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25241. 题目: The potential role of sediment organic phosphorus in algal growth in a low nutrient lake
文章编号: N19092609
期刊: Environmental Pollution
作者: Zhaokui Ni, Shengrui Wang, Jingjing Cai, Hong Li, Alan Jenkins, Stephen C. Maberly, Linda May
更新时间: 2019-09-26
摘要: The role of sediment–bound organic phosphorus (P_o) as an additional nutrient source is a component of internal P budgets in lake system that is usually neglected. Here we examined the relative importance of sediment P_o to internal P load and the role of bioavailable P_o in algal growth in Lake Erhai, China. Lake Erhai sediment extractable P_o accounted for 11–43% (27% average) of extractable total P, and bioavailable P_o accounted for 21–66% (40%) of P_o. The massive storage of bioavailable P_o represents an important form of available P, essential to internal loads. The bioavailable P_o includes mainnly labile monoester P and diester P was identified in the sequential extractions by H₂O, NaHCO₃, NaOH, and HCl. 40% of H₂O−P_o, 39% of NaHCO₃−P_o, 43% of NaOH−P_o, and 56% of HCl−P_o can be hydrolyzed to labile monoester and diester P, suggesting that the bioavailability of P_o fractions was in decreasing order as follows: HCl−P_o > NaOH−P_o > H₂O−P_o > NaHCO₃−P_o. It is implied that traditional sequential fractionation of P_o might overestimate the availability of labile P_o in sediments. Furthermore, analysis of the environmental processes of bioavailable P_o showed that the stabler structure of dissloved organic matter (DOM) alleviated the degradation and release of diester P, abundant alkaline phosphatase due to higher algal biomass promoted the degradation of diester P. The stability of DOM structure and the degradation of diester P might responsible for the spatial differences of labile monoester P. The biogeochemical cycle of bioavailable P_o replenishs available P pools in overlying water and further facilitate algal growth during the algal blooms. Therefore, to control the algal blooms in Lake Erhai, an effective action is urgently required to reduce the accumulation of P_o in sediments and interrupt the supply cycle of bioavailable P_o to algal growth.
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25242. 题目: Electrochemical Characterization of Natural Organic Matter by Direct Voltammetry in an Aprotic Solvent
文章编号: N19092608
期刊: Environmental Science: Processes Impacts
作者: Ania S. Pavitt, Paul G Tratnyek
更新时间: 2019-09-26
摘要: The complex and indeterminant composition of NOM makes characterization of its redox properties challenging. Approaches that have been taken to address this challenge include chemical probe reactions, potentiometric titrations, chronocoulometry, and voltammetry. In this study, we revisit the use of direct voltammetric methods in aprotic solvents by applying an expanded and refined suite of methods to a large set of NOM samples and model compounds (54 NOM samples from 10 different sources, 7 NOM model compounds, and 2 fresh extracts of plant materials that are high in redox-active quinonoid model compounds dissolved in DMSO). Refinements in the methods of fitting the data obtained by staircase cyclic voltammetry (SCV) provided improved definition of peaks, and square wave voltammetry (SWV), performed under the same conditions as SCV, provided even more reliable identification and quantitation of peaks. Further evidence is provided that DMSO improves the electrode response by unfolding some of the tertiary structure of NOM polymers, thereby allowing greater contact between redox active functional groups and the electrode surface. We averaged experimental peak potentials for all NOM compounds and calculated potentials in water. Average values for Epa1, Epc1, and Ep1 in DMSO were −0.866±0.069, −1.35±0.071, and −0.831± 0.051 V vs Ag/Ag+, and -0.128, -0.613, and -0.0930 V vs SHE in water. In addition to peak potentials, the breadth of SCV peaks was quantified as a way to characterize the degree to which the redox activity of NOM is due to a continuum of contributing functional groups. The average breadth values were 1.63±0.24, 1.28±0.34, and 0.648±0.15 V for Epa1, Epc1, and Ep1 respectively. Comparative analysis of the overall dataset—from SCV and SWV on all NOMs and model compounds—revealed that NOM redox properties vary over a narrower range than expected based on model compound properties. This lack of diversity in redox properties of NOM is similar to conclusions from other recent work on the molecular structure of NOM, all of which could be the result of selectivity in the common extraction methods used to obtain the materials.

