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23361. 题目: An emerging environmental concern: Biochar-induced dust emissions and their potentially properties
文章编号: N19050303
期刊: Science of The Total Environment
作者: Danielle Leigh Gelardi, Chongyang Li, Sanjai J. Parikh
更新时间: 2019-05-03
摘要: Amending soils with biochar is increasingly proposed as a solution to many pressing agricultural and environmental challenges. Biochar, created by thermochemical conversion of biomass in an oxygen-limited environment, has several purported benefits, including remediation of contaminated soils, increased crop yields, reduced fertilizer demands, increased plant available water, and mitigation of climate change. Due to these potential benefits, biochar-related research has flourished in the past decade, though there remains a critically understudied area of research regarding biochar's potential impact on human health. Because biochar characteristically has low bulk density and high porosity, the material is susceptible to atmospheric release via natural or mechanical soil disturbance. The specific risks of biochar inhalation have not been elucidated; however, recent publications have demonstrated that biochar can increase soil dust emissions of particles <10 μm (PM10) or possess elevated levels of toxic chemicals. These data should not be interpreted to suggest that all biochars are problematic, but rather to highlight an important and overlooked field of study, and to stress the need to critically assess parameters for biochar production and management strategies that safeguard human health. Here the literature on biochar-related dust emissions and potentially toxic properties (PTPs) is reviewed in order to summarize what is known, highlight areas for future study, and aggregate solutions to minimize potential harm.
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23362. 题目: Nagasaki sediments reveal that long-term fate of plutonium is controlled by select organic matter moieties
文章编号: N19050302
期刊: Science of The Total Environment
作者: Peng Lin, Chen Xu, Daniel I. Kaplan, Hongmei Chen, Chris M. Yeager, Wei Xing, Luni Sun, Kathleen A. Schwehr, Hideo Yamazaki, Yoko Saito-Kokubu, Patrick G. Hatcher, Peter H. Santschi
更新时间: 2019-05-03
摘要: Forecasting the long-term fate of plutonium (Pu) is becoming increasingly important as more worldwide military and nuclear-power waste is being generated. Nagasaki sediments containing bomb-derived Pu that was deposited in 1945 provided a unique opportunity to explore the long-term geochemical behavior of Pu. Through a combination of selective extractions and molecular characterization via electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS), we determined that 55 ± 3% of the bomb-derived 239,240Pu was preferentially associated with more persistent organic matter compounds in Nagasaki sediments, particularly those natural organic matter (NOM) stabilized by Fe oxides (NOMFe-oxide). Other organic matter compounds served as a secondary sink of these bomb-derived 239,240Pu (31 ± 2% on average), and <20% of the 239,240Pu was immobilized by inorganic mineral particles. In a narrow, 239,240Pu-enriched layer of only 9-cm depth (total core depth was 600 cm), N-containing carboxyl aliphatic and/or alicyclic molecules (CCAM) in NOMFe-oxide and other NOM fractions immobilized the majority of 239,240Pu. Among the cluster of N-containing CCAM moieties, hydroxamate siderophores, the strongest known Pu chelators in nature, were further detected in these “aged” Nagasaki bomb residue-containing sediments. While present long-term disposal and environmental remediation modeling assume that solubility limits and sorption to mineral surfaces control Pu subsurface mobility, our observations suggest that NOM, which is present in essentially all subsurface systems, undoubtedly plays an important role in sequestrering Pu. Ignoring the role of NOM in controlling Pu fate and transport is not justified in most environmental systems.
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23363. 题目: Microbial mechanisms of the contrast residue decomposition and priming effect in soils with different organic and chemical fertilization histories
文章编号: N19050301
期刊: Soil Biology and Biochemistry
作者: Fenliang Fan, Bing Yu, Boren Wang, Timothy S. George, Huaqun Yin, Dongchu Li, Alin Song
更新时间: 2019-05-03
摘要: We integrated chemical, enzymatic, isotopic and molecular approaches to investigate both straw decomposition and its priming effect (PE) on native soil organic carbon (SOC) decomposition in soils with 23 years of application of chemical fertilizer (NPK) and partial substitution of chemical fertilizer by organic manure (NPKM). We found that NPK and NPKM past application significantly increased decomposition of straw. The increases in straw decomposition were not correlated with the abundances of microbiome assimilating straw carbon, but were significantly correlated with abundances of total bacteria, fungi and activities of cellulose-degrading enzymes. In addition, application of NPK did not change straw-induced PE while application of NPKM markedly reduced PE. The variation of PE with different past fertilization was correlated with the abundance of residue-stimulated fungi. The unchanged PE with NPK application in the presence of enriched nutrients and reduced pH was probably due to residue-promoted growth of acid-tolerant SOC-decomposing taxa (unclassified bacteria families belong to Acidobacteria GP3, Gamaproteobacteria and WPS-2 and unclassified fungal families belong to Chaetothyriales and Agaricomycetes). Our research sheds light on the complex processes of carbon transformation in the soils undergoing different long-term nutrient management.
