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24701. 题目: Biochar increases ¹⁵N fertilizer retention and indigenous soil N uptake in a cotton-barley rotation system
文章编号: N19090505
期刊: Geoderma
作者: Zhi Wang, Zhen Wang, Ying Luo, Ya-nan Zhan, Ya-li Meng, Zhi-guo Zhou
更新时间: 2019-09-05
摘要: Biochar amendments can modify fertilizer nitrogen (N) availability in soil and crop N uptake. However, how biochar addition affects crop N uptake and fertilizer N recovery under various N levels is not yet well understood. To address this question, we conducted a two-season [cotton (Gossypium hirsutum L.)-barley (Hordeum vulgare L.) rotation] pot experiment that included four N fertilizer rates (0, 75, 150, and 300 kg N ha⁻¹, supplied as urea-¹⁵N) combined with two straw-biochar rates (0 and 15 t ha⁻¹). Soil properties, plant root morphology, N uptake, and biomass yield were studied. Biochar addition decreased soil inorganic N content but increased urea-N retention at cotton harvest, leading to 32% of the applied urea-N accumulating in soil compared with 27% without biochar, averaged across fertilizer N rates. Use of ¹⁵N fertilizer showed that biochar increased plant uptake of indigenous soil N, not fertilizer N. An obvious decrease in urea-¹⁵N recovery induced by biochar was observed at 75 kg N ha⁻¹, but not at 150 or 300 kg N ha⁻¹. The efficiency of urea-¹⁵N recovery by plants (¹⁵NRE, 34–45%), measured using the tracer method, was much lower than that measured using the traditional non-isotope method (NRE, 67–96%). At barley harvest, 2–5% of the urea-N, applied in the first season, was taken up by plants, and 12–19% remained in soils receiving biochar. We concluded that straw-biochar addition increased soil ¹⁵N fertilizer retention and plant N uptake of indigenous soil N, not fertilizer N, and the increased indigenous soil N uptake persisted into the second cropping season.
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24702. 题目: Glomalin-related soil protein affects soil aggregation and recovery of soil nutrient following natural revegetation on the Loess Plateau
文章编号: N19090504
期刊: Geoderma
作者: Hongfei Liu, Xiukang Wang, Chutao Liang, Zemin Ai, Yang Wu, Hongwei Xu, Sha Xue, Guobin Liu
更新时间: 2019-09-05
摘要: The glomalin-related soil protein (GRSP) is an important fraction of soil organic carbon (SOC) and soil nitrogen (N), and is important for stabilization of SOC and soil aggregates. However, the effects of natural restoration on the concentration and allocation of GRSP differ for different soil aggregate sizes, and how size further affects SOC and soil N restoration, and stabilization of SOC and soil aggregates is not well understood. Here, we present the first characterization of the distribution of GRSP fractions and soil nutrients in soil aggregates following natural restoration by choosing fields of 0, 7, 12, 17, 22, 32 years after cropland abandonment, and a natural grassland as reference. GRSP concentration increased most in microaggregates after 32 years of natural restoration. The processes of rapid accumulation of GRSP (22 to 32 years) occurred simultaneously with the formation of macroaggregates, reduction of microaggregates, and rapid increase of mean weight diameter (22 to 32-years). The soil aggregate stability and contents of GRSP, SOC, labile carbon, total N and phosphorus in each soil aggregate fraction significantly increased in the late stage of natural restoration (22 to 32 years). The most recalcitrant carbon fraction in microaggregates significantly increased between 7 and 32 years (0.887 g kg⁻¹). Our study suggests that abandoning farmland is effective for the restoration of GRSP, soil nutrients and structure and that microaggregates promote the accumulation of recalcitrant carbon and increase the stability of SOC largely through its ability to retain GRSP.