25243. 题目: Activated carbon biochar from municipal waste as a sorptive agent for the removal of polyaromatic hydrocarbons (PAHs), phenols and petroleum based compounds in contaminated liquids
文章编号: N19092607
期刊: Journal of Environmental Management
作者: G.L. Sullivan, R.M. Prigmore, P. Knight, A.R. Godfrey
更新时间: 2019-09-26
摘要: Wastewater (WW) sludge cake is problematic to dispose of with treatment unable to remove organic pollutants. Typical disposal options include landfill or deposition on agricultural land, at considerable expense and environmental impact. Pyrolysis can recycle this waste to biochar however, additional unwanted organic pollutants are generated, differing in composition and volume according to the feedstock. These pollutants can be captured in solvent impingers or ‘scrubbers’ to avoid environmental release but lead to alternative waste. Both activated carbon and biochar are proven clean-up methods for organic pollutants with pine wood biochar showing changes in extraction selectivity with preparation temperature. Activated carbon biochar (ACB) from pine wood has also been successfully compared as a substitute at reduced cost and improved efficacy. To our knowledge, ACB from sludge cake has remained untested along with its application to clean-up solvent scrubbers. We have investigated this material from two WW treatment plants (UK and Ghana) as a sorbent, generated at 400 and 700 °C, to minimise contamination of liquids from pyrolysis and, petrochemicals in the event of a spill. This study confirmed the use and selective production of ACB for preferential clean-up of specific pollutants. Despite high temperature pine wood ACB proving most effective in removing petrochemical mixtures (>76%) extractions of equivalent repeatability and reasonable recovery were achieved with low temperature sludge cake ACB. This re-use of waste sludge cake offers improved thermochemical (recycling) and WW process efficiency, limiting the environmental impact and overall operational costs, minimising waste for disposal.

25244. 题目: Microwave-assisted production of CO₂-activated biochar from sugarcane bagasse for electrochemical desalination
文章编号: N19092606
期刊: Journal of Hazardous Materials
作者: Yi-Hsin Tang, Shou-Heng Liu, Daniel C.W. Tsang
更新时间: 2019-09-26
摘要: A high-performance carbon electrode is desirable for promoting electrochemical desalination efficiency in the membrane capacitive deionization (MCDI). Sugarcane bagasse (food waste) was employed in this study to prepare hierarchically porous biochars by microwave-assisted carbonization and activation with potassium hydroxide in N₂ or CO₂ atmosphere under varying flow rates (100-600 cm³ min⁻¹). The sugarcane bagasse-derived biochars activated under CO₂ flow of 300 cm³ min⁻¹ (denoted as SBB-CO₂-300) possessed the ratio of mesopores to total pore volume (V_meso/V_total) of 56.7% with a specific surface area of 1019 m² g⁻¹. The electrochemical behavior of SBB-CO₂-300 was demonstrated by a surpassing specific capacitance of 208 F g⁻¹ at 5 mV s⁻¹ by means of cyclic voltammetry. The desalination tests using a batch-mode MCDI at 1.2 V in a 5 mM NaCl solution indicated that the SBB-CO₂-300 electrode exhibited an excellent electrosorption capacity of 28.9 mg g^-1. The improvement in the electrochemical deionization performance of SBB-CO₂-300 was attributed to the superior V_meso/V_total ratio, high surface area, excellent capacitance behavior, and hierarchical pore structure. The biowaste-derived biochars prepared via facile microwave-assisted carbonization and CO₂ activation route can provide a sustainable and high-efficiency carbon electrode for electrochemical deionization of brackish water.

25245. 题目: Adsorption of copper(II) and lead(II) from seawater using hydrothermal biochar derived from Enteromorpha
文章编号: N19092605
期刊: Marine Pollution Bulletin
作者: Wenchao Yang, Zhaowei Wang, Shuang Song, Jianbo Han, Hong Chen, Xiaomeng Wang, Ruijun Sun, Jiayi Cheng
更新时间: 2019-09-26
摘要: The objective of this research was to evaluate the capacity of Enteromorpha derived biochar to adsorb heavy metals from seawater. The biochar characteristics were determined, and isothermal and kinetic data were obtained using batch experiments. Copper [Cu(II)] and lead [Pb(II)] adsorption by the biochar was favored by high pH conditions, while elevated salinity had a relatively weak negative effect on adsorption. The Langmuir isotherm and adsorption kinetics pattern enabled interpretation of the equilibrium and kinetics of Cu(II) and Pb(II) removal by the biochar. The maximum removal rates of Cu(II) and Pb(II) by the biochar in 60 min were estimated to be 91% and 54%, respectively. A model describing the adsorption processes was developed to predict the efficiency of heavy metal removal by the biochar. The outcomes of the present study indicate that Enteromorpha derived biochar could be an effective and environmentally friendly adsorbent for removing heavy metals from marine environments.

