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17461. 题目: A meta-analysis of global cropland soil carbon changes due to cover cropping
文章编号: N20012901
期刊: Soil Biology and Biochemistry
作者: Jinshi Jian, Xuan Du, Mark S. Reiter, Ryan D. Stewart
更新时间: 2020-01-29
摘要: Including cover crops within agricultural rotations may increase soil organic carbon (SOC). However, contradictory findings generated by on-site experiments make it necessary to perform a comprehensive assessment of interactions between cover crops, environmental and management factors, and changes in SOC. In this study, we collected data from studies that compared agricultural production with and without cover crops, and then analyzed those data using meta-analysis and regression. Our results showed that including cover crops into rotations significantly increased SOC, with an overall mean change of 15.5% (95% confidence interval of 13.8%–17.3%). Whereas medium-textured soils had highest SOC stocks (overall means of 39 Mg ha−1 with and 37 Mg ha−1 without cover crops), fine-textured soils showed the greatest increase in SOC after the inclusion of cover crops (mean change of 39.5%). Coarse-textured (11.4%) and medium-textured soils (10.3%) had comparatively smaller changes in SOC, while soils in temperate climates had greater changes (18.7%) than those in tropical climates (7.2%). Cover crop mixtures resulted in greater increases in SOC compared to mono-species cover crops, and using legumes caused greater SOC increases than grass species. Cover crop biomass positively affected SOC changes while carbon:nitrogen ratio of cover crop biomass was negatively correlated with SOC changes. Cover cropping was associated with significant SOC increases in shallow soils (≤30 cm), but not in subsurface soils (>30 cm). The regression analysis revealed that SOC changes from cover cropping correlated with improvements in soil quality, specifically decreased runoff and erosion and increased mineralizable carbon, mineralizable nitrogen, and soil nitrogen. Soil carbon change was also affected by annual temperature, number of years after start of cover crop usage, latitude, and initial SOC concentrations. Finally, the mean rate of carbon sequestration from cover cropping across all studies was 0.56 Mg ha−1 yr−1. If 15% of current global cropland were to adopt cover crops, this value would translate to 0.16 ± 0.06 Pg of carbon sequestered per year, which is ∼1–2% of current fossil fuels emissions. Altogether, these results indicated that the inclusion of cover crops into agricultural rotations can enhance soil carbon concentrations, improve many soil quality parameters, and serve as a potential sink for atmosphere CO2.

17462. 题目: Earthquake slip surfaces identified by biomarker thermal maturity within the 2011 Tohoku-Oki earthquake fault zone
文章编号: N20012811
期刊: Nature Communications
作者: Hannah S Rabinowitz, Heather M Savage, Pratigya J Polissar, Christie D Rowe, James D Kirkpatrick
更新时间: 2020-01-28
摘要: Extreme slip at shallow depths on subduction zone faults is a primary contributor to tsunami generation by earthquakes. Improving earthquake and tsunami risk assessment requires understanding the material and structural conditions that favor earthquake propagation to the trench. We use new biomarker thermal maturity indicators to identify seismic faults in drill core recovered from the Japan Trench subduction zone, which hosted 50 m of shallow slip during the Mw9.1 2011 Tohoku-Oki earthquake. Our results show that multiple faults have hosted earthquakes with displacement ≥ 10 m, and each could have hosted many great earthquakes, illustrating an extensive history of great earthquake seismicity that caused large shallow slip. We find that lithologic contrasts in frictional properties do not necessarily determine the likelihood of large shallow slip or seismic hazard.