24703. 题目: Effects of intensities and cycles of heating on mineralization of organic matter and microbial community composition of a Mollisol under different land use types
文章编号: N19090503
期刊: Geoderma
作者: Andong Shi, Xuan Zhou, Shuihong Yao, Bin Zhang
更新时间: 2019-09-05
摘要: Soil heating at high temperatures was often found in greenhouse agriculture and high temperature extremes are predicted to occur more frequently in future climate. Yet, the influences of soil heating on soil organic matter decomposition, N mineralization, and the shift in microbial community composition are not well studied, particularly over multiple heating cycles and among different land use types. The main objectives of this study were 1) to investigate the effects of multiple heating cycles on soil respiration, N mineralization and soil microbial community composition, 2) to explore the relationships between soil microbial functions and community composition following heating cycles, and 3) to examine the influence of different land use types on soil microbial functions and community composition. The soils were sampled from an arable land, a forestland, and a grassland, and subjected to 25 °C constantly and to 40 or 50 °C for 18 h before being kept at 25 °C within 10 days for 3 cycles. At all temperature treatments, the forestland and the grassland had higher soil respiration rates, microbial biomasses and soil mineral N concentrations, compared to the arable land. In addition, the forestland and the grassland showed similar patterns of soil microbial community composition characterized by phospholipid fatty acid profiles (PLFA), but differed from that in the arable land. The soil respiration rates were enhanced by the increases in heating temperatures, and soil microbial biomass carbon (C) and N concentrations was reduced after heating at 40 °C, compared to these in the control treatment, and the reduction became more pronounced in heating treatment at 50 °C. With the increasing number of heating cycles, the soil respiration rate decreased after heating, but soil mineral N concentration was gradually enhanced, particularly in heating treatment at 50 °C. The principal component analysis of PLFAs demonstrated that soil microbial community composition shifted dramatically between days 21 and 30 (cycle 3), and between days 11 and 21 (between cycles 2 and 3, respectively), compared to that between days 1 and 11 (between cycles 1 and 2). The shift was consistent for all the land use types via PC1, but differed between the arable land and other land use types via PC2. Therefore, our findings suggested that cyclic heating drove changes in microbial composition, uncoupled soil C and N cycling during soil organic matter decomposition and could lead to a rapid decline of soil fertility and environmental quality under heating stresses.

24704. 题目: Removal of Arsenic(III) from water using magnetite precipitated onto Douglas fir biochar
文章编号: N19090502
期刊: Journal of Environmental Management
作者: Chanaka M. Navarathna, Akila G. Karunanayake, Sameera R. Gunatilake, Charles U. Pittman, Felio Perez, Dinesh Mohan, Todd Mlsna
更新时间: 2019-09-05
摘要: Magnetic Fe₃O₄/Douglas fir biochar composites (MBC) were prepared with a 29.2% wt. Fe₃O₄ loading and used to treat As(III)-contaminated water. Toxicity of As(III) (inorganic) is significantly greater than As(V) and more difficult to remove from water. Removal efficiency was optimized verses pH, contact time and initial concentration. Column sorption and regeneration were also studied. Adsorption kinetics data best fitted the pseudo second order model (R² > 0.99). Adsorption was analyzed with three isotherm models at 20, 25 and 40 °C. The Sips isotherm showed the best fit at 25 °C with a 5.49 mg/g adsorption capacity, which is comparable with other adsorbents. MBC gave faster kinetics (~1–1.5 h) at pH 7 and ambient temperature than previous adsorbents. The Gibbs free energy (ΔG) of this spontaneous As(III) adsorption was −35 kJ/mol and ΔH = 70 kJ/mol was endothermic. Experiments were performed on industrial and laboratory wastewater samples in the presence of other co-existing contaminants (pharmaceutical residues, heavy metals ions and oxi-anions). The composite reduced the arsenic concentrations below the WHO's safe limit of 0.2 mg/L for waste water discharge. X-ray photoelectron spectroscopy (XPS) studies found As(III) and less toxic As(V) on Fe₃O₄ surfaces indicating adsorbed (or adsorbing) As(III) oxidation occurred upon contact with O₂ and possibly dissolved Fe(III) or upon drying under oxic conditions. Under anoxic conditions magnetite to maghemite transformation drives the oxidation. A pH-dependent surface chemisorption mechanism was proposed governing adsorption aided by XPS studies vs pH.
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24705. 题目: pH and exchangeable aluminum are major regulators of microbial energy flow and carbon use efficiency in soil microbial communities
文章编号: N19090501
期刊: Soil Biology and Biochemistry
作者: Davey L. Jones, Emily C. Cooledge, Frances C. Hoyle, Robert I. Griffiths, Daniel V. Murphy
更新时间: 2019-09-05
摘要: The microbial partitioning of organic carbon (C) into either anabolic (i.e. growth) or catabolic (i.e. respiration) metabolic pathways represents a key process regulating the amount of added C that is retained in soil. The factors regulating C use efficiency (CUE) in agricultural soils, however, remain poorly understood. The aim of this study was to investigate substrate CUE from a wide range of soils (n = 970) and geographical area (200,000 km²) to determine which soil properties most influenced C retention within the microbial community. Using a ¹⁴C-labeling approach, we showed that the average CUE across all soils was 0.65 ± 0.003, but that the variation in CUE was relatively high within the sample population (CV 14.9%). Of the major properties measured in our soils, we found that pH and exchangeable aluminum (Al) were highly correlated with CUE. We identified a critical pH transition point at which CUE declined (pH 5.5). This coincided exactly with the point at which Al³⁺ started to become soluble. In contrast, other soil factors [e.g. total C and nitrogen (N), dissolved organic C (DOC), clay content, available calcium, nitrogen, phosphorus (P) and sulfur (S), total base cations] showed little or no relationship with CUE. We also found no evidence to suggest that nutrient stoichiometry (C:N, C:P and C:S ratios) influenced CUE in these soils. Based on current evidence, we postulate that the decline in microbial CUE at low pH and high Al reflects a greater channeling of C into energy intensive metabolic pathways involved in overcoming H⁺/Al³⁺ stress (e.g. cell repair and detoxification). The response may also be associated with shifts in microbial community structure, which are known to be tightly associated with soil pH. We conclude that maintaining agricultural soils above pH 5.5 maximizes microbial energy efficiency.