25246. 题目: Structural variation of coloured dissolved organic matter during summer and winter seasons in a tropical estuary: A case study
文章编号: N19092604
期刊: Marine Pollution Bulletin
作者: N.V.H.K. Chari, Sudarsana Rao Pandi, Vishnu Vardhan Kanuri, Charan Kumar Basuri
更新时间: 2019-09-26
摘要: The diurnal variations in water quality and optical properties of organic matter were studied in the Gautami-Godavari estuary during two contrasting seasons. Dissolved inorganic nitrogen (DIN) and silicate showed similar patterns with the tide during summer, whereas in winter contrasting trends were noticed. Three-folds higher N to P ratio was recorded in winter than in summer. The spectral slope ratio (S_R) and specific ultra violet absorption coefficient (SUVA) peaked during summer (1.28 ± 0.09 and 3.95 ± 0.2) followed by winter (1.10 ± 0.18 and 1.91 ± 0.35). The parallel factor (PARAFAC) analysis of excitation emission matrix (EEM) fluorescence spectra was extracted three humic (C1, C2, C3) and one protein-like (tryptophan (C4)) fluorophore components. Humic like fluorophores inversely correlated with the tide in both the seasons, due to influence of seawater. In summer, the Chlorophyll a (Chl a) and dissolved organic carbon (DOC) showed positive correlations with humic like and C4 fluorophores, suggesting the insitu organic matter production.

25247. 题目: Changes in mangrove community structures affecting sediment carbon content in Yingluo Bay of South China
文章编号: N19092603
期刊: Marine Pollution Bulletin
作者: Gang Wang, Dongsheng Guan, Ling Xiao, M.R. Peart, Hui Zhang, Minerva Singh
更新时间: 2019-09-26
摘要: This study aimed to assess how sediment organic carbon (SOC) dynamics were affected by mangrove community structures. Sediment attributes and community structures of the Avicennia marina, Aegiceras corniculatum, Rhizophora stylosa, and Bruguiera gymnorrhiza communities were analyzed, based upon field investigation in Yingluo Bay of South China. Aboveground biomass (AGB), belowground biomass (BGB) and tree height obviously increased with the self-thinning process, while basal area significantly decreased. The self-thinning exponent was 1.382 for AGB and 1.254 for BGB, conforming to the 4/3 self-thinning rule. However, self-thinning exponent for basal area was only 0.4866. SOC content non-linearly increased with the increase of AGB, BGB, and tree height. Mangrove-derived carbon increased through in situ organic material inputs with mangrove growth. The negative correlation between tree density and SOC content was not in line with the previous studies for planted mangroves. SOC dynamics of natural mangroves may be partially different from planted mangroves.

25248. 题目: The role of grain size and inoculum amount on biocrust formation by Leptolyngbya ohadii
文章编号: N19092602
期刊: CATENA
作者: Gianmarco Mugnai, Federico Rossi, Sonia Chamizo, Alessandra Adessi, Roberto De Philippis
更新时间: 2019-09-26
摘要: Cyanobacteria are widespread prokaryotic organisms that represent feasible biotechnological tools to set up valid approaches to counteract desertification. Their peculiar physiological traits, and their resilience to abiotic stresses, allow their application on abiotically constrained soils to trigger their stabilization. A successful cyanobacteria inoculation results in the formation of cyanobacterial biocrusts, complex microbial communities characterized by tangled filament meshes imbued in a matrix of self-secreted extracellular polysaccharides (EPS) that keep loose sediments and aggregates firmly in place. However, the capability to form stable cyanobacterial biocrusts is not common to all the species, and a mix of factors can hamper the process, notably inoculum amount, and substrate characteristics.The aim of this work was to assess the influence of inoculum quantity and substrate granulometry on the physical stability of cyanobacterial biocrusts induced by inoculating the strain Leptolyngbya ohadii in a microcosm experiment, under laboratory conditions. After applying three different initial inoculum amounts on two different sand granulometries (medium and coarse sand), we assayed aggregate stability, physical stability and surface hydrophobicity on the resulting biocrusts during a 30-day incubation. Also, the features and the role of the EPS synthesized by L. ohadii were studied following their isolation, characterization, and direct application on the sand. The two EPS fractions produced by the strain, one more soluble and easily released in the surrounding medium (released polysaccharides, RPS) and one solidly attached to the filaments (glycocalyx EPS, G-EPS), were separately tested.Cyanobacterial biocrusts visibly formed in all the microcosms after 15 days. However, we observed a strong effect of sand granulometry in affecting aggregate stability and tensile strength, both of which appeared weaker on coarse sand. A higher amount of initial inoculum was necessary to produce stable biocrusts on coarse sand compared to medium sand. Also, we observed how the inoculation of EPS alone did not sort most of the significant effects that we detected by inoculating the whole culture, pointing at the importance of the action of the cyanobacterial filaments in soil conglomeration. However, a significant increase in physical stability was achieved by inoculating G-EPS on medium sand, suggesting the involvement of this fraction in biocrusts structuration.This work analyzes for the first time the effects of the variable grain size and inoculum amount in the achievement of physically stable biocrusts by cyanobacteria inoculation. The results that we obtained are useful in improving and optimizing the process of biomass preparation and dispersion for future indoor and outdoor studies.

