61. 题目: Soil erosion impacts on nutrient deposition in a typical karst watershed
期刊: Agriculture, Ecosystems & Environment
作者: Chengfang Li, Zhongcheng Wang, Zhenwei Li, Xianli Xu
摘要: Soil erosion has a significant influence on nutrient redistribution and deposition. However, the effect of soil erosion on nutrient deposition remains unclear in karst areas such as southwest China, which represents an ecologically fragile zone experiencing severe soil erosion. The objective of this study was to investigate the characteristics of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) deposition in a karst watershed of southwest China over the past 60 years and evaluate the relationship between soil erosion and nutrient deposition. The peak-cluster depressions in southwest China are typical for the geomorphological type, which is an ideal place to determine the sediment chronology, and the estimation of sediment and nutrient deposition rates. The 137Cs, 210Pbex, particle size distribution, and nutrients of 194 soil samples in three sediment cores retrieved from a karst depression were investigated to evaluate the effect of soil erosion on nutrient deposition. Results showed that there was a significant negative correlation between nutrient concentrations and clay content (P < 0.001). Generally, compared with 137Cs, 210Pbex had a higher correlation with SOC and TN. In an undisturbed sediment profile, Pb/Cs can reflect nutrient dynamics better than a single nuclide. The nutrient deposition rates increased before 1953, reached its maximum in 1954–1956, and then dropped rapidly from 1957 to 2015. The sediment deposition rates were negatively correlated with nutrient concentrations (P < 0.01), but had a positive influence on nutrient deposition rates (P < 0.01). This implied that the temporal variation in nutrient deposition rates over the past 60 years was dominated by soil erosion rather than nutrient concentrations. This study provides a new insight to explore the historical nutrient deposition rates in a peak-cluster karst depression, and may help effectively control soil erosion and sustainable development of agro-ecosystems.
62. 题目: Rapid, concurrent formation of organic sulfur and iron sulfides during experimental sulfurization of sinking marine particles
期刊: Global Biogeochemical Cycles
作者: M. R. Raven, R. G. Keil, S. M. Webb
摘要: Organic matter (OM) sulfurization can enhance the preservation and sequestration of carbon in anoxic sediments, and it has been observed in sinking marine particles from marine O2-deficient zones. The magnitude of this effect on carbon burial remains unclear, however, because the transformations that occur when sinking particles encounter sulfidic conditions remain undescribed. Here, we briefly expose sinking marine particles from the eastern tropical North Pacific O2-deficient zone to environmentally relevant sulfidic conditions (20°C, 0.5 mM [poly]sulfide, two days) and then characterize the resulting solid-phase organic and inorganic products in detail. During these experiments, the abundance of organic sulfur in both hydrolyzable and hydrolysis-resistant solids roughly triples, indicating extensive OM sulfurization. Lipids also sulfurize on this timescale, albeit less extensively. In all three pools, OM sulfurization produces organic monosulfides, thiols, and disulfides. Hydrolyzable sulfurization products appear within ≤ 200-μm regions of relatively homogenous composition that are suggestive of sulfurized extracellular polymeric substances (EPS). Concurrently, reactions with particulate iron oxyhydroxides generate low and fairly uniform concentrations of iron sulfide (FeS) within these same EPS-like materials. Iron oxyhydroxides were not fully consumed during the experiment, which demonstrates that organic materials can be competitive with reactive iron for sulfide. These experiments support the hypothesis that sinking, OM- and EPS-rich particles in a sulfidic water mass can sulfurize within days, potentially contributing to enhanced sedimentary carbon sequestration. Additionally, sulfur-isotope and chemical records of organic S and iron sulfides in sediments have the potential to incorporate signals from water column processes.