17463. 题目: CONTRASTING PATTERNS OF LABILE AND SEMI‐LABILE DISSOLVED ORGANIC CARBON FROM CONTINENTAL WATERS TO THE OPEN OCEAN
文章编号: N20012810
期刊: Journal of Geophysical Research: Biogeosciences
作者: R. LaBrie, J.‐F. Lapierre, R. Maranger
更新时间: 2020-01-28
摘要: Marine and freshwater prokaryotes feed primarily on bioavailable labile dissolved organic carbon (BDOCL), as well as the bioavailable fraction of the semi‐labile DOC (BDOCSL) pool. These fractions are operationally defined here as the DOC consumed within a month and greater than a month to a year and a half, respectively. Organic matter from these different pools comes from various autochthonous and allochthonous sources, but their relative bioavailability is unknown across aquatic ecosystems. To fill this gap, we compiled literature information that included 655 batch culture DOC biodegradation experiments across eight aquatic ecosystem types over the past 20 years. We show that the proportion of BDOCL across all aquatic ecosystems was surprisingly consistent (6.1%) despite a two orders of magnitude variation in initial DOC concentrations, suggesting an overall tight balance between carbon supply and consumption. A higher proportion of BDOCL, 16.3% on average, was observed in high productivity ecosystems. BDOCSL, on the other hand, gradually decreased from 16.0% in lakes to 7.2% in estuaries to undetectable in the open ocean, suggesting that terrestrial connectivity regulates BDOCSL across the continuum. Our results support that recent primary production fuels short‐term prokaryotic DOC needs with an increasing reliance on the abundant BDOCSL pool as ecosystems approach the land–water interface. Batch culture experiments show that BDOCSL is metabolizable in freshwater and coastal environments, but not in the open ocean. We estimate that BDOCSL can sustain 62% of total prokaryotic biomass in inland waters and coasts, and an estimated total of 16.7% across aquatic biomes.

17464. 题目: Efficient Removal of Cr(VI) from Aqueous Solution by Fe-Mn Oxide-Modified Biochar
文章编号: N20012809
期刊: Water, Air, & Soil Pollution
作者: Yiyang Zhu, Wencan Dai, Kai Deng, Ting Pan, Zhijie Guan
更新时间: 2020-01-28
摘要: Removal of Cr(VI) is of great concern due to its high mobility and toxicity in the natural environment. In this study, Fe-Mn oxide-modified biochar composite (FMBC) was prepared by impregnation to remove Cr(VI) from aqueous systems. The effect of Fe/Mn ratio, adsorbent dosage, solution pH, initial Cr(VI) concentration, and temperature were investigated on the Cr(VI) removal efficiency. Results showed that F1M3BC (with an Fe/Mn ratio of 1:3) had the maximum Cr(VI) adsorption capacity of 118.03 mg g−1 at pH 2.0. The removal efficiency of Cr(VI) by F1M3BC (91.79%) was higher than that by the pristine BC (32.17%). Experimental data fitted well with the Langmuir model and the pseudo-second-order kinetics equation. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous. Multiple techniques including BET, SEM, FTIR, and XPS were used to analyze the possible adsorption mechanisms. It was found that the increased adsorption of Cr(VI) on F1M3BC, mainly occurred due to electrostatic attraction and Cr(VI) reduction, together with Cr(III) complexation. Furthermore, regeneration studies indicated that F1M3BC could be recycled for up to six cycles without loss of activity. Therefore, F1M3BC may be promising for environmental applications removing Cr(VI) from aqueous systems.

17465. 题目: Analysis of urban land cover influence to organic carbon and nutrients in surface water via impacted groundwater
文章编号: N20012808
期刊: Environmental Monitoring and Assessment
作者: Katarzyna Puczko, Elżbieta Jekatierynczuk-Rudczyk
更新时间: 2020-01-28
摘要: This paper presents an object-oriented approach for analysing and characterising the urban landscape structure and its influence on the quality of surface waters and shallow groundwater. We investigated springs, streams and ponds from an urban area. The land cover classification was adopted with the conceptual framework of urban land cover (HERCULES model). This study has demonstrated that water quality in the urban area is strongly related to land cover, and the degree of its transformation is not the same in all types of waters. The land with forests and shrubs does not have many extreme values in water chemical characteristics. Statistical analyses indicated that the main environmental factors influencing water chemistry are impermeable surfaces such as buildings. They are an essential element which deteriorates water quality. The patches with buildings and pavements were characterised by a wide gradient of nutrient concentration in rivers and ponds. Shallow groundwater had a limited effect on surface water quality.