25249. 题目: Investigation of the sorption of 17α-ethynylestradiol (EE2) on soils formed under aerobic and anaerobic conditions
文章编号: N19092601
期刊: Chemosphere
作者: Lili Szabó, Anna Vancsik, Csilla Király, Marianna Ringer, Attila Kondor, Gergely Jakab, Zoltán Szalai, Tibor Filep
更新时间: 2019-09-26
摘要: A study was conducted on the sorption of 17α-ethynylestradiol (EE2) on five soils formed under different redox conditions: an Arenosol (A_20) with fully aerobic conditions, two Gleysol samples (G_20 and G_40) with suboxic and anoxic conditions and two Histosols (H_20 and H_80) with mostly anoxic conditions. The soils were characterized on the basis of total organic carbon (TOC), specific surface area (SSA) and the Fourier transform infrared spectra of the humic acid and humin fractions (the soil remaining after alkali extraction) of the soil. The maximum adsorption capacity of the soils (Q_max) ranged from 10.7 to 83.6 mg/g in the order G_20 > H_20 > G_40 > A_20 > H_80, which reflected the organic matter content of the soils. The sorption isotherms were found to be nonlinear for all the soil samples, with Freundlich n values of 0.45–0.68. The strong nonlinearity found in the adsorption of the H_80 samples could be attributed to their high hard carbon content, which was confirmed by the high aromaticity of the humin fraction. The maximum sorption capacity (Q_max) of the soils did not increase indefinitely as the organic carbon content of the soils rose. There could be two reasons for this: (i) the large amount of organic matter may reduce the number of binding sites on the surface, and (ii) the decrease in SSA with increasing soil OC content may limit the ability to adsorb EE2 molecules. In anaerobic soil samples, where organic matter accumulation is pronounced, the amount of aromatic and phenolic compounds was higher than in better aerated soil profiles. Strong correlations were found between the amount of aromatic and phenolic compounds in the organic matter and the adsorption of EE2 molecules, indicating that π-π interaction and H-bonding are the dominant sorption mechanisms.
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25250. 题目: Efficient removal of arsenic from groundwater using iron oxide nanoneedle array-decorated biochar fibers with high Fe utilization and fast adsorption kinetics
文章编号: N19092503
期刊: Water Research
作者: Yuanfeng Wei, Shudan Wei, Chengbin Liu, Tao Chen, Yanhong Tang, Jianhong Ma, Kai Yin, Shenglian Luo
更新时间: 2019-09-25
摘要: Although Fe-based biochar adsorbents are attractive for removing arsenic from water due to their advantages of costing little and being producible at a large scale, the practical applications of these granular adsorbents are mainly limited by low Fe utilization and slow adsorption kinetics. In this study, iron oxide nanoneedle array-decorated biochar fibers (Fe-NN/BFs) adsorbents have been prepared through a simple hydrothermal reaction. The vertical growth of iron oxide nanoneedle arrays on the surface of biochar fibers maximizes Fe utilization and shortens As diffusion distance, thereby increasing As removal kinetics and capacity. Batch experiments show that the adsorption capacities of Fe-NN/BFs for As(V) and As(III) reach to 93.94 and 70.22 mg/g-Fe at pH 7.0, respectively. As(V) levels (275 μg/L) in groundwater are rapidly reduced (less than 5 min) to below 10 μg/L using Fe-NN/BFs (1 g/L) at pH 6.7. Similar As(III) levels can be reduced to below 10 μg/L within 30 min by Fe-NN/BFs (1.5 g/L). In fixed-bed experiments, the treatment volumes of As(V) and As(III) spiked groundwater reach to 2900 BV (26.2 L) and 2500 BV (22.6 L), respectively, using two columns packed with Fe-NN/BFs in tandem (C₀ = 275 μg/L, 2 g of adsorbents in each column). When the As concentration in the influent is reduced to 50 μg/L (As(V): 25 μg/L + As(III): 25 μg/L), the treatment volume using one column reaches up to 11000 BV. The Fe-NN/BFs packed column can be easily regenerated and reused many times. After four regenerations, the treatment volume of As(V) and As(III) were reduced by 10.4% and 22.8%, respectively.
