain curvature in the case of ENR. The adsorption of both antibiotics was fitted to a linear equation and to the Freundlich model. In the case of the linear equation, the values of the distribution coefficient K_d were lower for SMP (0.9–26.0 L kg⁻¹) than for ENR (121–2345 L kg⁻¹). In the Freundlich model, the values of the adsorption constant K_F ranged between 1.7 and 34.0 Lⁿ μmol¹⁻ⁿ kg⁻¹ for SMP, and between 829 and 3019 Lⁿ μmol¹⁻ⁿ kg⁻¹ for ENR. A multiple regression analysis showed that, in the case of SMP, 78% of the variance of the adsorption parameter K_d was explained by soil organic carbon (SOC) and exchangeable magnesium (Mg_e) contents, while for ENR no significant relation was found. In addition, for SMP, 66% of the variance of K_F was explained by SOC, and for ENR 45% of the variability of K_F was explained by nitrogen content. Desorption rates were higher for SMP (reaching up to 24%) than for ENR (which reached up to 7%). Desorption percentages showed a potential relation with the adsorption parameter K_d for both SMP and ENR. These results could be useful to elucidate the evolution and dynamics of these emerging pollutants in soils and other environmental compartments, which could be of aid in controlling public health risks associated to them.
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25749. 题目: Synergistic oxidation - filtration process analysis of catalytic CuFe₂O₄ - Tailored ceramic membrane filtration via peroxymonosulfate activation for humic acid treatment
文章编号: N19121801
期刊: Water Research
作者: Yumeng Zhao, Dongwei Lu, Chengbiao Xu, Jinying Zhong, Mansheng Chen, Shu Xu, Ying Cao, Qi Zhao, Mo Yang, Jun Ma
更新时间: 2019-12-18
摘要: This work synthesized catalytic CuFe₂O₄ tailored ceramic membrane (CuFeCM), and systematically investigated the intercorrelated oxidation - filtration mechanism of peroxymonosulfate (PMS)/CuFeCM catalytic filtration for treating humic acid (HA). PMS/CuFeCM filtration exhibited enhanced HA removal efficiency while reduced the irreversible fouling resistance as compared with the conventional CM filtration. Results from HA characterizations showed that PMS/CuFeCM catalytic filtration oxidized HA into conjugated structures of smaller molecular weight. The unsaturated bonds further caused the re-agglomeration of HA, hence enhancing the size exclusion of CuFeCM. Meanwhile, oxidized HA particles with changing physicochemical properties reduced the total attractive interaction energy between CuFeCM and HA, mainly attributed to the reduced acid-base interaction energy according to the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) analysis. The changing of HA properties and HA-CuFeCM physicochemical interactions rendered more re-agglomerated HA particles retained above membrane with less attachment, which induced decreasing irreversible fouling resistance and facilitated easier external fouling removal by hydraulic cleaning. Overall, the PMS/CuFeCM configuration demonstrated in this study could provide a new insight into the synergistic oxidation - filtration interaction mechanism of hybrid catalytic ceramic membrane filtration process.
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25750. 题目: Improvement of the sludge flocculation dewatering efficient by electromagnetic wave loading: research based on removal of bound water
文章编号: N19121703
期刊: Environmental Science and Pollution Research
作者: Wenjiao Sang, Xiaoyang Li, Yijie Feng, Qian Zhang, Dong Li
更新时间: 2019-12-17
摘要: Excess sludge was loaded by 2450 MHz electromagnetic wave in this study. The mechanism of electromagnetic wave loading on the releasing of bound water before sludge flocculation dewatering was investigated through observing the changes of extracellular polymeric substances (EPS) composition, surface charge, and particle size distribution. The results showed that the 8.55 g/g total suspended solids (TSS) of bound water was reduced with 160 J/mL electromagnetic wave, and the moisture content of sludge decreased by 3.02%. The EPS structure in the sludge floc matrix was destroyed and the LB-EPS content reduced. Simultaneously, infrared spectrum analysis indicated that bound water content was correlated both to the changes of hydrophilic and hydrophobic functional groups. Moreover, protein secondary structure analysis found that looser protein structure facilitated the exposure of internal hydrophobic groups and further promoted the sludge hydrophobic properties. Additionally, electromagnetic wave disintegrated colloidal stability through dipole motion. The zeta potential increased from − 25.57 to − 14.32 mV; the medium particle size (d_0.5) decreased from 119.99 to 80.41 μm. More small molecules created in the supernatant were helpful to release bound water, which could further improve flocculation dewaterability of sludge with electromagnetic wave loading.