23364. 题目: Variations in soil and plant-microbiome composition with different quality irrigation waters and biochar supplementation
文章编号: N19050211
期刊: Applied Soil Ecology
作者: Erping Cui, Xiangyang Fan, Zhongyang Li, Yuan Liu, Andrew L. Neal, Chao Hu, Feng Gao
更新时间: 2019-05-02
摘要: To reduce water scarcity in China, the use of reclaimed water or anaerobically treated piggery wastewater, either alone or coupled with biochar supplementation, is attracting increasing attention. However, little information is available regarding their effects on the soil and plant microbiomes receiving irrigation. The objective of this study was to evaluate different water quality irrigation (distilled water, reclaimed water, and piggery wastewater), biochar supplementation, and their interactions on the microbiomes of rhizosphere and bulk soil, and the root endosphere of maize using high-throughput 16S rRNA amplicon sequencing. The experiments were conducted in greenhouse rhizoboxes. The microbiome functional potentials were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). After a 60-day cultivation period, the bacterial communities and potential functions of rhizosphere, bulk soil, and root endosphere displayed distinct differences between irrigation water sources. Irrigation water quality and biochar supplementation influenced bacterial diversity in rhizosphere soil, and bacterial composition was more sensitive to irrigation water quality than to biochar supplementation in soil and root samples. Reclaimed water and piggery wastewater irrigation decreased the abundance of putative plant growth-promoting rhizobacteria (PGPR) and increased the abundance of known pathogenic bacteria. Biochar supplementation elicited the same behaviour. Mantel tests indicated that soil pH and available P exerted strong influences on the structure of the bacterial community in rhizosphere and bulk soil, but total N significantly influenced the bacterial community structure within the root. The current study implies the potential ecological effects (e.g. PGPR and pathogenic bacteria) of the irrigation with different quality water should be considered with biochar supplementation.
23365. 题目: Short-term dynamics of soil organic matter fractions and microbial activity in smallholder potato-legume intercropping systems
文章编号: N19050210
期刊: Applied Soil Ecology
作者: Shadrack O. Nyawade, Nancy N. Karanja, Charles K.K. Gachene, Harun I. Gitari, Elmar Schulte-Geldermann, Monica L. Parker
更新时间: 2019-05-02
摘要: Continuous cultivation of potato (Solanum tuberosum L.) in monoculture systems represents the greatest factor deteriorating soil organic matter (SOM) in smallholder farms. With an aim to breaking this norm, a 2-year field trial intercropping potato with two legumes: lima bean (Phaseolus lunatus) and dolichos (Lablab purpureus), was conducted in the upper-midland (1552 meters above sea level (masl.)), lower-highland (1854 masl.) and upper-highland (2552 masl.) agro-ecologies of Kenya. Residues from each cropping system were quantified at the end of each season and incorporated back into the soil at start of the subsequent season. A combined physical and density fractionation was used to separate the soil in macro-aggregates (>250 μm), micro-aggregates (250–50 μm) and silt plus clay fractions (<50 μm), while SOM was partitioned into labile (density of 1.65 to 1.85 g cm−3) and stable (2.60 g cm−3) fractions. Microbial biomass contents were determined by chloroform fumigation while enzymatic activities were assessed by hydrolyses of fluorescein diacetate and dehydrogenase. Compared to sole potato, intercropping increased the contents of light fraction organic matter by 12–28%, dissolved organic matter by 7–21% and microbial biomass by 15–38%, thus stimulating enzyme activities. Trends in soil microbial respiration followed those of enzyme activity and were 20–34% higher in intercropping than in sole potato. Intercropping ensured high residue returns which got short-term residence within the macro-aggregates, thus ensuring steady supply of substrates to the soil microbes. These results affirm legume intercropping as a possible entry point to restoring the impoverished soil quality in smallholder potato farming systems.