17466. 题目: Emerging investigator series: Control of membrane fouling by dissolved algal organic matter using pre-oxidation with coagulation as seawater pretreatment
文章编号: N20012807
期刊: Environmental Science: Water Research & Technology
作者: Bhaskar Deka, Jiaxin Guo, Sanghyun Jeong, Manish Kumar, Alicia Kyoungjin An
更新时间: 2020-01-28
摘要: Marine algae produce organic matter, namely algal organic matter (AOM), especially during a harmful algal bloom. AOM has been recognised as a key cause for the formation of organic fouling on membranes in seawater desalination applcations. In this study, pre-oxidation of AOM by potassium permanganate (KMnO4) and sodium hypochlorite (NaOCl) was investigated. In addition, ferric (Fe3+) and alum (Al3+) coagulants were used for subseqent coagulation. Two different operational modes, conventional coagulation-flocculation-sedimentation (CFS) and coagulation-flocculation-dissolved air flotation (CF-DAF) processes, were used to evaluate pretreatment performance using synthetic AOM with an initial dissolved organic carbon (DOC) of around 4.8 mg C L-1 (turbidity ≈ 4.47 NTU, pH ≈ 8). Pre-oxidation with coagulation removed more AOM, compared to oxidation or coagulation alone. The removal of DOC by NaOCl-Fe3+ is relatively high when compared to other combinations of oxidant and coagulant because of in-situ ferrate (Fe6+) generation, which was detected by the ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid))-ultraviolet visible (UV-Vis) method. Pre-oxidation with 1.5 mg L-1 NaOCl followed by coagulation with 2.5-3.0 mg L-1 Fe3+ achieved a maximum DOC removal of 65-76% during the CFS treatment; while, the DOC removal could further increased up to 83-85% by introducing CF-DAF . Particularly, the NaOCl-Fe3+ treatment generated 1.31 mg L-1 of in-situ ferrate (Fe6+). Finally, pre-oxidation and coagulation coupled with DAF sucessfully reduced fouling and lowered flux decline in a microfiltration (MF) membrane. Non-invasive optical coherence tomography (OCT) was performed to monitor the fouling development on the MF membrane before and after pretreatment.

17467. 题目: New insights into filamentous sludge bulking: The potential role of extracellular polymeric substances in sludge bulking in the activated sludge process
文章编号: N20012806
期刊: Chemosphere
作者: Wei-Ming Li, Xi-Wen Liao, Jin-Song Guo, Yu-Xin Zhang, You-Peng Chen, Fang Fang, Peng Yan
更新时间: 2020-01-28
摘要: The control of filamentous sludge bulking has been regarded as an important issue in the activated sludge process due to there is still a lack of understanding of the bulking mechanisms. In this study, changes in the extracellular polymeric substances (EPS) and metabolic profile of bulking sludge based on the proteomics level was investigated to reveal the potential role of EPS in deteriorating sludge floc stability and structure during filamentous bulking. The results showed that the EPS content gradually decreased from 210.23 mg/g volatile suspended solids (VSS) to 131.34 mg/g VSS during sludge bulking. The protein (PN) content of the EPS significantly decreased from 173.33 mg/g VSS to 95.42 mg/g VSS during sludge bulking. However, a gradual increase in polysaccharides (PS) was observed. Bacterial aggregation was hindered by the changes in the EPS and its components. The excessive proliferation of filamentous bacteria had a significant effect on the molecular functions of the extracellular PN and metabolic pathways of the EPS. The proteins associated with the hydrophobic amino acid synthesis decreased, whereas the proteins associated with the hydrophilic amino acid synthesis increased during sludge bulking. Electric repulsion was the key factor affecting the aggregation and flocculation ability of the bacteria during sludge bulking. The changes in the EPS and its components induced by the excessive proliferation of filamentous bacteria resulted in a loose floc structure and poor settling performance during sludge bulking. These findings provide new insights into sludge bulking during the activated sludge process.
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17468. 题目: Molten salt induced nitrogen-doped biochar nanosheets as highly efficient peroxymonosulfate catalyst for organic pollutant degradation
文章编号: N20012805
期刊: Environmental Pollution
作者: Yi Xie, Wanrong Hu, Xuqian Wang, Wenhua Tong, Panyu Li, Hui Zhou, Yabo Wang, Yongkui Zhang
更新时间: 2020-01-28
摘要: Advanced oxidation processes based on carbon catalysis is a promising strategy possessing great potential for environmental pollution degradation. Herein, nitrogen-doped biochar nanosheets (NCS-x) were synthesized using a nitrogen-rich biomass (Candida utilis) as sole precursor. The involvement of environmental-friendly molten salt (NaCl and KCl) in pyrolysis process not only facilitated the exfoliation of biochar, but also favored the retention of N element in biochar. When applying as catalyst for peroxymonosulfate activation, the as-obtained NCS-6 exhibited outstanding performance in catalytic degradation of bisphenol A (BPA). A 100% removal efficiency was observed in 6 min with fast reaction kinetic (k = 1.36 min−1). Based on quenching test and in-situ electron paramagnetic resonance analysis, both radical pathway and non-radical pathway were suggested to be involved in BPA degradation, while singlet oxygen was identified as the dominant reactive oxygen species. Furthermore, the ecotoxicity evaluation using Chlorella vulgaris as ecological indicator indicated that BPA solution after degradation was less toxic than the original solution. It is expected that this green and facile strategy holds great promise for value-added conversion of nitrogen-rich biomass to highly efficient biochar nanosheets for environment remediation.