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24706. 题目: Peroxymonosulfate Oxidizes Amino Acids in Water without Activation
文章编号: N19090417
期刊: Environmental Science & Technology
作者: Mercedes Ruiz, Yi Yang, Christian A. Lochbaum, Daniel Graham Delafield, Joseph J. Pignatello, Lingjun Li, Joel A. Pedersen
更新时间: 2019-09-04
摘要: A variety of peptidic and proteinaceous contaminants (e.g., proteins, toxins, pathogens) present in the environment may pose risk to human health and wildlife. Peroxymonosulfate is a strong oxidant (EH0 = 1.82 V for HSO5–, the predominant species at environmental pH values) that may hold promise for the deactivation of proteinaceous contaminants. Relatively little quantitative information exists on the rates of peroxymonosulfate reactions with free amino acids. Here, we studied the oxidation of 19 of the 20 standard proteinogenic amino acids (all except cysteine) by peroxymonosulfate without explicit activation. Reaction half-lives at pH 7 ranged from milliseconds to hours. Amino acids possessing sulfur-containing, heteroaromatic, or substituted aromatic side chains were the most susceptible to oxidation by peroxymonosulfate, with rates of transformation decreasing in the order methionine > tryptophan > tyrosine > histidine. The rate of tryptophan oxidation did not decrease in the presence of an aquatic natural organic matter. Singlet oxygen resulting from peroxymonosulfate self-decomposition, while detected by electron paramagnetic resonance spectroscopy, was unlikely to be the principal reactive species. Our results demonstrate that peroxymonosulfate is capable of oxidizing 19 amino acids without explicit activation and that solvent-exposed methionine and tryptophan residues are likely initial targets of oxidation in peptides and proteins.

24707. 题目: Antimonite Binding to Natural Organic Matter: Spectroscopic Evidence from a Mine Water Impacted Peatland
文章编号: N19090416
期刊: Environmental Science & Technology
作者: Johannes Besold, Anne Eberle, Vincent Noël, Katharina Kujala, Naresh Kumar, Andreas C Scheinost, Juan Lezama Pacheco, Scott Fendorf, Britta Planer-Friedrich
更新时间: 2019-09-04
摘要: Peatlands and other wetlands are sinks for antimony (Sb), and solid natural organic matter (NOM) may play an important role in controlling Sb binding. However, direct evidence of Sb sequestration in natural peat samples is lacking. Here, we analyzed solid phase Sb, iron (Fe), and sulfur (S) as well as aqueous Sb speciation in three profiles up to a depth of 80 cm in a mine water impacted peatland in northern Finland. Linear combination fittings of extended X-ray absorption fine structure spectra showed that Sb binding to Fe phases was of minor importance and observed only in the uppermost layers of the peatland. Instead, the dominant (to almost exclusive) sequestration mechanism was Sb(III) binding to oxygen-containing functional groups, and at greater depths, increasingly Sb(III) binding to thiol groups of NOM. Aqueous Sb speciation was dominated by antimonate, while antimonite concentrations were low, further supporting our findings of much higher reactivity of Sb(III) than Sb(V) toward peat surfaces. Insufficient residence time for efficient reduction of antimonate to antimonite currently hinders higher Sb removal in the studied peatland. Overall, our findings imply that Sb(III) binding to solid NOM acts as an important sequestration mechanism under reducing conditions in peatlands and other high-organic matter environments.