23366. 题目: Iron and carbon granules added to anode enhanced the sludge decrement and electrical performance of sludge microbial fuel cell
文章编号: N19050209
期刊: Chemical Engineering Journal
作者: Lu Cai, Hanmin Zhang, Yujie Feng, Bin Dong, Yuezhu Wang, Chengcheng Ge
更新时间: 2019-05-02
摘要: Sludge microbial fuel cell (SMFC) can utilize the organics in sludge to generate power, and has attracted widespread attention. However, the low efficiency of organics utilization and limited power-output are the main challenges that need to be addressed. This study proposed an in situ method without additional energy to enhance the performance of SMFC by adding the package of iron and carbon granules (FeC). In the reactors including FeC-SMFC (the FeC package placed under the carbon felt anode and separated from the closed-circuit), FeC-OSMFC (FeC-SMFC in open-circuit), and FeCSMFC (the FeC package attached to the anodic bottom and closed-circuit), the degradation of refractory organics especially humic acid-like substances was significantly promoted, due to the FeC micro-electrolysis at neutral pH. More organics were beneficial for the enrichment of typical exoelectrogens belonging to Proteobacteria and Firmicutes, thereby improving the electrical performance of FeC-SMFC and FeCSMFC, compared with normal SMFC without FeC package (NSMFC). In FeCSMFC, the soluble and total chemical oxygen demand removal efficiencies were 65.60% and 52.64%. The removal efficiency of volatile suspended solids in FeCSMFC was 69.26%, which was 30.05%, 14.97%, 9.87% and 6.62% higher than that in open-circuit SMFC, NSMFC, FeC-OSMFC and FeC-SMFC, respectively. The power output of FeCSMFC was 37.28 W m−3, 6.06 and 1.76 times higher than that of NSMFC and FeC-SMFC, respectively. The addition of FeC package to anode is a cost-saving and effective method to enhance electricity generation and sludge decrement of SMFC.
23367. 题目: Impact of background water quality on disinfection performance and silver release of immobilized silver nanoparticles: Modeling disinfection kinetics, bactericidal mechanism and aggregation behavior
文章编号: N19050208
期刊: Chemical Engineering Journal
作者: Shekhar Agnihotri, Soumyo Mukherji, Suparna Mukherji
更新时间: 2019-05-02
摘要: An aminosilane-based surface functionalization strategy was adopted to immobilize silver nanoparticles (AgNPs) on to silica materials to minimize leaching of silver into the aqueous environment. The disinfection potential and silver release of immobilized-AgNPs and chloridized silver surfaces were investigated for simulated lake water under varying water chemistry conditions. While the presence of both hardness and natural organic matter (NOM) adversely affected the disinfection kinetics and silver release from immobilized-AgNPs, alkalinity had only minor impact on disinfection performance over the concentration range 30–600 mg L−1. The higher disinfection efficacy of immobilized-AgNPs was ascribed to their contact-killing mechanism of action. In contrast, chloridized Ag that caused disinfection through the release of silver ions showed lower disinfection efficacy. Divalent cations and NOM greatly influenced the surface characteristics and morphology of the immobilized-AgNPs. However, immobilized AgNPs were more shielded than colloidal AgNPs when exposed to similar harsh conditions characterized by high hardness and NOM concentration. Under all the tested conditions, where 100% disinfection was achieved, the amount of silver release from immobilized AgNPs was less than 22 µg L−1, which is well below the USEPA permissible limit. The disinfection kinetics of immobilized-AgNPs was best fitted by the Hom model (R2 = 0.974), where its lumped parameters kh and m were found to vary with variation in background water quality. Sensitivity analyses indicated that for ‘m’ value higher than 1.9, complete disinfection could not be achieved regardless of many fold increase in ‘kh’ value.
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23368. 题目: Gaining deeper insights into the bioflocculation process occurring in a high loaded membrane bioreactor used for treatment of synthetic greywater
文章编号: N19050207
期刊: Chemosphere
作者: Seyed Aryan Emaminejad, Shirin Saffar Avval, Babak Bonakdarpour
更新时间: 2019-05-02
摘要: In the present study, a high loaded membrane bioreactor (HL-MBR) operated at an HRT of 1.5 h, and three different SRTs in the range of 0.5–2 days, was used for the treatment of synthetic greywater. The COD removal efficiency of the system was in the range 87–89% at all SRTs. Bioflocculation efficiency (defined as the percentage of suspended COD in the concentrate stream), COD bio-oxidation, total extracellular polymeric substances (EPS), tightly bound (TB) EPS and the ratio of EPS protein (EPSp) to carbohydrate (EPSc) increased when SRT was increased from 0.5 to 2 days. Sludge supernatant soluble microbial products (SMP) increased with increase in SRT from 0.5 to 2 days, while the effluent SMP was negligible. Particle size distribution analyses revealed a bimodal distribution at an SRT of 0.5 days, and normal distributions at other SRTs. Furthermore, depending on the value of the F/M ratio, different SRTs in the range of 0.5–2 days had either positive or negative effects on the mean particle size. Linear correlation analyses were performed using the data obtained during both transient and steady-state operations of the HL-MBR system. TB-EPS and EPSp showed strong correlations with the biofloccultaion efficiency, whereas loosely bound (LB) EPS correlated with soluble COD removal. TB-EPS and EPSc had negative correlations with the energy recovery potential of the system. The trend of change of parameters affecting membrane fouling with SRT suggested that, in the range studied, the lowest rate of membrane fouling would be expected at SRT of 0.5 days.