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25251. 题目: Total and active soil fungal community profiles were significantly altered by six years of warming but not by grazing
文章编号: N19092502
期刊: Soil Biology and Biochemistry
作者: Rongxiao Che, Shiping Wang, Yanfen Wang, Zhihong Xu, Weijin Wang, Yichao Rui, Fang Wang, Jinming Hu, Juan Tao, Xiaoyong Cui
更新时间: 2019-09-25
摘要: We examined the responses of total and active soil fungal communities to experimental warming, moderate grazing, and their combination. The six years of field experiments were established in a Tibetan alpine meadow. An infrared heating system was used to simulate warming, and the grazing was conducted by a combination of sheep grazing and clipping. Total and active soil fungal community profiles were determined using MiSeq sequencing of internal transcribed spacer (ITS) DNA and RNA, respectively. Fungal abundance and rDNA transcriptional activity were analyzed through real-time PCR. The results showed that the warming significantly changed the community structures of soil fungi, particularly the active populations. Specific changes in fungal community profiles under the warming scenario included an increase in the proportion of Dothideomycetes (a potential oligotrophic class) and a decrease in the proportion of active plant-symbiotic lineages (e.g., Glomerales). FUNGuild-based functional predictions suggested that warming significantly reduced the proportions of arbuscular mycorrhizal and active saprotrophic fungi. We compared our results to those of another investigation performed at the same location, and found that the ITS-FUNGuild approach was even more sensitive than the 18S rDNA-based method with respect to identifying arbuscular mycorrhizal fungal taxa. Additionally, the warming attenuated the interactions among fungal species, reduced the Chao 1 index of active fungal communities, increased the active fungal community dispersion, and tended to suppress the transcription of fungal rDNA. In contrast, no significant effects of grazing and warming-grazing interactions on soil fungal communities were observed. These findings indicate that global warming may weaken the capacity of soil fungi to decompose organic matter and to facilitate plant nutrient absorption, whereas fungi in Tibetan alpine meadow soils are insensitive to moderate grazing.

25252. 题目: Microstructure and composition of marine aggregates as co-determinants for vertical particulate organic carbon transfer in the global ocean
文章编号: N19092501
期刊: Biogeosciences
作者: Joeran Maerz, Katharina D. Six, Irene Stemmler, Soeren Ahmerkamp, and Tatiana Ilyina
更新时间: 2019-09-25
摘要: Marine aggregates are the vector for biogenically bound carbon and nutrients from the euphotic zone to the interior of the oceans. To improve the representation of this biological carbon pump in the global biogeochemical HAMburg Ocean Carbon Cycle (HAMOCC) model, we implemented a novel Microstructure, Multiscale, Mechanistic, Marine Aggregates in the Global Ocean (M⁴AGO) sinking scheme. M⁴AGO explicitly represents the size, microstructure, heterogeneous composition, density, and porosity of aggregates, and ties ballasting mineral and particulate organic carbon (POC) fluxes together. Additionally, we incorporated temperature-dependent remineralization of POC. We compare M⁴AGO with the standard HAMOCC version, where POC fluxes follow a Martin curve approach with linearly increasing sinking velocity with depth, and temperature-independent remineralization. Minerals descend separately with a constant speed. In contrast to the standard HAMOCC, M⁴AGO reproduces the latitudinal pattern of POC transfer efficiency which has been recently constrained by Weber et al. (2016). High latitudes show transfer efficiencies of ≈ 0.25 ± 0.04 and the subtropical gyres show lower values of about 0.10 ± 0.03. In addition to temperature as a driving factor, diatom frustule size co-determines POC fluxes in silicifiers-dominated ocean regions while calcium carbonate enhances the aggregate excess density, and thus sinking velocity in subtropical gyres. In ocean standalone runs and rising carbon dioxide (CO₂) without CO₂ climate feedback, M⁴AGO alters the regional ocean-atmosphere CO₂ fluxes compared to the standard model. M⁴AGO exhibits higher CO₂ uptake in the Southern Ocean compared to the standard run while in subtropical gyres, less CO₂ is taken up. Overall, the global oceanic CO₂ uptake remains the same. With the explicit representation of measurable aggregate properties, M⁴AGO can serve as a testbed for evaluating the impact of aggregate-associated processes on global biogeochemical cycles, and, in particular, on the biological carbon pump.