25751. 题目: Chemical composition of inorganic and organic species in snow/ice in the glaciers of western China
文章编号: N19121702
期刊: Science of The Total Environment
作者: Poonam Thapa, Jianzhong Xu, Bigyan Neupane, Dipesh Rupakheti
更新时间: 2019-12-17
摘要: Recent studies have revealed the abundance of dissolved organic matter (DOM) in snow/glaciers of the Tibetan Plateau (TP). Here, we present a comprehensive study on the chemical compositions of snowpit samples collected from widely distributed eight glaciers in the western China (six from the TP) to investigate the spatial variation of deposited atmospheric aerosols. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to chemically characterize the DOM in snow samples which can offer chemical properties of DOM. Highest mass concentration of dissolved species mass was observed in Tienshan Baishui No 1 glacier (TS, 6.55 ± 0.85 mg/L) close to Takalamagan Desert, whereas lowest (0.89 ± 0.18 mg/L) was observed in Zadang Glacier (ZD) in the central TP. DOM (8–40%) and calcium as well as magnesium (9–67%) were generally the most abundant chemical species. Average DOM concentration in the TP glaciers among the investigated sites were comparable. DOM was found highly oxidized with an oxygen to carbon ratio (O/C ratio) ranging from 0.82 to 1.03. Highly oxidized DOM could have related with aerosol aqueous processes as illustrated by observed organic acids. This study provides insights into the spatial variations of the DOM and dissolved inorganic matter, as well as oxidized organic aerosol, were most likely due to local and regional contribution.
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25752. 题目: Ash pretreatment of pine and biosolids produces biochars with enhanced capacity for organic micropollutant removal from surface water, wastewater, and stormwater
文章编号: N19121701
期刊: Environmental Science: Water Research & Technology
作者: Matthew James Bentley, R. Scott Summers
更新时间: 2019-12-17
摘要: An ash pretreatment process was developed and evaluated for improving sorption of 2,4-dichlorophenoxyacetic acid (2,4-D) and sulfamethoxazole (SMX) for pine and biosolids based biochars. Pine and biosolids pellets were soaked in a dissolved ash solution and pyrolized at 800 °C. The sorption performance of untreated pine biochar, pine ash pretreated biochar, untreated biosolids biochar, biosolids ash pretreated biochar, base pretreated pine biochar, and commercial powdered activated carbon (PAC) was compared in deionized water, lake water, wastewater, and stormwater for 2,4-D and SMX removal. Dose response curves were developed at 3-hour and 7-day contact times in continuously mixed batch tests. Ash pretreatment of pine yielded over an order of magnitude increase in 2,4-D and SMX sorption compared to untreated pine biochar, making it competitive with PAC. Base pretreatment was the dominant improvement process of ash pretreatment, and the improvement from ash pretreatment was linked to the precursor feedstock inherent ash content. Adsorbent performance was strongly correlated with non-micropore (>2 nm) surface area. Background organic matter character significantly impacted sorbent performance. Ash pretreatment of biochar increased organic micropollutant sorption and is applicable in low-cost water treatment scenarios, such as stormwater and wastewater treatment, as well as in low- and middle-income countries.

25753. 题目: Bioreactor performance using biochar and its effect on aerobic granulation
文章编号: N19121621
期刊: Bioresource Technology
作者: Jie Ming, Qinghong Wang, Brandon A. Yoza, Jiahao Liang, Hongqiao Guo, Jin Li, Shaohui Guo, Chunmao Chen
更新时间: 2019-12-16
摘要: The effects that rice husk (biochar-rh), rice bran (biochar-rb) and walnut shell (biochar-ws) biochar had on aerobic granulation and reactor performance during the treatment of petroleum wastewater have been investigated. The different biochars reduced aerobic granulation time by 15 days compared with the control and also increased resistance to shock loading. The average COD and TN removal increased by 3.2%-5.1% and 10%-13%, respectively. Bacteria having functional metabolisms associated with the treatment of petroleum wastewaters were enriched in granular sludge that contained biochars. The reactor containing biochar-rb was the most stable and removed the most nutrients. The reactor containing biochar-rh had the largest initial granule size. This study provides insights into how the physicochemical properties of different biochars influence aerobic granular sludge systems.