63. 题目: Removal of oxytetracycline promoted by manganese-doped biochar based on density functional theory calculations: Comprehensive evaluation of the effect of transition metal doping
期刊: Science of The Total Environment
作者: Zhipeng Dai, Lu Zhao, Shuchuan Peng, Zhengbo Yue, Xinyuan Zhan, Jin Wang
摘要: The regulation of surface electrons by non-metal doping of biochar (BC) is environmentally and ecologically significant. However, systematic studies on the regulation of surface electrons by transition metal doping are lacking. The present study is based on the observation that the removal efficiency of oxytetracycline (OTC) by Mn-doped BC is eight times higher than that of undoped BC in 20 min. The effects of Mn doping on the crystal phase formation, persistent free radicals (PFRs), electron density, molecular orbitals, and nucleophilic active sites of BC are investigated, and the intermediate products of OTC are evaluated. Mn doping enhances the signal for sp2-hybridised carbon–carbon double bond, forms more delocalised π-bonds, and promotes the formation of free radicals centred on the carbon atoms. The specific surface area of BC increases, and manganese oxide is formed on the its surface. Density functional theory calculations show that Mn doping accelerates the electron transfer of BC, provides additional electrons for the BC system, and makes this system more ionised. OTC molecules preferentially attack the nucleophilic reaction sites near Mn atoms based on molecular electrostatic potential measurements. Therefore, this study provides new insights into the surface electronic structures regulated by transition metal elements.
64. 题目: Biochar-induced priming effects in soil via modifying the status of soil organic matter and microflora: A review
期刊: Science of The Total Environment
作者: Maria Rasul, Jinwoo Cho, Hyun-Sang Shin, Jin Hur
摘要: Biochar (BC) application has the potential to be integrated into a carbon-trading framework owing to its multiple environmental and economic benefits. Despite the increasing research attention over the past ten years, the mechanisms of BC-induced priming effects on soil organic carbon mineralization and their influencing factors have not been systematically considered. This review aims to document the recent progress in BC research by focusing on (1) how BC-induced priming effects change the soil environment, (2) the factors governing the mechanisms underlying BC amendment effects on soils, and (3) how BC amendments alter soil microbial communities and nutrient dynamics. Here, we carried out a detailed examination of the origins of different biochar, its pyrolysis conditions, and potential interactions with various factors that affect BC characteristics and mechanisms of C mineralization in primed soil. These findings clearly addressed the strong linkage between BC properties and abiotic factors that leads to change the soil microclimate, priming effects, and carbon stabilization. This review offers an overview of a fragmented body of evidence and the current state of understanding to support the application of BC in different soil environments with the aim of sustaining or improving the agricultural crop production.
65. 题目: Removal of triclosan from aqueous solution via adsorption by kenaf‐derived biochar: its adsorption mechanism study via spectroscopic and experimental approaches
期刊: Journal of Environmental Chemical Engineering
作者: Eun-Ji Cho, Jin-Kyu Kang, Joon-Kwan Moon, Byung-Hwan Um, Chang-Gu Lee, Sanghyun Jeong, Seong-Jik Park
摘要: Biochars derived from kenaf were synthesized to adsorb triclosan from an aqueous solution. The triclosan adsorption mechanism of the biochars pyrolyzed at various temperatures (300, 400, 600, and 750 °C) was explored using physical/chemical analyses (FE-SEM, EDS, EA, XRF, pHpzc, N2 adsorption-desorption, SAXS, ATR-FTIR, and XPS). The triclosan adsorption by the kenaf biochar increased as the pyrolysis temperature increased, except for 450 °C, which showed the lowest adsorption capacity. The kenaf biochar synthesized at 750 °C (KNF-750) exhibited the highest adsorption capacity owing to its high aromatic moiety and large specific surface area. Kinetic adsorption by KNF-750 was well fitted with the pseudo-second-order model, with equilibrium attained within 3h. The maximum triclosan adsorption capacity of KNF-750 obtained from the Langmuir model with a high correlation coefficient was 77.4mg/g. Triclosan adsorption sharply decreased at an initial solution pH of 5 because a final solution pH higher than 9 caused dissociation of triclosan. A 90% removal of triclosan was achieved with 4g/L of KNF-750. The adsorption of triclosan was endothermic, with an enthalpy change of 32.8kJ/mol. XPS analysis proved that triclosan was adsorbed on the surface of biochar by the disappearance of inorganic Cl and the appearance of organic Cl.