25253. 题目: Volatile methanol and acetone additions increase labile soil carbon and inhibit nitrification
文章编号: N19092404
期刊: Biogeochemistry
作者: Steven G. McBride, Ernest D. Osburn, John E. Barrett, Michael S. Strickland
更新时间: 2019-09-24
摘要: Recent efforts to understand the contribution of low-molecular weight compounds to carbon dynamics in soil ecosystems has resulted in a framework that suggests that low-molecular weight, labile carbon compounds can be directly assimilated by microbial biomass before being stabilized on soil colloids. However, this model primarily focuses on dissolved organic matter inputs and overlooks the potential importance of volatile organic compounds (VOCs). Here we determined the effects of two VOCs commonly emitted from soil and decomposing leaf litter (methanol, and acetone) on soil respiratory dynamics during a 28-day lab experiment. At the end of the experiment we quantified carbon and nitrogen concentrations in dissolved organic matter, microbial biomass, particulate organic matter, mineral associated organic matter, the labile carbon pool, and we quantified nitrifying microorganism abundance. Our results demonstrate that VOCs (i.e. methanol and acetone) increase soil respiration, contribute to labile soil C, and inhibit nitrification. Our VOC additions resulted in respiration spikes 4.1–5.5-fold greater than the control for acetone and methanol, respectively, though respiration returned back to control levels within 144 h after additions. Our VOC additions resulted in a 1.6–1.7-fold increase in labile soil carbon, suggesting that litter-derived VOCs could enter soil C pools following microbial metabolism. Additionally, soils exposed to VOCs contained ~ 2.25-fold less total dissolved nitrogen, and ~ 34–220-fold less nitrate. Ammonia oxidizing archaea were ~ 1.5 fold less abundant in VOC treated soils than in the control. After VOC additions were ceased, nitrate levels increased at approximately the same rate in all treatments, suggesting an inhibitory effect of methanol and acetone on nitrifying microorganisms. These results indicate that common decomposition derived VOCs play an important yet under-recognized role in driving the formation of soil organic matter as well as increasing the immobilization of nitrogen in soil ecosystems.

25254. 题目: A novel Biochar modified by Chitosan-Fe/S for tetracycline adsorption and studies on site energy distribution
文章编号: N19092403
期刊: Bioresource Technology
作者: Juanli Liu, Baiqin Zhou, Hong Zhang, Juan Ma, Bin Mu, Wenbo Zhang
更新时间: 2019-09-24
摘要: A novel wasted sludge-based Biochar modified by Chitosan and Fe/S (BCFe/S) was prepared for tetracycline (TC) removal from water. To investigate the similarities and differences in adsorption behaviors between Biochar and BCFe/S, characterization, kinetics, isotherms and thermodynamics were discussed. The studies on site energy distribution (SED) were also presented. The results showed that the maximum TC adsorption amount was 51.78 mg/g for Biochar, while it was 183.01 mg/g for BCFe/S-4. Meanwhile, electrostatic attraction, π-π stacking, pore filling, silicate bonding and hydrogen bonding were the main adsorption mechanisms for TC removal by Biochar. Besides above mechanisms, chelating and ion exchange were also accounted for adsorption mechanisms for TC uptake by BCFe/S-4. Moreover, SED results revealed that the surface of Biochar was more homogeneous while the surface of BCFe/S-4 was more heterogeneous at higher temperature. Findings of this work could offer valuable information in designing adsorbents and investigating adsorption mechanisms.
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25255. 题目: Seasonal organic matter dynamics in a temperate shelf sea
文章编号: N19092402
期刊: Progress in Oceanography
作者: Clare E. Davis, Sabena Blackbird, George Wolff, Malcolm Woodward, Claire Mahaffey
更新时间: 2019-09-24
摘要: Organic matter (OM) plays an important role in productive shelf seas and their contribution to global carbon (C) and nutrient cycles. We investigated dissolved and particulate OM (DOM and POM, respectively) dynamics over a seasonal cycle in the Celtic Sea. The quantity of OC was largest during the spring bloom and lowest in autumn. DOM was always C rich relative to the POM pool and the Redfield ratio (106C:16N:P). There was clear decoupling between C, N and P and the response of OM composition to different seasons and nutrient statuses of the microbial community. The C:P stoichiometry was much more variable than the C:N stoichiometry, which was near constant. Downward OC fluxes were dominated by POM during bloom events and DOM during the stratified summer. In terms of partitioning, 92–96% of OC was in the DOM pool throughout sampling, which given its high C:N (12.4–17) suggests it was an efficient vehicle for potential off-shelf export of C during winter mixing.