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17469. 题目: NOM mitigates the phytotoxicity of AgNPs by regulating rice physiology, root cell wall components and root morphology
文章编号: N20012804
期刊: Environmental Pollution
作者: Xitong Huang, Yong Li, Ke Chen, Haiyan Chen, Fei Wang, Xiaomin Han, Beihai Zhou, Huilun Chen, Rongfang Yuan
更新时间: 2020-01-28
摘要: Natural organic matter (NOM) affects the environmental behaviors of AgNPs, which may change their phytotoxicity to plants. However, more evidence can be provided to illustrate how NOM influences AgNPs-induced phytotoxicity. In this study, using rice (Oryza sativa) as a model, the effects of NOM, Suwannee River humic acid (SRHA) and fulvic acid (FA), on the dissolution and phytotoxicity of AgNPs were investigated. Silver ions decreased in both AgNPs and AgNO3 solution in the presence of NOM, and the effect of SRHA was stronger than FA. Image-XRF (iXRF) results showed that Ag mainly remained in the root rather than the shoot of rice seedling exposed to AgNPs. NOM mitigated the negative effects of AgNPs and AgNO3 on rice with lower germination inhibition rate, less chlorophyll reduction, more relative biomass and less O2•− content. Moreover, NOM improved root cell viability according to FDA fluorescent dye as well as maintained the normal root morphology. Interestingly, the neutral sugars content from pectin, hemicellulose 1, hemicellulose 2 and cellulose of root cell wall in AgNPs and AgNO3 treatments differed from the control, while it was close to the regular content in AgNPs/AgNO3+SRHA/FA groups, which implied that NOM regulated the changes. Besides, SRHA led to less germination and less relative biomass than FA due to different chemical characters. Thus, NOM needs to be considered when studying the phytotoxicity of AgNPs.
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17470. 题目: No Evidence for Brown Carbon Formation in Ambient Particles Undergoing Atmospherically Relevant Drying
文章编号: N20012803
期刊: Environmental Science: Processes Impacts
作者: Vikram Pratap, Michael Battaglia Jr., Annmarie G Carlton, Christopher J Hennigan
更新时间: 2020-01-28
摘要: Recent laboratory studies have reported the formation of light-absorbing organic carbon compounds (brown carbon, BrC) in particles undergoing drying. Atmospheric particles undergo cycles of humidification and drying during vertical transport and through daily variations in temperature and humidity, which implies particle drying could potentially be an important source of BrC globally. In this work, we investigated BrC formation in ambient particles undergoing drying at a site in the eastern United States during summer. Aerosol BrC concentrations were linked to secondary organic aerosol (SOA) formation, consistent with seasonal expectations for this region. Measurements of water-soluble organic aerosol concentrations and light absorption (365 nm) were alternated between an unperturbed channel and a channel that dried particles to 41% or 35% relative humidity (RH), depending on the system configuration. The RH maintained in the dry channels was below most ambient RH levels observed throughout the study. We did not observe BrC formation in particles that were dried to either RH level. The results were consistent across two summers, spanning ~5 weeks of measurements that included a wide range of RH conditions and organic and inorganic aerosol loadings. This work suggests that mechanisms aside from humidification-drying cycles are more important contributors to ambient particle BrC loadings. The implications of this work on the atmospheric budget of BrC are discussed.