66. 题目: Chemical, biochemical, and microbiological properties of Technosols produced from urban inorganic and organic wastes
期刊: Journal of Soils and Sediments
作者: T. F. Abbruzzini, A. L. Reyes-Ortigoza, R. J. Alcántara-Hernández, L. Mora, L. Flores, B. Prado
摘要: Purpose The production of Technosols is a sustainable strategy to reuse urban wastes and to regenerate degraded sites. However, little is known regarding the role of the activity of enzymes associated with carbon and nutrients cycling on organic degradation and microbial activity in these soils. Methods A controlled experiment was conducted with Technosols made from construction wastes, wood chips, and compost or compost plus biochar, in order to evaluate their organic matter (OM) degradation potential and functioning through the activity of enzymes and microbial community composition. Results The Technosols had organic carbon contents from 13 to 30 g kg−1, carbon-to-nitrogen ratio from 10 to 20, and available phosphorus from 92 to 376 mg kg−1. The Technosols with biochar and compost had alkaline pH and higher contents of organic carbon and available phosphorus compared to Technosols with compost alone. The mixture of wood chips and compost presented the highest enzyme activities, and might be the most appropriate for Technosol’s production. The mixture of concrete and excavation waste with compost and compost plus biochar displayed a potential for OM decomposition comparable to that of wood chips with compost plus biochar. These results suggest that the bacterial and archaeal fingerprint is similar among the Technosols, although differences are observed in the relative abundances of their taxa. Conclusions Substrate composition affects the processes of OM transformation, microbial biomass activity, and composition. The mixture of wood chips and compost presented the highest enzyme activities during the incubation period, and might be the most appropriate for its application as a Technosol. The mixture of concrete and excavation waste with either compost or compost plus biochar displayed a potential for organic matter decomposition that was comparable to that of the mixture of wood chips with compost plus biochar. The microbial communities in these Technosols are not significantly different yet, but the bioavailability of nutrients derived from the changes in the soil matrix (by adding construction waste and biochar) is influencing soil enzymatic activity.
67. 题目: Co-pyrolysis of sewage sludge/cotton stalks with K2CO3 for biochar production: Improved biochar porosity and reduced heavy metal leaching
期刊: Waste Management
作者: Zhipu Wang, Qingmei Tian, Jing Guo, Ruiqi Wu, Henan Zhu, Hongzhen Zhang
摘要: The co-pyrolysis of sewage sludge and biomass is considered a promising technique for reducing the volume of sewage sludge, adding value, and decreasing the risk associated with this waste. In this study, sewage sludge and cotton stalks were pyrolyzed together with different amounts of K2CO3 to evaluate the potential of chemical activation using K2CO3 for improving the porosity of the biochar formed and immobilizing the heavy metals present in it. It was found that K2CO3 activation effectively improved the pore structure and increased the aromaticity of the biochar. Moreover, K2CO3 activation transformed the heavy metals (Cu, Zn, Pb, Ni, Cr, and Cd) into more stable forms (oxidizable and residual fractions). The activation effect became more pronounced with increasing amount of added K2CO3, eventually resulting in a significant reduction in the mobility and bioavailability of the heavy metals in the biochar. Further analysis revealed that, during the co-pyrolysis process, K2CO3 activation resulted in a reductive atmosphere, increased the alkalinity of the biochar, and led to the formation CaO, CaCO3, and aluminosilicates, which aided the immobilization of the heavy metals. K2CO3 activation also effectively reduced the leachability, and thus, the environmental risks of the heavy metals. Thus, K2CO3 activation can improve the porosity of the biochar derived from sewage sludge/cotton stalks and aid the immobilization of the heavy metals in it.