25754. 题目: Permafrost soil complexity evaluated by laboratory imaging Vis–NIR spectroscopy
文章编号: N19121620
期刊: European Journal of Soil Science
作者: W. Mueller Carsten, Steffens Markus, Buddenbaum Henning
更新时间: 2019-12-16
摘要: The biogeochemical functioning of soils (e.g. soil carbon stabilization, nutrient cycling) is determined at the interfaces of specific soil structures (e.g. aggregates, particulate organic matter (POM), organo‐mineral associations). With a growing accessibility of spectromicroscopic techniques there is an increase in nano‐ to microscale analyses of biogeochemical interfaces at the process scale, reaching from the distribution of elements and isotopes to the localization of microorganisms. A widely used approach to study intact soil structures is the fixation and embedding of intact soil samples in resin and the subsequent analyses of soil cross sections using spectromicroscopic techniques. However, it is still challenging to link such microscale approaches to larger scales at which normally bulk soil analyses are conducted. Here we report on the use of laboratory imaging Vis–NIR spectroscopy on resin embedded soil sections and a procedure for supervised image classification to determine the microscale soil structure arrangement including the quantification of soil organic matter fractions. This approach will help to upscale from microscale spectromicroscopic techniques to the cm and possibly pedon scale. Thus, we demonstrate a new approach to integrate microscale soil analyses into pedon scale conceptual and experimental approaches.

25755. 题目: Passivating Effect of Dewatered Sludge and Biochar on As-Contaminated Soil
文章编号: N19121619
期刊: Water, Air, & Soil Pollution
作者: Ninglin Luo, Jiajun Wen, Zhongwu Li, Mei Huang, Ren Yang
更新时间: 2019-12-16
摘要: The pollution caused by As in soil menaces the health of humans. There are characteristics of waste utilization, low cost, and a wide range of materials by using dewatered sludge as the main component of soil repair agents. In this paper, dewatered sludge and biochar were used as repair agents for As pollution, which were rarely reported, and the related passivation experiments were carried out. Through the analysis of experimental data of the basic physical and chemical properties of contaminated soil, various characteristics of repair agent and As morphology were obtained, and the applicability and passivation effect of dewatered sludge-biochar compound repair agent and dewatered sludge as an individual repair agent on passivation of As pollution in soil was discussed. By comparing different passivation effects, the repairing effect increases with time, and the optimal repair time was 40 days; in the set experiment group, the best passivation effect of the individual repair agent was the S3 (dry sludge accounting for 20% of soil samples) experimental group, and the best effect of the compound repair agent was the S + B3 (dry sludge and biochar accounting for 10% and 2% of soil samples, respectively) group. As a repair agent, the dewatered sludge-biochar compound repair agent can be used to repair As-contaminated soil, which provides a new method for the recycling and waste utilization of dewatered sludge.