24708. 题目: Natural groundwater nutrient fluxes exceed anthropogenic inputs in an ecologically impacted estuary: lessons learned from Mobile Bay, Alabama
文章编号: N19090415
期刊: Biogeochemistry
作者: Daniel Montiel, Alexander F. Lamore, Jackson Stewart, W. Joe Lambert, Jacob Honeck, Yuehan Lu, Olivia Warren, Dini Adyasari, Nils Moosdorf, Natasha Dimova
更新时间: 2019-09-04
摘要: In this study we evaluated the magnitude and seasonal variations of natural and anthropogenic fluxes of inorganic (NO₃⁻, NH₄⁺, and PO₄³⁻) and organic (DON and dissolved organic carbon) nutrients delivered by submarine groundwater discharge (SGD) and rivers to the fourth largest estuary in the USA, Mobile Bay in Alabama. To identify the sources of SGD-nutrient in the estuary and their subsurface biogeochemical transformation, we applied a multi-method approach that combines geochemical nutrient (N and P) mass-balances, stable isotopes (nitrate (updelta^{15} { ext{N}}_{{{ ext{NO}}_{3} }}) and (updelta^{18} { ext{O}}_{{{ ext{NO}}_{3} }}) and sediment organic matter δ¹³C_org and δ¹⁵N_org) signatures, microbial sequencing analyses, dissolved organic matter source-composition, and shallow estuarine sediment lithological analyses. We found that during dry seasons SGD delivered nearly a quarter of the total nutrient inputs to Mobile Bay. These SGD fluxes were anoxic and N was delivered to the bay almost entirely as NH₄⁺ and DON, which represented more than half of the total NH₄⁺ and almost one fifth of the total DON inputs to the bay. We further observed that these significant SGD-derived N fluxes occurred exclusively to the east shore of Mobile Bay, historically impacted by hypoxia and large-scale fish kills known as “Jubilees”. We demonstrate here that although the Mobile Bay coastal area is largely developed and anthropogenic influences are well documented, a shallow peat layer identified only on the east shore serves as the main source of the exceptionally high NH₄⁺ and DON fluxes. We found that the high groundwater NO₃⁻ concentrations observed further inland from over-fertilization also identified by previous studies, decreased dramatically as groundwater percolated through the intertidal zone of the coastal aquifer. The microbial community identified in the coastal sediments suggests that denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were the main processes responsible for this extensive removal and transformation of anthropogenic N, respectively. Furthermore, we found no significant anthropogenic inputs from manure or sewage waste to the bay. These findings show that natural sources of nutrients can outcompete anthropogenic inputs despite extensive development of the coastal area. We hypothesize that similar subsurface biogeochemical nutrient transformations can occur in other shallow estuaries of the northern Gulf of Mexico and worldwide.

24709. 题目: Climate warming alters subsoil but not topsoil carbon dynamics in alpine grassland
文章编号: N19090414
期刊: Global Change Biology
作者: Juan Jia, Zhenjiao Cao, Chengzhu Liu, Zhenhua Zhang, Li Lin, Yiyun Wang, Negar Haghipour, Lukas Wacker, Hongyan Bao, Thorston Dittmar, Myrna J. Simpson, Huan Yang, Thomas W. Crowther, Timothy I. Eglinton, Jin‐Sheng He, Xiaojuan Feng
更新时间: 2019-09-04
摘要: Subsoil contains more than half of soil organic carbon (SOC) globally and is conventionally assumed to be relatively unresponsive to warming compared to the topsoil. Here we show substantial changes in carbon allocation and dynamics of the subsoil but not topsoil in the Qinghai‐Tibetan alpine grasslands over 5 years of warming. Specifically, warming enhanced the accumulation of newly synthesized (¹⁴C‐enriched) carbon in the subsoil slow‐cycling pool (silt‐clay fraction) but promoted the decomposition of plant‐derived lignin in the fast‐cycling pool (macroaggregates). These changes mirrored an accumulation of lipids and sugars at the expense of lignin in the warmed bulk subsoil, likely associated with shortened soil freezing period and a deepening root system. As warming is accompanied by deepening roots in a wide range of ecosystems, root‐driven accrual of slow‐cycling pool may represent an important and overlooked mechanism for a potential long‐term carbon sink at depth. Moreover, given the contrasting sensitivity of SOC dynamics at varied depths, warming studies focusing only on surface soils may vastly misrepresent shifts in ecosystem carbon storage under climate change.