68. 题目: Effects of permafrost degradation on soil organic matter turnover and plant growth
作者: Lina Che, Muyang Cheng, Libo Xing, Yifan Cui, Luhe Wan
摘要: Continuous climate warming in northeastern China has intensified the melting of permafrost, leading to its degradation. The thawing of permafrost increases the instability of wetland soil organic matter and accelerates decomposition; this will inevitably have a strong impact on the transformation of soil organic matter and the process of vegetation growth. Therefore, the present study used the Xing’an Mountains in Northeast China as the research area. We selected typical marsh areas and analyzed the thickness of the active layer and seasonal frozen soil at different degrees of permafrost degradation. Soil and plant samples (herbs: Carex schumidtii; shrubs: Vaccinium uliginosum; trees: Betula papyrifera) from foliage, roots, and stems were collected at different depths to determine the carbon and nitrogen stable isotope contents in soil and plants. Analysis of variance and multiple linear regression were used to examine the impact of frozen soil degradation on soil organic matter turnover and vegetation growth. The results showed that the thickness of the active layer is increasing, and the amount of seasonal frozen soil is decreasing in the Xing'an Mountains. The δ13C, δ15N, ɛδ13C, and ɛsoil15N values of different depths of permafrost were significantly different (P < 0.05). The foliage, roots, and stems of C. schumidtii, V. uliginosum, and B. papyrifera under different degrees of permafrost degradation were significantly different (P < 0.05), except for the δ13C value of B. papyrifera roots. Soil isotopic composition, and therefore SOM quality, was dependent on the isotopic composition of incoming biomass (foliage, roots, and stems).
69. 题目: Efficient removal of uranium from wastewater using pig manure biochar: understanding adsorption and binding mechanisms
期刊: Journal of Hazardous Materials
作者: Jun Liao, Ling Ding, Yong Zhang, Wenkun Zhu
摘要: In this work, three kinds of biochars (PMBC-H2O, PMBC-PP and PMBC-HP) with excellent adsorption performance were obtained by carbonizing pig manure pre-treated with different agents. These biochars had the ordered mesoporous structures and possessed abundant active functional groups on their surface. The adsorption behaviors of the biochars towards UVI under various conditions were evaluated by batch experiment. The results showed that KMnO4 and H2O2 could enormously improve the adsorption performance of PMBC to UVI. After KMnO4 and H2O2 pretreatment, the maximum adsorption capacities of PMBC-PP (979.3mg/g) and PMBC-HP (661.7mg/g) were about 2.6 and 1.8 times higher than that of PMBC-H2O (369.9mg/g), respectively, which was much higher than previously reported biochar-based materials. Obviously, KMnO4 pretreatment leaded to a higher enhancement than that of H2O2. The removal mechanism of UVI on PMBC-PP was discussed in-depth. The interaction between UVI species and PMBC-PP was mainly ascribed to the abundant active sites on the surface of PMBC-PP. In a word, conversion of pig manure pre-treated with KMnO4 into biochar not only demonstrates that PMBC-PP has great potential in the treatment of actual uranium-containing wastewater, but also provides a method for the rational utilization of pig manure to reduce the pollution.
70. 题目: Do DOM optical parameters improve the prediction of copper availability in vineyard soils?
期刊: Environmental Science and Pollution Research
作者: Frédéric Ouédraogo, Jean-Yves Cornu, Noémie Janot, Christophe Nguyen, Mahaut Sourzac, Edith Parlanti, Laurence Denaix
摘要: Accumulation of copper (Cu) in soils due to the application of fungicides may be toxic for organisms and hence affect winegrowing sustainability. Soil parameters such as pH and dissolved organic matter (DOM) are known to affect the availability of Cu. In this study, we investigated the contribution of chromophoric and fluorescent DOM properties to the prediction of Cu availability in 18 organic vineyard soils in the Bordeaux winegrowing area (France). The DOM parameters, assessed through absorbance and fluorescence analyses, and proxies for Cu availability (total soluble Cu and free ionic Cu2+) were measured in 0.01 M KCl extracts. Total soluble Cu (CuKCl) varied 23-fold while free ionic Cu2+ varied by a factor of 4600 among the soils. DOC concentrations were similar among the soils, but the samples differed in the quality of DOM as assessed by optical spectroscopy. Multilinear regression models with and without DOM quality parameters were investigated to predict Cu availability. The best model for CuKCl successfully explained 83% of variance and included pH, CuT, and two DOM fluorescence quality indices, the FI fluorescence index, which distinguishes between microbial and higher plant origins, and the HIX humification index. For the prediction of Cu2+, pH alone explained 88% of variance and adding DOM parameters did not improve modelling. The two Cu availability proxies were related to pH. This study confirms the prominent role of pH in Cu availability and underlines the importance of DOM quality to better predict Cu solubility.