25756. 题目: Partial substitution of chemical fertilizers with organic amendments increased rice yield by changing phosphorus fractions and improving phosphatase activities in fluvo-aquic soil
文章编号: N19121618
期刊: Journal of Soils and Sediments
作者: Muhammad Qaswar, Rushan Chai, Waqas Ahmed, Huang Jing, Tianfu Han, Kailou Liu, Xinxin Ye, Yongmei Xu, Christian Kofi Anthonio, Huimin Zhang
更新时间: 2019-12-16
摘要: Purpose: The aim of this study was to investigate the effect of combined use of chemical fertilizers with wheat straw and swine manure on rice yield and phosphorus (P) fractions distribution. Materials and methods: We selected two field experiments, both located in Hefei, Anhui province of China. We named these experimental sites as HF-1 and HF-2. The experiments HF-1 and HF-2 were initiated on 2013 and 2015 respectively in fluvo-aquic soil. Treatments included CK (no fertilizer), NPK (chemical fertilizers), NPKS (chemical fertilizers plus wheat straw), and NPKM (chemical fertilizers plus swine manure at HF-1, and chemical fertilizers plus fermented wheat straw at HF-2). Results and discussion: Results showed that NPKS and NPKM treatments increased grain yield, P use efficiency (PUE), P recovery efficiency, and partial factor productivity, and decreased apparent P balance compared with CK and NPK at both sites. NPKS and NPKM improved pH, organic matter, and nutrient contents in surface soil (0–20 cm) and also improved pH and organic matter content in sub-surface soil (20–40 cm), compared with CK and NPK treatments. Olsen P content in both soil depths was highest under NPKM, but NPKS had lower Olsen P content in sub-surface soil compared with that of NPK. Organic amendments changed P fractions and increased labile P and moderately labile P fractions, and decreased residual P compared with NPK. Organic amendments with chemical fertilizers also improved acid phosphomonoesterase and phosphodiesterase activities compared with chemical fertilization. In addition, path analysis showed relationship between soil properties and P mobility, and also explained soil properties influencing grain yield by changing PUE. Conclusions: Our results suggested that organic amendments improve crop yield through improving PUE by changing soil P fractions and increasing the phosphatase activities.

25757. 题目: Enhanced adsorption performance and regeneration of magnetic Fe 3 O 4 nanoparticles assisted extracellular polymeric substances in sulfonamide-contaminated water
文章编号: N19121617
期刊: Environmental Science and Pollution Research
作者: Shanshan Pi, Ang Li, Di Cui, Zhou Su, Lu Zhou, Fang Ma
更新时间: 2019-12-16
摘要: It is still unclear about the superiority of the nanoscale Fe₃O₄-assisted extracellular polymeric substances (EPS) compared to traditional EPS and its application feasibility in sulfonamide-contaminated aqueous system. This study reported eco-friendly and reusable EPS/Fe₃O₄ was applied in the sulfonamide-contaminated water treatment, including sulfamethoxazole (SMX), sulfamerazine (SM1), sulfamethazine (SM2) and sulfadiazine (SDZ), respectively. EPS/Fe₃O₄ exhibited the adsorption performance of 77.93%, 74.13%, 65.62%, and 56.64% for SMX, SM1, SM2 and SDZ, respectively, increased by 7.93%, 19.02%, 13.78% and 9.93% compared to traditional EPS. The initial pH value tuned adsorption performance via varying existing species of each sulfonamides. The adsorption process could be well fitted by Freundlich and pseudo-second-order kinetics models. Moreover, the multiple evidences from SEM, FTIR, zeta potential and XRD explained the adsorption mechanisms (i.e., chemisorption, ion exchange, hydroxyl group and hydrophobicity). Desorption and recycle adsorption experiments demonstrated the well regeneration ability of EPS/Fe₃O₄ as biosorbent (67.12% adsorption performance for SMX after five adsorption–desorption cycles), suggesting EPS/Fe₃O₄ was considered as a superior choice for sulfonamide-contaminated water treatment compared to the unrecyclable EPS.

25758. 题目: Comparison of CU(II), MN(II) and ZN(II) adsorption on biochar using diagnostic and simulation models
文章编号: N19121616
期刊: Chemosphere
作者: Edita Baltrėnaitė-Gedienė, Teresė Leonavičienė, Pranas Baltrėnas
更新时间: 2019-12-16
摘要: With the increase of urbanization and human consumption, the extraction of potentially toxic elements (PTEs) causes higher risk of them to enter sources of human food and potable water. Adsorption has been studied extensively as phenomena to reduce element mobility in both natural and engineered systems. The need to adapt the adsorption models to simulate the adsorption increases as the variety of adsorbents of natural origin is getting bigger and bigger due to their sustainability, availability and low costs. Adsorption of PTEs was analysed in the case of biochar which is a widely studied adsorbent, however, the studies are often limited to standard adsorption equilibrium and kinetic procedures without further analyses into the adsorbate and adsorbent contact zone. Zn(II), Cu(II) and Mn(II) were chosen study due to their nutritional and toxicological features. Diagnostic methods were used to differentiate the metal behaviour during adsorption and dynamic intraparticle model was further employed to simulate the kinetic conditions. Harkins-Jura isotherm model and pseudo-second kinetic model were determined to fit the adsorption of PTEs on biochar. According to the adsorption efficiency and capacity, PTEs fell into the following sequence: Cu(II) > Mn(II)>Zn(II). It was observed that the kinetics of Cu(II) decreased in the solution by about 1.7 times more than of Zn(II) and about 2.3 times more than of Mn(II). Cu(II) decreased faster and more suddenly than Mn(II) and Zn(II) in the solution on the particle surface and in the solution inside the particle.