24710. 题目: Use of fatty acids as tracer of organic matter input associated with level of land urbanization
文章编号: N19090413
期刊: Environmental Science and Pollution Research
作者: Angela Ethelis Jiménez Martínez, Aluana Schleder, Juan Sanez, Anelize Bahniuk, Sandro Froehner
更新时间: 2019-09-04
摘要: Suspended sediments (SSs) were examined regarding the content of fatty acids (FAs) to associate them with sources of soil entry into the river. The source of organic matter was traced through fatty acid distribution, as well as erosion. Also, TOC, TN, and TOC/NT were used to support the results of FAs. For this, a tropical river was chosen to understand the main source of input considering the level of land occupation along the river. The Barigui river, in southern Brazil, was segmented in four distinct areas regarding the soil occupation (P1, P2, P3, and P4). Nine sampling campaigns were conducted from Nov/2014 to Nov/2015 using a time-integrated sampler. Site P1 has the lowest level of urbanization and showed the lowest concentration of FAs (16.35 μg⁻¹). In contrast, site P4, the most urbanized, showed the highest content of fatty acids, including those associated with erosion, 378.53 μg g⁻¹, specifically those with long chains. The mean concentrations of the saturated fatty acids (FAs) was 283.40 μg g⁻¹, monounsaturated fatty acids (MUFAs) was 79.46 μg g⁻¹, and polyunsaturated fatty acids (PUFAs) was 15.66 μg g⁻¹. Twenty-seven fatty acids were examined, nevertheless C15:0, C16:0, C18:0, and C18:1ω9 prevailed in all samples. Generally, those acids indicate sewage inputs. Statics analyses were used to find the relation between the source of organic matter (autochthonous, allochthones, and anthropogenic) and FAs. Finally, the input of organic matter is associated with land occupation, which can be distinguished by FA distribution.

24711. 题目: Effect of humic acid on the sedimentation and transport of nanoparticles silica in water-saturated porous media
文章编号: N19090412
期刊: Journal of Soils and Sediments
作者: Mo Zhang, Duo Li, Zhi Ye, Shiqi Wang, Nan Xu, Fang Wang, Shouqing Liu, Jianping Chen, Huajie Gu
更新时间: 2019-09-04
摘要: Purpose: Nano silicon particles (nSiO₂) is one of the most widely used industrial engineered nanomaterials (ENMs). The extensive applications of nSiO₂ may pose potential risks to aquatic ecosystems and human health. Humic acid (HA) is a major component of soil and water that exists widely in the natural environment and adsorbs to the surface of nanoparticles, which affects the fate and transport of ENMs in soil. Therefore, it triggers the necessity to study the chemical reaction of HA controlling the sedimentation and transport of nSiO₂. Materials and methods: The sedimentation kinetics and transport breakthrough curves of nSiO₂ with/without HA in water-saturated porous media were studied in two electrolyte (NaCl and CaCl₂) solutions. The likely mechanisms were explored with both multiple technologies and numerical modeling including TEM-EDX, particle size distribution, zeta potentials, and the two-site kinetic attachment model (TSKAM). Results and discussion: Our experimental results showed that the existence of HA generally increased the suspensivity and the transportability of nSiO₂ in NaCl and CaCl₂ solutions in packed sand columns at acidic pH. This result was attributed to the HA adsorption leading to the more negatively charged surface and the smaller size of nSiO₂ aggregates. However, the formation of coordination complexes associated with larger cluster among nSiO₂ between HA and Ca²⁺ contributed to the increased sedimentation of nSiO₂ at alkaline pH. Subsequently, the presence of HA inhibited the transport of nSiO₂ in CaCl₂ solution at pH 9.0. Comparably, in NaCl at pH 9.0, HA showed the negligible effect on the nSiO₂ deposition in sand. Both the attachment and detachment parameters, which were obtained from fitting the breakthrough curves of ENMs using the TSKAM, could be used to well describe the transport behavior of nSiO₂ with HA under various conditions. In particular, the irreversible attachment parameters at site 2 on sand were positively related to the retention of nSiO₂ with HA. Conclusions: The fate and transport of nSiO₂ can be distinctly affected by HA depending on the ion composition, ion strength, and pH in soil. This study will provide insights for assessing the mobility of nSiO₂ with HA in subsurface soil and aquatic environments.

24712. 题目: Differential responses of soil N₂O to biochar depend on the predominant microbial pathway
文章编号: N19090411
期刊: Applied Soil Ecology
作者: Cheng Ji, Shuqing Li, Yajun Geng, Yingcheng Miao, Ying Ding, Shuwei Liu, Jianwen Zou
更新时间: 2019-09-04
摘要: Biochar amendment has been proposed as a potential strategy to reduce soil nitrous oxide (N₂O) emissions, although experimental studies have generated inconsistent results on N₂O emissions following biochar amendment. Differential responses of soil N₂O to biochar amendment may depend on soil microbial functional genes abundance and abiotic properties. Here we sampled three types of soil from fields under long-term cultivation of green tea (TG), film greenhouse vegetable cabbage (GV) and Jerusalem artichoke (JA), respectively. We conducted a microcosm experiment to examine N₂O emissions from the different soils following biochar amendment. Results showed that biochar amendment increased N₂O emissions from the GV soil while decreasing N₂O emissions from the TG and JA soils in the presence of nitrogen fertilizer. Biochar amendment increased soil pH and C/N ratio across the three soils. Quantitative PCR (qPCR) analysis showed that biochar amendment also consistently increased the abundances of AOB and nosZ genes but decreased the AOA abundances for all the soils, while the effects of biochar on the abundances of nirK and nirS genes differed between the soils. Our results suggest that biochar amendment can affect the processes of both ammonia oxidation and reduction of N₂O to N₂ for all the soils and the net effect of biochar on N₂O emissions depended on the predominant process in a specific soil. Biochar-induced increase in N₂O emissions in the GV soil was largely attributed to the stimulated nitrification rate, which was primarily driven by AOB. Biochar-induced decreases in N₂O emissions in the TG and JA soils were linked to the increased nosZ gene abundances. Overall, the effectiveness of biochar for mitigating N₂O emissions is linked to its dominant N₂O production pathway in soils.