71. 题目: Collaborative optimization for the performance of ZnO/biochar composites on persulfate activation through plant enrichment-pyrolysis method
期刊: Chemical Engineering Journal
作者: Ruyi Xu, Meng Li, Qian Zhang
摘要: A novel method of plant enrichment for ZnO nanoparticles (ZnO NPs) and pyrolysis was employed to gain the ZnO/biochar (ZnO/BC) composites. Comparing to pristine biochar and two zinc oxides/biochar composites obtained by conventional metal salts impregnation method, here the ZnO/BC exhibited distinct advantages in persulfate (PS) activation for tetracycline hydrochloride (TC) degradation. The activation mechanism analysis revealed that PS accepted electrons from persistent free radicals (PFRs) in ZnO/BC to directly or indirectly generate SO4∙- and HO∙. Coincidentally, ZnO NPs promoted the secretion of total phenols and flavonoids, as precursors of PFRs, which accelerated the formation of more oxygen-centered PFRs with stronger catalytic ability and longer half-life. Moreover, owing to the tight combination of ZnO NPs with internal structures of the plant, higher porosity and large specific surface area in the biochar composites were favorable for reducing the electrochemical impedance of ZnO/BC, which could effectively facilitate the electron transfer process between PFRs and PS. Meanwhile, due to the injection of electrons during PFRs formation, slight narrow in the bandgap brought about the mild enhancement of photocatalytic properties for ZnO NPs. Overall, the method in this research not only provided a new strategy to acquire metal oxide/biochar composites with catalytic ability, but also opened up a novel way to collaboratively optimize the performance of biochar matrix and metal nanoparticles.
72. 题目: Peroxydisulfate activation by digestate-derived biochar for azo dye degradation: Mechanism and performance
期刊: Separation and Purification Technology
作者: Jingxin Liu, Simian Huang, Teng Wang, Meng Mei, Si Chen, Jinping Li
摘要: Peroxydisulfate (PDS) is a low-cost sulfate radical-based oxidant, and carbonaceous material is perceived as efficient and environmentally friendly catalyst for PDS activation. Herein, biochar derived from food waste digestate (FWDB) was prepared, which exhibited excellent potential for removing contaminant due to its unique characteristics. The performance of FWDB for PDS activation was evaluated via the removal of a typical azo dye of reactive brilliant red X-3B, and the mechanism was explored. Under the conditions of FWDB dosage of 0.5 g/L, PDS concentration of 1.5 mM, no adjusting of pH value, and 25 °C, 92.21% of X-3B (initial concentration of 1 g/L) in the solution was removed within 30 min. SO4•−, •OH, O2•−, and 1O2 were identified as the reactive oxygen species (ROS) in this FWDB/PDS system, and the graphitized carbon, doped-N, oxygen-containing groups, and defective sites on the surface of FWDB were answerable for the generation of ROS. The obtained results confirmed the application potential of FWDB in the treatment of organic wastewater, providing an alternative strategy of “treating waste with waste”.
73. 题目: Flow photocatalysis system-based functionalized graphene oxide-ZnO nanoflowers for degradation of a natural humic acid
期刊: Environmental Science and Pollution Research
作者: Ganjar Fadillah, Tawfik A. Saleh, Hanik Munawaroh, Sayekti Wahyuningsih, Ari Handono Ramelan
摘要: The functionalized graphene oxide-ZnO (fGO/ZnO) nanoflower composites have been studied as a photocatalyst material for flow photodegradation of humic acid (HA) in real samples. The fGO/ZnO nanoflower was prepared via hydrothermal methods. The chemical and physical properties of the synthesized photocatalyst have been carried out by several techniques, including X-ray diffraction (XRD), scanning electron microscope-energy-dispersive spectrometer (SEM-EDS), Fourier transform infrared (FTIR), and UV-Vis spectrophotometer. The photocatalytic study of degradation of HA by flow system is reported. The optimum condition for degradation was found at pH 4.0, a flow rate of 1 mL min−1, and a light intensity of 400 mW cm−2. The degradation efficiency of HA also was influenced by several anion or cation concentration ratios on the system. This method was applied for the degradation of HA in extracted natural HA from the soil, and the efficiency achieved at 98.5%. Therefore, this research provides a low-cost, fast, and reusability method for HA degradation in the environment.