17471. 题目: Effect of soil organic matter (SOM) on the degradation of polycyclic aromatic hydrocarbons using Pleurotus dryinus IBB 903-A microcosm study
文章编号: N20012802
期刊: Journal of Environmental Management
作者: Abiram Karanam Rathankumar, Kongkona Saikia, Krishnakumar Ramachandran, Ramon Alberto Batista, Hubert Cabana, Vinoth Kumar Vaidyanathan
更新时间: 2020-01-28
摘要: Bioremediation of polycyclic aromatic hydrocarbons (PAHs) in soil matrix is often arbitrated by the presence of soil organic matter (SOM). The present study focuses on determining the effect of the soil organic content on the mycoremediation of two model PAHs, phenanthrene (Phe) and benzo(a) pyrene (BaP) through microcosm studies. On comparing various microcosm strategies, a maximum degradation of Phe (99%) and BaP (48.5%) in soil bioaugmented with Pleurotus dryinus IBB 903, followed by, biostimulation with the degradation of Phe (89.9%) and BaP (24.8%) were noted. On relating the degradation pattern with lignolytic enzyme cocktail production, a laccase activity of 108 U/Kg at day 21, aryl alcohol oxidase (411 U/Kg) and manganese peroxidase (52.2 U/Kg) at day 14 along with lignin peroxidase (481 U/Kg) at day 21 were noted in fungal augmented soils, which were comparatively higher than levels observed in the bio-stimulation. Investigating the impact of different concentration of SOM (3–12%), a maximum remediation of Phe by 100% at 9% SOM in days 28 and 58.19% for BaP at 12% SOM, respectively was exhibited. Further, the biosorption effect of PAHs in abiotic condition showed a positive correlation with the increase in SOM, with a maximum adsorption of 3.78% Phe, and 6.93% BaP. The results support that the nominal adsorption ability of SOM, and helps in enhancing the microbial growth, thereby improving their degradation potentials, when less than 6% of SOM was utilized. Overall, this work establishes the critical role of organic matter in the soil with reference by simultaneous stimulation and degradation capability in complete PAHs remediation.
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17472. 题目: Simultaneous adsorption and oxidation of antimonite onto nano zero-valent iron sludge-based biochar: indispensable role of reactive oxygen species and redox-active moieties
文章编号: N20012801
期刊: Journal of Hazardous Materials
作者: Dongning Wei, Bingyu Li, Lin Luo, Yongxin Zheng, Liuhui Huang, Jiachao Zhang, Yuan Yang, Hongli Huang
更新时间: 2020-01-28
摘要: The nano zero-valent iron sludge-based biochar (nZVI-SBC) was prepared in this study to eliminate Sb(III) from aqueous solutions, which was characterized by BET, SEM, XRD, TEM, FTIR, XPS. Our results proved that the incorporated nZVI on SBC matrix could significantly enhance eliminating Sb(III), and the max-adsorption capacity (160.40 mg g−1) can be achieved at pH = 4.8 ± 0.2 and temperature of 298 K. The effect of co-existing anions and natural organic matters on the Sb(III) adsorption efficiencies were systematically investigated. The surface complexation is the possible adsorption mechanisms by FTIR and XPS. Furthermore, mechanistic investigation revealed that •OH and hydroquinone radical (H-SQ•) could be the primary oxidants for the transformation of Sb(III) under oxic conditions, while 9,10-phenanthrene quinone radical (P-SQ•) were responsible under anoxic conditions. Thus, the enhanced elimination of Sb(III) from aqueous solution was ascribed to the combined adsorption and oxidation. The potential engineering application of nZVI-SBC can be proved through three actual water matrix experiments, including lake water, river water and acid mine drainage. Our present findings proved that nZVI-SBC could be a potential adsorbent, given the excellent performance in the adsorption processes, as well as the toxicity alleviating ability and economic advantages, especially under sub-surface water.
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17473. 题目: Influence of inorganic additives on wheat straw composting: Characterization and structural composition of organic matter derived from the process
文章编号: N20012706
期刊: Journal of Environmental Management
作者: Jorge Medina, Carlos M. Monreal, Mónica Antilén, Marcela Calabi-Floody, Marta Velasco-Molina, Sebastián Meier, Fernando Borie, Pablo Cornejo, Heike Knicker
更新时间: 2020-01-27
摘要: Metallic oxides and clay minerals have gained increasing interest as additives of composting due to their influence in greenhouse gas emissions reduction and their effectivity in the stabilization of carbon both in compost and soils, leading to a cleaner compost production and potentially C sequestrant amendments. In this study, wheat straw (WS) was co-composted with iron oxide and allophanic soil and their influence on WS composting and composition of the end-products was evaluated. WS compost and their humic like-substances (HS) fraction were characterized by chemical and spectroscopic analyzes. After 126 days of process, the elemental composition showed slight differences of the N content for compost and HS, where the C/N atomic ratio tended to decrease relative to the initial material (WS; ~130). This trend was more pronounced in the HS from co-composted treatments (<30). The addition of inorganic materials increased the total acidity and phenolic-OH group contents (~15 and 14 mEq g−1 respectively, iron oxide treatment) relative to the treatment without inorganic additives. Nevertheless, the FTIR and solid-state 13CNMR spectroscopy barely support the wet chemical analysis and revealed a similar final composition between all the studied compost treatments. These results suggest that the incorporation of these materials as compost additives had no major effect on the spectroscopic features of the end-products, however, critical changes of the properties such as the extractability, functionality and composition of HS were revealed by traditional methods. In conclusion, the supply of metal oxides and clays could impact the aerobic composting of WS favorizing the stabilization of certain C pools and adsorptive properties of the end-products, that is of importance in production of amendments suitable for being used in degraded and contaminated soils. Nevertheless, under the experimental conditions of our research C stabilization apparently depends of other mechanisms that still need to be elucidate.