24713. 题目: Activation of persulfate with biochar for degradation of bisphenol A in soil
文章编号: N19090410
期刊: Chemical Engineering Journal
作者: Junguang Liu, Shaojun Jiang, Dongdong Chen, Guangling Dai, Dongyang Wei, Yuehong Shu
更新时间: 2019-09-04
摘要: In this study, a new alternative activator, biochar (BC) pyrolyzed by waste biomass—lychee branch, was applied in persulfate (PS) -based remediation for bisphenol A (BPA) in soils. Radical species, solution pH, dose of PS and BC were studied to evaluate the performance of PS activation by BC to degrade BPA in aqueous solution. The results show that BC can efficiently activate PS to generate sulfate radicals and hydroxyl radicals to degrade BPA high efficiently. The increase of PS and BC dosage can increase BPA removal rate, and a lower pH is benefit for the BPA degradation in aqueous solution. In addition, the degradation intermediates of BPA were characterized and the degradation pathways were proposed. Furthermore, the PS/BC system is most efficient for BPA degradation compared with other oxidants. For soil spiked with 31.93 mg kg⁻¹ BPA, BC can also activate PS and degrade BPA effectively. The increase of BC and PS dose cannot always increase BPA degradation because of the competition of readily oxidizable matter introduced by BC itself and/or quenching of sulfate radicals. During BPA degradation in soil, the pH value drops less than those in literatures on PS oxidation of organic contaminants in soil by other activation methods, which can alleviate soil acidification in the remediation process. The results of this study suggest a novel technique for potential application in in-situ remediation of organic contaminated sites.
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24714. 题目: New advances in fluorescence excitation-emission matrix spectroscopy for the characterization of dissolved organic matter in drinking water treatment: A review
文章编号: N19090409
期刊: Chemical Engineering Journal
作者: Lei Li, Yang Wang, Wenjun Zhang, Shuili Yu, Xianyun Wang, Naiyun Gao
更新时间: 2019-09-04
摘要: Fluorescence technology has been increasingly applied in dissolved organic matter (DOM) characterization due to its remarkable sensitivity and selectivity. Interest in using fluorescence technology to investigate drinking water treatment with a focus on coagulation, adsorption, membrane filtration and disinfection is growing. Fluorescence excitation-emission matrix (EEM) spectroscopy, also known as three-dimensional fluorescence (3D-EEM) or fluorescence fingerprinting, is one of the most predominant approaches because of the massive amount of data, visual maps and multidimensional information it provides. Various EEM map interpretation methods have been developed. This paper reviews current predominant 3D-EEM interpretation methods (ranging from basic methods, peak picking and fluorescence regional integration (FRI) to chemometric methods) and summarizes the latest findings and problems related to practical applications. The correlations between optical and physicochemical properties, such as molecular weight and hydrophilic-hydrophobic properties, are investigated. Novel findings on drinking water trains obtained with the assistance of these interpretation methods are discussed and broadly classified as follows: a) evaluating water treatment performance, b) observing DOM behavior, c) monitoring and predicting micropollutants and disinfection byproducts (DBPs). The importance of using artificial intelligence in fluorescence technology and developing advanced real-time sensors, the weaknesses of fluorescence spectroscopy and the need for combination with other technologies (e.g., fractionation techniques) are highlighted.