74. 题目: Climate change and drinking water from Scottish peatlands: Where increasing DOC is an issue?
期刊: Journal of Environmental Management
作者: Anna Ferretto, Rob Brooker, Robin Matthews, Pete Smith
摘要: Increasing levels of dissolved organic carbon (DOC) have been detected in the last decades in water bodies of the Northern hemisphere, and climate change might fuel this rise. For drinking water reservoirs located in peatland catchments, already subjected to elevated amounts of DOC that needs to be removed, this might pose a further problem. Scotland is predicted to face warmer temperatures and a change in rainfall patterns, which will result in more frequent and severe summer droughts and in heavier winter precipitation. These conditions are not ideal for peatlands, which may undergo a drastic reduction in area. Using two bioclimatic envelope models (Blanket bog Tree model and Lindsay Modified model) that project blanket bog distribution in Scotland in the 2050s, we extracted the area of blanket bog that is at risk of loss. Assuming that part of the carbon stored in this area is likely to be lost, we calculated how much of it could be added to DOC in catchments that contain public drinking water reservoirs each year. This analysis is a first estimate of the risk for the provision of drinking water from peatlands in Scotland due to climate change. The aim is to identify the catchments that may face the highest consequences of future climates in terms of the concentration of DOC ([DOC]), where more sophisticated water treatments might be needed. Our results show a great variability among the catchments, with only a few being unaffected by this problem, whereas others could experience substantial seasonal increase in [DOC]. This highlights the necessity to frequently monitor DOC levels in the reservoirs located in catchments where the major problems could arise, and to take the necessary measures to reduce it. Given that peatland condition and vegetation cover play a fundamental role in influencing DOC losses, this study also offers an indication of where peatland restoration might be useful to counteract the projected DOC increase and bring the highest benefits in terms of safe drinking water provision.
75. 题目: Iron in boreal river catchments: Biogeochemical, ecological and management implications
期刊: Science of The Total Environment
作者: K. Heikkinen, M. Saari, J. Heino, A.-K. Ronkanen, P. Kortelainen, S. Joensuu, A. Vilmi, S.-M. Karjalainen, S. Hellsten, M. Visuri, H. Marttila
摘要: Iron (Fe) is an important element in aquatic ecosystems worldwide because it is intimately tied with multiple abiotic and biotic phenomena. Here, we give a survey of manifold influences of Fe, and the key factors affecting it in the boreal catchments and their waters. It includes the perspectives of biogeochemistry, hydrology, ecology, and river basin management. We emphasize views on the dynamics and impacts of different forms of Fe in riverine environments, including organic colloids and particles, as well as inorganic fractions. We also provide perspectives for land use management in boreal catchments and suggest guidelines for decision making and water management. Based on our survey, the main emphases of water protection and management programs should be (i) prevention of Fe mobilization from soil layers by avoiding unnecessary land-use activities and minimizing soil disturbance in high-risk areas; (ii) disconnecting Fe-rich ground water discharge from directly reaching watercourses; and (iii) decreasing transport of Fe to watercourses by applying efficient water pollution control approaches. These approaches may require specific methods that should be given attention depending on catchment conditions in different areas. Finally, we highlight issues requiring additional research on boreal catchments. A key issue is to increase our understanding of the role of Fe in the utilization of DOM in riverine food webs, which are typically highly heterotrophic. More knowledge is needed on the metabolic and behavioral resistance mechanisms that aquatic organisms, such as algae, invertebrates, and fish, have developed to counter the harmful impacts of Fe in rivers with naturally high Fe and DOM concentrations. It is also emphasized that to fulfil the needs presented above, as well as to develop effective methods for decreasing the harmful impacts of Fe in water management, the biogeochemical processes contributing to Fe transport from catchments via rivers to estuaries should be better understood.