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17474. 题目: Ultrafast sequestration of cadmium and lead from water by manganese oxide supported on a macro-mesoporous biochar
文章编号: N20012705
期刊: Chemical Engineering Journal
作者: Shunli Wan, Lian Qiu, Gui Tang, Weiyang Chen, Yan Li, Bin Gao, Feng He
更新时间: 2020-01-27
摘要: Porous carrier supported metal oxide composites possess significant potential for sequestration of heavy metals from various waters. However, slow diffusion of targeted metal ions within the micropores of the porous carriers is a key technical barrier limiting practical application of these hybrid adsorbents, particularly in high flow systems. In this study, we first synthesized a biochar with enlarged pore channel (namely K-BC) by adding KHCO3 during the biochar pyrolysis process and then employed the K-BC as a supporter to fabricate a new manganese oxide-based composite (namely HMO-K-BC). It is striking that the effective intra-particle diffusion coefficient D of Pb(II) inside the K-BC is comparable to that in aqueous solution (1.5 × 10−6 v.s. 2.1 × 10−6 cm2 s−1). Although the D value of Pb(II) inside the HMO-K-BC was reduced to 1.8 × 10−7 cm2 s−1, it is still 1–2 orders of magnitude higher than that of conventional adsorbents such as activated carbon, ion exchanger and biochar. As a result, the HMO-K-BC can rapidly sequestrate Pb(II) and Cd(II) within 7.5 min. The HMO-K-BC can also selectively remove Pb(II) and Cd(II) in the presence of high level Ca(II) and humic acid. Column tests further showed that HMO-K-BC was able to effectively treat simulated and real Pb(II)- and Cd(II)-polluted wastewater in a high-flow system with superficial liquid velocity of 0.53 m h−1 (20 BV h−1). All the results manifest that expanding pores of biochar is a promising measure for promoting the practical application of biochar supported composites in wastewater treatment.
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17475. 题目: Organo-mineral complexes protect condensed organic matter as revealed by benzene-polycarboxylic acids
文章编号: N20012704
期刊: Environmental Pollution
作者: Zhaofeng Chang, Luping Tian, Fangfang Li, Min Wu, Christian E.W. Steinberg, Bo Pan, Baoshan Xing
更新时间: 2020-01-27
摘要: Condensed organic matters (COM) with black carbon-like structures are considered as long-term carbon sinks because of their high stability. It is difficult to distinguish COM from general organic matter by conventional chemical analysis, thus the contribution by and interaction mechanisms of organo-mineral complexes in COM stabilization are unclear and generally neglected. Molecular markers related to black carbon-like structures, such as benzene polycarboxylic acids (BPCAs), are promising tools for the qualitative and quantitative analysis of COM. In this study, one natural soil and two cultivated soils with 25 y- or 55 y-tillage activities were collected and the distribution characteristics of BPCAs were detected. All the investigated soils showed similar BPCA distribution pattern, and over 60% of BPCAs were detected in clay fraction. The extractable BPCA contents were substantially increased after mineral removal. The ratios of BPCA contents before and after mineral removal indicate the extent of COM-mineral particle interactions, and our results suggested that up to 73% COM were protected by mineral particles, and more stronger interactions were noted on clay than on silt. The initial cultivation dramatically decreased COM-clay interactions, and this interaction was recovered only slowly after 55-y cultivation. Kaolinite and muscovite are important for COM protection. But a possible negative correlation between BPCAs and reactive iron oxides of the cultivated soils suggested that iron may promote COM degradation when disturbed by tillage activities. This study provided a new angle to study the stabilization of COM and emphasized the importance of organo-mineral complexes for COM stabilization.