24715. 题目: Surface-modified spherical lignin particles with superior Cr(VI) removal efficiency
文章编号: N19090408
期刊: Chemosphere
作者: Hyo Won Kwak, Hyunji Lee, Ki Hoon Lee
更新时间: 2019-09-04
摘要: Lignin, natural aromatic polymer derived from plant dry matter, is second abundant biopolymer. Recently, interest in applications of lignin, especially as an adsorbent material is increasing. However, the physicochemical complexity of lignin significantly reduces access to practical environmental remediation processes. Also, there is a limitation because the adsorption performance of the pristine lignin materials is not superior to that of commercial adsorbent and ion exchange resin material. In this study, spherical lignin particles with high physicochemical stability and excellent Cr(VI) adsorption capacity are prepared using a polyethylenimine (PEI) modification strategy. This modification process significantly improves the mechanical properties and water stability of lignin by complementing the instability of lignin particles. In addition, the PEI-lignin particles exhibit a superior Cr(VI) removal capability (657.9 mg/g, the highest value for a PEI-modified natural adsorbent), which is attributed to their structural stability and introduced amine functional groups. The Cr(VI) removal with PEI-lignin particles is performed via intra-particle diffusion and adsorption followed by covalent bonding combined with a reduction process. Moreover, the PEI-lignin particles exhibit excellent reusability, which sustains their high adsorption efficiency over a long and repeated adsorption period. The results herein strongly support the potential use of PEI-lignin particles as a high performance bio-sorption material for heavy metal removal and its detoxification in aqueous wastewater streams. Evidently, this lignin-based bio-sorbent manufacturing system can provide sustainable bio-resource recycling and cost efficiency.
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24716. 题目: Fast photocatalytic inactivation of Microcystis aeruginosa by metal-organic frameworks under visible light
文章编号: N19090407
期刊: Chemosphere
作者: Gongduan Fan, Jinjin Zhou, Xiaomei Zheng, Jing Luo, Liang Hong, Fangshu Qu
更新时间: 2019-09-04
摘要: In this work, Metal-organic Frameworks (MOFs) were applied to inactivate algae under visible light with low doses. Five MOFs with different compositions (Zn and Fe; carboxylates or imidazolates) were successfully synthesized and characterized by XRD, SEM and UV–vis. The effects of MOFs on Microcystis aeruginosa were evaluated with regard to morphology characteristics, physiological activity, cell integrity and pigment degradation. The results indicated that Ag/AgCl@ZIF-8 outperformed MOF-235, ZIF-8, Bi₂WO₆/MIL-100(Fe) and BiOBr/MOF-5 in the degradation of chlorophyll a at the dose of 10 mg L⁻¹. After 6 h of irradiation, 93.1% of Microcystis aeruginosa died and was unable to regrow and reproduce, which was demonstrated by changes in cell morphology, damage of cell membrane integrity and antioxidant enzyme system. Besides, the intracellular organic matter (IOM) and extracellular organic matter (EOM) were proven to be efficiently removed by MOF-assisted photocatalytic inactivation. Superoxide radical (O₂·^-) was demonstrated to be the major reactive oxygen species. A probable mechanism was proposed that the electrons in the valence band of Ag/AgCl@ZIF-8 transfer into the conduction band under irradiation to produce O₂·^- which inactivated the algae cells. Furthermore, Ag/AgCl@ZIF-8 can effectively remove Microcystis aeruginosa under sunlight and is of great application prospects for algae removal in real water bodies.
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24717. 题目: Mechanisms of U(VI) removal by biochar derived from Ficus microcarpa aerial root: A comparison between raw and modified biochar
文章编号: N19090406
期刊: Science of The Total Environment
作者: Nuo Li, Meiling Yin, Daniel C.W. Tsang, Shitong Yang, Juan Liu, Xue Li, Gang Song, Jin Wang
更新时间: 2019-09-04
摘要: Uranium (U) is a toxic and radioactive element. Excessive amounts of aqueous U(VI) generated from U mining, processing and nuclear industry may result in severe and irreversible damage to the environment. Herein, Ficus microcarpa aerial root (FMAR), a biowaste material, was used to adsorb U(VI) from aqueous solutions for the first time. Potassium permanganate (KMnO₄)-modified FMAR biochar was synthesised, characterised and compared with raw (unmodified) biochar with respect to U(VI) adsorption. The results showed that the adsorption capability of the modified FMAR biochar was evidently higher than that of the raw biochar. Multiple characterisation techniques confirmed that the discrepancy was mainly due to the increased content of O−H and formation of irregular sheet-like nanostructure with the ultrafine MnO₂ nanoparticles on the biochar surfaces after KMnO₄ modification. The abundance of O−H and nanoscale MnO₂ notably enhanced the adsorption of U(VI) by means of coordination and Lewis acid-base interaction. The results indicate that KMnO₄-modified FMAR biochar has a good potential to serve as an environment-friendly adsorbent for the removal of U(VI) from solution.