76. 题目: The Grain for Green project eliminated the effect of soil erosion on organic carbon on China’s Loess Plateau between 1980 and 2008
期刊: Agriculture, Ecosystems & Environment
作者: Jingjing Wang, Zhipeng Liu, Jianlun Gao, Lugato Emanuele, Yongqing Ren, Mingan Shao, Xiaorong Wei
摘要: Erosion and vegetation change intertwine in affecting soil organic carbon (SOC), yet their separate effects have not been explicitly disentangled, precluding a precise assessment of terrestrial carbon cycling and reliable application of Earth system models. Herein, we assessed the changes in the SOC, normalized difference vegetation index (NDVI) and soil erosion between 1980 and 2008 on China’s Loess Plateau, a region that suffered severe soil erosion, prompting the implementation of the Grain for Green project in 1999 to reduce soil erosion and rehabilitate degraded land. We established structural equation model and conducted Sobol sensitivity analysis to evaluate how soil erosion and the Grain for Green project-induced vegetation change altered the temporal patterns of SOC at the regional scale. We showed that SOC was not significantly changed, while the NDVI increased and the soil erosion decreased between 1980 and 2008. The Grain for Green project contributed 67% and 100% to the changes in the NDVI and soil loss, respectively. Additionally, changes in the NDVI and soil loss were negatively correlated and showed significant spatial variation. The change in SOC was negatively affected by soil erosion before the Grain for Green project but positively affected by the increased vegetation after the Grain for Green project. The positive effect of the Grain for Green project on SOC after 1999 offset the negative effect of erosion between 1980 and 1999. Additionally, the SOC change and its response to vegetation and erosion were closely affected by climate and clay content. These results suggest that the Grain for Green project eliminated the negative effect of soil erosion on SOC on China’s Loess Plateau.
77. 题目: Role of proteins and soluble peptides as limiting components during the co-composting of agro-industrial wastes
期刊: Journal of Environmental Management
作者: M.D. Pérez-Murcia, E. Martínez-Sabater, M.A. Domene, A. González-Céspedes, M.A. Bustamante, F.C. Marhuenda-Egea, X. Barber, D.B. López-Lluch, R. Moral
摘要: The agri-food industry is at the centre of the circular economy, since the co-composting of its residual flows allows their management and adds value producing fertilisers. In this work, six composting piles were prepared combining agri-food sludge (AS), different fresh vegetable wastes (pepper waste (P), tomato waste (T), and leek waste (L), and, as bulking agents, vine shoot pruning (VS), garlic stalks (GS) and avocado leaves (AL)). Classical physico-chemical and chemical determinations and advanced instrumental methods (excitation-emission fluorescence (EEM) and gravimetric (TG, DTG and DTA) techniques) were used and compared to assess organic matter evolution and evaluate the quality of the composts obtained. The thermal profiles of the composting processes were viable to show the stabilization of the agri-food sludge with the different materials tested in the mixtures, reaching adequate levels of stabilization of organic matter. Preferential degradation of peptides and proteins was observed by fluorescence. This seemed to induce a limitation in the biodegradation of the remaining organic matter, indicating that these biomolecules are key in composting dynamics, acting as limiting components during the process. The results from thermogravimetric analysis indicated the degradation of labile compounds (e.g., carbohydrates and proteins), the most recalcitrant material becoming predominant at the maturity stage of the composting process. The rise in the thermogravimetric parameter R2 was associated with the increase in the concentration of more refracting compounds, which need more energy for their decomposition.
78. 题目: Acidification impacts on the molecular composition of dissolved organic matter revealed by FT-ICR MS
期刊: Science of The Total Environment
作者: Huixia Han, Yujie Feng, Jing Chen, Qiaorong Xie, Shuang Chen, Ming Sheng, Shujun Zhong, Wan Wei, Sihui Su, Pingqing Fu
摘要: Solid-phase extraction (SPE) is a traditional pretreatment procedure widely used for dissolved organic matter (DOM) desalination and enrichment prior to the Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis, and the extracts are usually acidified to pH = 2 with hydrochloric acid (HCl) before passing through the cartridge. However, little is known about the effects of acidification on the integrity and molecular composition of DOM. Here, the differences in the molecular compositions in acidified and nonacidified DOM samples of soil, seawater and atmospheric aerosol were performed by FT-ICR MS. The results showed that the quantity and intensity of aromatic compounds with high oxygen content (e.g., polyphenols, tannin-like and highly oxygenated organic compounds) were greatly enhanced after acidification, while highly saturated compounds (lipid-like and aliphatic/peptide-like) were absent. The underlying reason is the variation of solubility and hydrolysis of DOM under acidic conditions. Meanwhile, the effect of acidification on the molecular composition of DOM was also dependent on their original environmental media. Based on these results, we suggest that the extracts of soil samples are selectively acidified according to the focus of research, while the extract is acidified for seawater samples and the pH of the extract can be unadjusted for aerosol samples before the SPE procedure. These findings provide a reference for the selection of suitable pretreatment methods for different experimental purposes and for the comprehensive characterization of samples with different properties.