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25759. 题目: The stability and fate of Soil Organic Carbon during the transport phase of soil erosion
文章编号: N19121615
期刊: Earth-Science Reviews
作者: Evy A. de Nijs, Erik L.H. Cammeraat
更新时间: 2019-12-16
摘要: Soil organic carbon (SOC) is the largest pool of non-sedimentary terrestrial carbon (C) and small changes in vertical SOC fluxes in the erosion-transport-deposition system could have a significant effect on atmospheric C levels. The ongoing sink/source discussion related to SOC seems to depend on which mechanisms are dominant during each of the three stages of soil erosion: detachment, transportation and deposition. Understanding C dynamics during each phase of soil erosion is essential to accurately assess the net effect of erosion. Currently, there is a knowledge gap when it comes to the movement of mobilized SOC from the site of detachment to the depositional site. This review provides an overview on the current understanding of the fate of eroded SOC during the transport phase of soil erosion. The stability of SOC appears to be a logistic interplay between SOC accessibility, presence of decomposers and suitable abiotic conditions. The main protection mechanisms of SOC are physical and/or chemical protection, which both make SOC inaccessible to decomposers and hence prevent mineralization. Transport subjects the SOC to disturbances and changing environmental conditions which interfere with the effectiveness of the protection mechanisms. The vulnerability of these mechanisms to erosive transport are not yet known. Increased physical impact is associated with disaggregation which releases previously protected SOC. Changes in geochemical composition of soil potentially changes the extent of organo-mineral bindings and hence either strengthen or weaken chemical protection. Complex chemical structures might result in more resistant C called biochemical stable SOC and is vulnerable to destabilization during transport due to changes in (a)biotic conditions along the trajectory. A complete understanding of the fate of mobilized SOC during transportation is essential to assess the net effect of soil erosion under different conditions. Standardization of both methodology and terminology in the field of soil erosion will further contribute to resolving the controversy on the net effect of erosion. The focus for future research should be on documenting the different interacting processes active during erosive transport and their effect on SOC fluxes.

25760. 题目: Benthic trophic structure of a Patagonian fjord (47°S): The role of hydrographic conditions in the food supply in a glaciofluvial system
文章编号: N19121614
期刊: Estuarine, Coastal and Shelf Science
作者: Ilia Cari, Claudia Andrade, Eduardo Quiroga, Erika Mutschke
更新时间: 2019-12-16
摘要: Food web studies have provided insight into the dynamics of benthic ecosystems and their stability, stimulating research into the importance of different organic matters (OM) inputs in the ecological and metabolic processes that affect community structure. Using stable isotope analysis (SIA) and Bayesian ellipses, this study examines the influence of terrestrial OM and hydrographic conditions on food web structure and niche width in a glacial system (Baker/Martínez fjord complex). Two ecological groups were identified; one located in the inner and middle fjord and the other one in the outer fjord. Both had isotopically less diverse feeding groups in comparison to non-glacier benthic communities, comprising four trophic levels. In addition, the study area exhibited high trophic redundancy (e.g., species with overlapping trophic niches) associated with chronic natural physical disturbances from glacial sedimentations, which have shaped this non-selective feeding benthic community. The trophic structure metrics suggest that the benthic food web is supported principally by primary production and terrestrial OM pathways, but macroalgal subsidies could be important to detritivores via floating kelp in the inner area of the fjord. The results of this study suggest that glaciofluvial benthic communities have higher trophic redundancy associated with environmental disturbance conducted by sediment load, shaping a benthic community with a lower alpha diversity and fewer trophic levels in comparison to no-glacier environments.