25256. 题目: Seasonal changes in plankton respiration and bacterial metabolism in a temperate shelf sea
文章编号: N19092401
期刊: Progress in Oceanography
作者: E. Elena García-Martín, Chris J. Daniels, Keith Davidson, Clare E. Davis, Claire Mahaffey, Kyle M.J. Mayers, Sharon McNeill, Alex J. Poulton, Duncan A. Purdie, Glen A. Tarran, Carol Robinson
更新时间: 2019-09-24
摘要: The seasonal variability of plankton metabolism indicates how much carbon is cycling within a system, as well as its capacity to store carbon or export organic matter and CO₂ to the deep ocean. Seasonal variability between November 2014, April 2015 and July 2015 in plankton respiration and bacterial (Bacteria + Archaea) metabolism is reported for the upper and bottom mixing layers at two stations in the Celtic Sea, UK. Upper mixing layer (UML, >75 m in November, 41–70 m in April and ∼50 m in July) depth-integrated plankton metabolism showed strong seasonal changes with a maximum in April for plankton respiration (1.2- to 2-fold greater compared to November and July, respectively) and in July for bacterial production (2-fold greater compared to November and April). However UML depth-integrated bacterial respiration was similar in November and April and 2-fold lower in July. The greater variability in bacterial production compared to bacterial respiration drove seasonal changes in bacterial growth efficiencies, which had maximum values of 89% in July and minimum values of 5% in November. Rates of respiration and gross primary production (¹⁴C-PP) also showed different seasonal patterns, resulting in seasonal changes in ¹⁴C-PP:CR_O2 ratios. In April, the system was net autotrophic (¹⁴C-PP:CR_O2 > 1), with a surplus of organic matter available for higher trophic levels and export, while in July balanced metabolism occurred (¹⁴C-PP:CR_O2 = 1) due to an increase in plankton respiration and a decrease in gross primary production. Comparison of the UML and bottom mixing layer indicated that plankton respiration and bacterial production were higher (between 4 and 8-fold and 4 and 7-fold, respectively) in the UML than below. However, the rates of bacterial respiration were not statistically different (p > .05) between the two mixing layers in any of the three sampled seasons. These results highlight that, contrary to previous data from shelf seas, the production of CO₂ by the plankton community in the UML, which is then available to degas to the atmosphere, is greater than the respiratory production of dissolved inorganic carbon in deeper waters, which may contribute to offshore export.

25257. 题目: Application of biochar and its composites in catalysis
文章编号: N19092304
期刊: Chemosphere
作者: Honghong Lyu, Qianru Zhang, Boxiong Shen
更新时间: 2019-09-23
摘要: With a wide range of raw materials, low cost and large specific surface area, biochar has been widely used in environmental remediation. However, the biochar has a saturated adsorption capacity when it is used as a pollutant adsorbent. Recent efforts have been made to prepare biochar and biochar-based catalysts with enhanced catalytic properties to expand their potential applications. The environmental persistent free radicals (EPFRs) of biochar could react with O₂ to induce hydroxyl radicals (•OH) without the addition of oxidants. When oxidants were added, biochar and biochar-based catalysts could activate them to generate •OH and sulfate radicals (SO4^•−), respectively. Moreover, biochar could act as an electron acceptor to improve the photodegradation capacity of catalysts. With reference to the information regarding biochar and biochar-based catalysts, this work provides a critical review on recent research development as follows: 1) the preparations of various types of biochar and biochar-based catalysts are summarized; 2) the effects of the synthetic conditions and transition metals on the catalytic activity of biochar-based catalysts are discussed; (3) methods for characterizing the active sites of the biochar-based catalysts are described; and (4) the environmental applications of biochar and biochar-based catalysts are discussed with regards to three aspects based on the interaction mechanisms, namely, oxidation, reduction, and photocatalysis. The synthesis conditions and loading of metal/metal-free catalyst are key parameters controlling the catalysis activity of biochar and biochar-based catalysts. This review provides new insights into the application of biochar in catalysis. Key challenges and further research directions are proposed as well.