79. 题目: Imbalanced nitrogen–phosphorus input alters soil organic carbon storage and mineralisation in a salt marsh
作者: Juanyong Li, Guangxuan Han, Guangmei Wang, Xiaoling Liu, Qiqi Zhang, Yawen Chen, Weimin Song, Wendi Qu, Xiaojing Chu, Peiguang Li
摘要: A large imbalance in soil nitrogen (N) and phosphorus (P) inputs induced by anthropogenic activities is anticipated to profoundly influence soil carbon (C) budgets in salt marshes. In this study, we hypothesized that imbalances in the nitrogen–phosphorus (N–P) input would result in the nonlinear response of soil organic carbon (SOC) content, fractions and mineralization to the N–P input ratio. We applied three N–P input ratios (low (5:1), medium (15:1), high (45:1)) in a salt marsh of the Yellow River Delta (YRD) for four years (in which N added increased from 8.67 to 26.01 g N m−2 y−1 and P added decreased from 1.73 to 0.58 g P m−2 y−1) and quantified their impacts on SOC fractions and SOC mineralisation. The control treatment did not receive fertilization. The results showed that the N and P input led to overall increases in the availability of soil nutrients (i.e., inorganic N (IN) and available P (AP)), stimulation of plant biomass and changes of microbial community structure (i.e., γ- and δ-Proteobacteria and Acidobacteria). N and P input increased soil dissolved organic carbon (DOC) and decreased aromatic DOC components through improving N availability and stimulating plant growth. Notably, though, there may be a threshold N–P input ratio between 15:1 and 45:1 that, once crossed, triggers the loss of SOC. Appropriate increase in N availability induced by low and medium N-P input ratios would stimulate the SOC mineralization. However, excessive N-P input ratio would reduce SOC mineralization. Path analysis indicated that N–P input ratios dominantly regulate SOC mineralisation by changing soil DOC and microbial biomass (MBC)contents and microbial community structure. Thus, we speculate that the continuous increase in N input causes a growing N–P imbalance that reduces SOC stocks, despite a reduction in SOC mineralisation.
80. 题目: Phosphate enhanced uranium stable immobilization on biochar supported nano zero valent iron
期刊: Journal of Hazardous Materials
作者: Yang Ruan, Huimin Zhang, Zijing Yu, Zenghui Diao, Gang Song, Minhua Su, Li’an Hou, Diyun Chen, Shuao Wang, Lingjun Kong
摘要: Uranium (U) immobilization from wastewater by zero valent iron (ZVI) was widely concerned through reduction and surface adsorption. Releasing of U due to re-oxidation of U(IV) into U(VI) limited the application of ZVI in U decontamination. In this work, a kind of biochar supported nano zero valent iron (Fe/BC(900)) was obtained by carbothermal reduction of starch mixed with ferric nitrate at 900oC. U immobilization behavior by Fe/BC(900) in the presence of phosphate (P) was investigated. The U immobilization reaction was adjusted by controlling the sequence of U, Fe/BC(900) and P. U immobilization efficiency was enhanced to 99.9% in the presence of P. Reaction sequence of U, Fe/BC(900) and P influenced the U immobilization efficiency, which followed the order of (U-P)+Fe/BC(900)> (U- Fe/BC(900))+P> U+Fe/BC(900)> (P-Fe/BC(900))+U. P and nZVI both contributed to enhancing U immobilization through precipitation of uranyl-P and reductive co-precipitate (U(IV) in a wide pH range. The released Fe ions could precipitate with uranyl and phosphate. Consumption of P and nZVI in the (P-Fe/BC(900))+U system limited U immobilization ability. The precipitate is highly dependent on U, P and Fe elements. U desorption in (U-P)+Fe/BC(900) system was not observed with stability.