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17476. 题目: Nutrients release and greenhouse gas emission during decomposition of Myriophyllum aquaticum in a sediment-water system
文章编号: N20012703
期刊: Environmental Pollution
作者: Pei Luo, Xiong Tong, Feng Liu, Min Huang, Juan Xu, Runlin Xiao, Jinshui Wu
更新时间: 2020-01-27
摘要: Aquatic macrophytes play a significant role in nutrients removal in constructed wetlands, yet nutrients could be re-released due to plant debris decomposition. In this study, Myriophyllum aquaticum was used as a model plant debris and three debris biomass levels of 3 g, 9 g dry biomass, and 20 g fresh biomass (D3, D9, and F20, respectively) were used to simulate 120-d plant debris decomposition in a sediment-water system. The biomass first-order decomposition rate constants of D3, D9, and F20 treatments were 0.0058, 0.0117, and 0.0201 d−1, respectively with no significant difference of decomposition rate among three mass groups (p > 0.05). Plant debris decomposition decreased nitrate and total nitrogen concentrations but increased ammonium, organic nitrogen, and dissolved organic carbon (DOC) concentrations in overlying water. The parallel factor analysis confirms that three components of DOC in overlying water changed over decomposition time. Emission fluxes of methane and nitrous oxide in the plant debris treatments were several to thousands of times higher than the control group within the initial 0–45 d, which was mainly attributed to DOC released from the plant debris. Plant debris decomposition can affect the gas emission fluxes for relatively shorter time (30–60 d) than water quality (>120 d). The 16S rRNA, nirK, nirS and hazA gene abundance increased in the early stage for plant debris treatments, and then decreased to the end of 120-d incubation time while ammonia monooxygenase α-subunit A gene abundance of ammonia-oxidizing archaea and bacteria had no large variations during the entire decay time compared with no plant debris treatment. The results demonstrate that decomposition of M. aquaticum debris could affect greenhouse gas emission fluxes and microbial gene abundance in the sediment-water system besides overlying water quality.
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17477. 题目: Biochar is superior to lime in improving acidic soil properties and fruit quality of Satsuma mandarin
文章编号: N20012702
期刊: Science of The Total Environment
作者: Songwei Wu, Ying Zhang, Qiling Tan, Xuecheng Sun, Wenhua Wei, Chengxiao Hu
更新时间: 2020-01-27
摘要: A better understanding is required for using biochar as an alternative option to lime materials for sustainable amelioration of soil acidity and improvement of fruit quality in acidic soils. In this study, a pot experiment was conducted to investigate the comparative effects of biochar (three different dosages of biochar, 1%, 2% and 4%, were denoted by BC-1, BC-2 and BC-3, respectively) and lime (three different dosages of lime, 1.2, 2.4 and 3.6 g kg1, were denoted by L-1, L-2 and L-3, respectively) on soil properties and fruit acidity of Satsuma mandarin. The decreased rates of fruit titratable acid (TA) by BC-1, BC-2 and BC-3 were 16.18%, 25.00% and 14.71%, which were higher than those by L-1, L-2 and L-3 were 11.76%, 16.18% and 5.88%. Moreover, the increased rates of fruit total soluble solid (TSS)/TA were 14.94%, 31.73%, 28.04% by BC-1, BC-2 and BC-3, but were 11.42%, 21.77%, 10.15% by L-1, L-2 and L-3, suggesting that biochar had better effects on improving fruit quality. Acidic soil properties were improved by biochar and lime, but biochar had better amelioration effects, as evidenced by soil-treated with BC-2 and BC-3 had greater increases of soil pH, soil respiration (SR) and microbial metabolic quotient, activities of soil urease (SU), invertase (SI), catalase (CAT) and cellulose (SC), and concentrations of soil phosphorus (P), potassium (K) and magnesium (Mg). Principal component analysis showed that soil pH, SR, SU, SI and CAT were main contributors to the differences of improvement effects of biochar and lime. Correlation analysis showed that fruit TA had negative relationships with soil pH, SU, SI, CAT, SC and soil P, K, Mg. This study indicates that the better effects of biochar on improving fruit quality of Satsuma mandarin were associated with the greater effects of it on improving acidic soil properties.