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24718. 题目: A novel enhanced anaerobic biodegradation method using biochar and Fe(OH)₃@biochar for the removal of nitrogen heterocyclic compounds from coal gasification wastewater
文章编号: N19090405
期刊: Science of The Total Environment
作者: Jingxin Shi, Hongjun Han, Chunyan Xu
更新时间: 2019-09-04
摘要: Three identical lab-scale sequencing batch reactors (SBR) were operated for 120 days for raw (R₁), biochar (R₂), and Fe(OH)₃@biochar (R₃) enhanced anaerobic degradation of selected nitrogen heterocyclic compounds (NHCs). The occurrence of Fe-OH ensured the successful attachment of Fe(OH)₃ to biochar as evidenced by the Fourier transform infrared (FTIR) spectra of biochar and Fe(OH)₃@biochar. Acute biotoxicity experiments revealed that enhancing biochar and Fe(OH)₃@biochar effectively decreased the toxicity of microorganisms. Additionally, the introduction of biochar and Fe(OH)₃@biochar improved the settling performance of anaerobic sludge. Further, it was concluded that enriched Longilinea and Comamonas might be the major genera that function to degrade selected NHCs in anaerobic conditions.
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24719. 题目: Occurrence and transport behaviors of perfluoroalkyl acids in drinking water distribution systems
文章编号: N19090404
期刊: Science of The Total Environment
作者: Ruya Chen, Guiwei Li, Ying Yu, Xu Ma, Yuan Zhuang, Hui Tao, Baoyou Shi
更新时间: 2019-09-04
摘要: Although human exposure to perfluoroalkyl acids (PFAAs) through tap water is an ongoing concern, knowledge of the PFAAs occurrence in the tap water and the associated transport behaviors of PFAAs in drinking water distribution systems (DWDSs) are scarce. This investigation profiled the occurrence of 17 kinds of PFAAs in tap water of some Chinese cities, and the transport behaviors of PFAAs in DWDS were observed in eastern China. Tap water samples both along trunk pipelines and at the distal ends were collected to display the PFAAs occurrence scenarios. Loose deposit solids were also obtained to reveal their possible accumulation effect on PFAAs. The results showed that perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) widely existed in tap water samples, and were the predominant PFAAs in eastern China areas. The mean concentration of the 17 PFAAs was 77.49 ng/L (ranging from 9.29 ng/L to 266.68 ng/L). Short-chain PFAAs (mainly PFBA) concentrations were relatively stable from water treatment plant to consumer taps, while long-chain PFAAs (mainly PFOA) exhibited a significant decrease in concentration, which could be attributed to their accumulation by the loose deposits in the DWDSs. It was calculated that PFOA has a higher partition coefficient than PFBA; this means that the former has a stronger potential to be adsorbed by loose deposits. In addition, the accumulation ability of loose deposits might be associated with the composition of Al, Fe and Si in the loose deposits. The positive correlation between the short-chain PFAAs and dissolved organic carbon (DOC) indicated the possible interactions between PFAA and natural organic matter could favor short-chain PFAAs to retain in bulk water. When water quality conditions change or hydraulic disturbance occur, loose deposits may enter tap water bringing accumulated PFAAs with it, which may result in potential health risks.
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24720. 题目: Degradation of nitrogen-containing refractory organic wastewater using a novel alternating-anode electrochemical system
文章编号: N19090403
期刊: Science of The Total Environment
作者: Yang Deng, Nan Chen, Chuanping Feng, Haishuang Wang, Yuhan Zheng, Fangxin Chen, Wang Lu, Peijing Kuang, Hanguang Feng, Yu Gao, Weiwu Hu
更新时间: 2019-09-04
摘要: This study presented a novel alternating-anode electrochemical system (AAES) based on single electrolytic cell for the treatment of nitrogen-containing refractory organic wastewater (NOW). The core of AAES lies in the alternating working of iron anode and DSA anode to integrate different electrochemical processes. The biologically treated landfill leachate (BTLL) was selected as a practical NOW for assessing the performance of AAES. The results indicated that after 140 min of electrolytic reaction, the removal efficiency of chemical oxygen demand and total nitrogen (TN) using AAES was found to be 76.9 and 98.9%, respectively. The main component of dissolved organic matter (DOM) in BTLL included humic-like substances, which could be degraded into small-molecule DOM, such as fulvic-like substances and protein-like substances, by available chlorine and hydroxyl radicals present in AAES. Cathode reduction (NO_x⁻-N → NH₄⁺–N and N₂) under iron anode and indirect oxidation (NH₄⁺–N → N₂) under DSA anode were the main pathways to remove TN from NOW. Owing to the redox conditions created by the alternating anodes, the main stable crystalline forms of precipitates obtained from AAES were Fe₃O₄ and γ-Fe₂O₃, which could be separated by using the external magnetic field. The findings of this study may provide a feasible solution for the advanced electrochemical treatment of NOW in a single electrolytic cell as well as rapid separation of precipitates.
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