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25258. 题目: Spectrum evolution of dissolved aromatic organic matters (DAOMs) during electro-peroxi-coagulation pretreatment of coking wastewater
文章编号: N19092303
期刊: Separation and Purification Technology
作者: Xin Zhou, Zilong Hou, Jingjing Song, Lin Lv
更新时间: 2019-09-23
摘要: Enormous existence of dissolved aromatic organic matters (DAOMs) is considered to be a major cause that coking wastewater is hardly degraded. In this study, an advanced electro-chemical process i.e. electro-peroxi-coagulation (EPC) was developed as a pretreatment for efficiently degrading DAOMs and improving the biodegradability of the raw coking wastewater. Gas chromatography-mass spectrometry (GC-MS) also confirmed that most of DAOMs (phenolics, heterocycles, polycyclic aromatic hydrocarbons, benzenes, organic nitriles and anilines) could be effectively decomposed by EPC pretreatment. Ultraviolet visible (UV-Vis), Fourier transform infrared spectroscopy (FTIR) and excitation-emission matrix (EEM) consistently found remarkable spectrum variations of DAOMs in the first 15 min, while spectrum changes became gentle until 2 h. The spectrum evolution of DAOMs suggests the strong attacks on the benzene rings and unsaturated bonds of DAOMs occurs initially and then low molecule intermediates are further degraded. Therefore, EPC should be a feasible option for coking wastewater pretreatment based on the combination of electro-oxidation and electro-precipitation.
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25259. 题目: Coupled retention of bovine serum albumin and NOM by porous membranes
文章编号: N19092302
期刊: Separation and Purification Technology
作者: Lanlan Qin, Haiou Huang
更新时间: 2019-09-23
摘要: Coupled retention of natural organic matter (NOM) is an important process in membrane water treatment. A mechanistic understanding is lacking due to the complex nature of NOM. In this study, filtration experiments were conducted with the mixture of bovine serum albumin (BSA) and Suwannee River NOM (SRNOM) through different pore-sized membranes. A macroscopic depth filtration theory was utilized for analyzing the underlying mechanisms. The results showed the importance of BSA-SRNOM interactions on NOM retention. At a neutral pH of 7.0, the co-existing SRNOM reduced BSA retention by up to 24% by mitigating concentration polarization and inner-pore BSA deposition. Meanwhile, the presence of BSA elevated SRNOM retention by up to 23% because of SRNOM adsorption onto the deposited BSA, as well as enhanced steric hindrance and concentration polarization effect. Furthermore, the reduction of solution pH to 3.7 enhanced BSA-SRNOM interactions that favored multilayer BSA/SRNOM deposition. As a result, BSA and SRNOM retention increased by 54% and 79 %, 78% and 37 %, and 48% and 10% for membranes having pore radii of 7.5 nm, 15 nm and 25 nm, respectively. This study demonstrated that the interplay of concentration polarization, steric hindrance, and inner-pore deposition governed NOM retention by porous membranes.

25260. 题目: Long-term stacking coal promoted soil bacterial richness associated with increased soil organic matter in coal yards of power plants
文章编号: N19092301
期刊: Journal of Soils and Sediments
作者: Congcong Shen, Dawei Ma, Ruibo Sun, Benyao Zhang, Delin Li, Yuan Ge
更新时间: 2019-09-23
摘要: Purpose: Coal exploitation inevitably brings a chain of ecological problems, e.g., land destruction and biodiversity decrease. Most previous studies have investigated the ecological effect of coal mining process and the ecological restoration after coal mining practice. However, no study has concerned about the potential influence of long-term stacking coal process on soil microbial communities, the pivotal components to maintain the health of terrestrial ecosystems. This study aims to investigate the influence of long-term stacking coal on soil microbial communities, as well as the time effect. Materials and methods: We collected soil samples from coal yards of four power plants (representing four stacking time: 10, 28, 31, and 71 years) in Huainan city. Soils in the lawn near each coal yard were also selected as control at four sites. Soil microbial communities were analyzed via 16S and 18S rRNA gene sequencing. Results and discussion: Our results showed that long-term stacking coal significantly (P < 0.05) increased soil organic matter (SOM), and thus facilitated soil bacterial richness and the shifts of bacterial community composition. We also detected significant (P < 0.05) increase of SOM, bacterial richness, and community dissimilarity with stacking time, indicating a substantial time effect. Meanwhile, predicted functional data implied that stacking coal activated anaerobic microbial communities by forming an anaerobic environment in soils. Conclusions: Together, these data provide basic knowledge of the potential influence of long-term stacking coal on soil microbial communities and reinforce the role of SOM in shaping bacterial community composition and richness.