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17478. 题目: Influence of laccase treatment on fouling layer formation in ultrafiltration of birch hot-water extract
文章编号: N20012701
期刊: Separation and Purification Technology
作者: Tiina Virtanen, Jussi Lahti, Anna Kalliola, Tarja Tamminen, Mika Mänttäri, Mari Kallioinen
更新时间: 2020-01-27
摘要: Fouling problems caused by lignin have been limiting the use of membranes in the recovery of value-added materials from biorefinery streams. Fortunately, laccase-based catalytic pretreatments enable modification of lignin to the less fouling form. Because the mechanisms behind the fouling caused by ligneous compounds in wood-based streams are still not deeply understood, the aim of this study was to find out how laccase oxidation affects membrane fouling caused by pressurized hot-water extract. The effect of laccase on the fouling tendency of birch extract was explored both with adsorptive and pressure-driven experiments. The results suggested that laccase treatment increased the molar mass of lignin and improved significantly filtration capacity of commercial polyethersulphone membrane, possibly due to formation of less dense foulant layer during the filtration. Based on FTIR and BET results laccase oxidation decreased both adsorptive and pressure-driven fouling caused by lignin. However, decreases in pure water permeabilities were higher for the samples that were fouled with laccase treated extract. This may have originated from the transformation in the fouling mechanism from the pore narrowing to the pore blocking and could be prevented by the selection of a membrane with a different pore size.
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17479. 题目: Remediation of organic arsenic contaminants with heterogeneous Fenton process mediated by SiO 2 -coated nano zero-valent iron
文章编号: N20012607
期刊: Environmental Science and Pollution Research
作者: Yuancai Lv, Siyi Huang, Guofu Huang, Yifan Liu, Guifang Yang, Chunxiang Lin, Gao Xiao, Yonghao Wang, Minghua Liu
更新时间: 2020-01-26
摘要: Given their considerable solubility in water and potentially high toxicity to human health, organoarsenic compounds have become an emerging contaminant. Herein, a heterogeneous Fenton process mediated by SiO2-coated nano zero-valent iron (SiO2-nZVI) was employed to simultaneously remove the p-arsanilic acid (p-ASA, a typical organoarsenic compound) and the released arsenic. The initial pH value significantly influenced on the degradation of p-ASA and at the optimal pH (3.0), p-ASA (10 mg L−1) could be completely oxidized to As(V), NH4+, and plentiful phenolic compounds such as phenol and p-hydroquinone via the cleavage of C–N and C–As bonds within 60 min in pure water. Meanwhile, although the formed lepidocrocite and magnetite on the surface of SiO2-nZVI significantly limited the reutilization, they played a vital role in the adsorption of the released As(V) and the residual arsenic levels in the effluent were as low as 0.031 mg L−1, meeting both the drinking water standard of the World Health Organization (WHO) and the surface water standard of China (0.05 mg L−1). Furthermore, high-level dissolved organic matters (DOM) (> 2 mg C L−1) exhibited strong interference with both the oxidation of p-ASA and adsorption of arsenic, but the interference could be eliminated by increasing the SiO2-nZVI dosage or adding H2O2. Importantly, this system could completely remediate p-ASA in a short time and simultaneously avoid the secondary pollution caused by inorganic arsenic, which was significant for the remediation of organoarsenic pollutants in swine wastewater.

17480. 题目: Effect of Biochar and Coal Fly Ash Soil Amendments on the Leaching Loss of Phosphorus in Subtropical Sandy Ultisols
文章编号: N20012606
期刊: Water, Air, & Soil Pollution
作者: Nadeesha L. Ukwattage, Yuncong Li, Yandong Gan, Tiantian Li, Ranjith P. Gamage
更新时间: 2020-01-26
摘要: Leaching of phosphorus fertilizer from loose-structured subtropical soils is a major course of agricultural water pollution in southeastern USA. Soil amendments play a major role in the phosphorus retention in soil through different mechanisms. In the present study we tested the effect of two soil amendments; biochar and coal fly ash in immobilizing the soluble phosphorus fertilizer added to sandy Ultisol soils from subtropical USA. Column leaching tests were conducted with Ultisol soil added with biochar (from avocado branch cut biomass) and coal fly ash at 5 tons/ha rate, under simulated rainfall, to collect the leachate over five pore volumes. The leachate was analyzed for the phosphate phosphorus content. In the end, the soil columns were carefully extracted, sectioned and analyzed for the total phosphorus, after acid digestion. Results showed 50% and 6% drop of soluble phosphorus leaching loss in biochar and coal fly ash added soil respectively. Soil amendments have shifted the loosely bound phosphorus into the Ca/Mg bound and Al/Fe/Mn bound pools which are not readily water extractable. Addition of biochar and coal fly ash together showed a synergistic interaction effect in reducing the leaching loss of phosphorus which needs further investigation to understand the exact mechanism.

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