23369. 题目: Evaluation of connected clonal growth of Solidago chilensis as an avoidance mechanism in copper-polluted soils
文章编号: N19050206
期刊: Chemosphere
作者: Felipe Lillo, Rosanna Ginocchio, Christopher Ulriksen, Elvira A. Dovletyarova, Alexander Neaman
更新时间: 2019-05-02
摘要: Plant resistance to metals can be achieved by two strategies, tolerance and avoidance. Although metal tolerance has been broadly studied in terrestrial plants, avoidance has been less considered as a strategy to cope with soil metal pollution. Avoidance may be an effective alternative in herbaceous plants with connected clonal growth in environments having high heterogeneity in soil micro-spatial distribution of available metals and other soil conditions (i.e. organic matter). In this study, we performed a laboratory experiment on clonal growth of Solidago chilensis when exposed to copper-spiked soils (800 mg kg−1) at different depths (0, 2, 5 and 8 cm depth), with (20%) and without addition of organic matter to mimic contrasting microhabitats found at smelter hinterlands (i.e. open bare ground and microhabitats below shrubs). Results showed that plants grown in the 2 cm-depth Cu-spiked soils were able to growth and produce ramets and rhizomes. However, increased Cu uptake of plants determined phytotoxic effects and a reduction in clonal spread in the 5 cm- and 8 cm-depth Cu-spiked soils. Addition of organic matter to the Cu-spiked soil layers allowed clonal spread. Considering that ramet and rhizome production is decreased but not inhibited when copper pollution is restricted to the uppermost soil layer (2 cm depth) and that organic matter eliminated soil copper toxicity allowing normal clonal spread, connected clonal growth may be an effective avoidance mechanism of Solidago chilensis, particularly in environments with high heterogeneity in micro-spatial distribution of metals and organic matter in the soil profile and between microhabitats.
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23370. 题目: Effect of environmental factors on the oxidative transformation of cephalosporin antibiotics by manganese dioxides
文章编号: N19050205
期刊: Environmental Science: Processes Impacts
作者: Ming-Hao Hsu, Ting-Hao Kuo, Webber Wei-Po Lai, Ching-Hua Huang, Cheng-Chih Hsu, Yung-En Chen, Angela Yu-Chen Lin
更新时间: 2019-05-02
摘要: This study aimed to explore the oxidation and transformation of the cephalosporins cefotaxime (CTX), cephalexin (CFX), cephradine (CFD), cephapirin (CFP) and cefazolin (CFZ) by δ-MnO2. The results showed that the MnO2 oxidation rate was promoted by environmental factors such as higher MnO2 loading, lower initial cephalosporin concentration and lower solution pH. The inhibitory effect occurred in the presence of dissolved organic matter and dissolved cations (inhibitory capacity: Mn2+ > Ca2+ > Mg2+ > Fe3+). Total organic carbon analysis indicated that the transformation byproducts of the cephalosporins are less reactive and persistent under MnO2 oxidation. Twelve transformation byproducts (9 CFP byproducts and 3 CTX byproducts) were identified, and two oxidative transformation pathways were proposed: one occurred in the cephem for CFP, and the other occurred at the substituent at the amine position for CTX. The effect of solar light on the oxidation of the five cephalosporin antibiotics by δ-MnO2 was also investigated, and the results indicated that the initial dissolution rate of δ-MnO2 under sunlight was approximately eight times faster than that in the dark in the presence of CFP.
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23371. 题目: Reduction of hydraulic conductivity and loss of organic carbon in non-dispersive soils of different clay mineralogy is related to magnesium induced disaggregation
文章编号: N19050204
期刊: Geoderma
作者: Yingcan Zhu, John McLean Bennett, Alla Marchuk
更新时间: 2019-05-02
摘要: Irrigation water containing appreciable amount of magnesium (Mg) is increasingly used in farming. However, studies on the effect of Mg on soil permeability and structural stability are limited and the results are contradicting. In this study, four soils of different dominant clay mineralogy, specifically kaolinite, illite and montmorillonite, were used to investigate the effect of Mg on saturated hydraulic conductivity (Ksat), interaction with organic carbon and soil clay dispersion and to compare to the effect of Ca. The soils were packed in columns and leached with four groups of either Ca-Ca, Ca-Mg, Mg-Mg or Mg-Ca solutions at the successive concentrations of 0.5, 0.25, 0.1, 0.05, 0.025, 0.01, 0.005, 0.001 and 0.0001 M, and finally with deionised water. Ksat was measured and leachates were assessed for dissolved organic carbon (DOC) and dispersion as turbidity. The leached soils were tested for aggregate stability, mechanical dispersion and zeta potential. This study showed that Mg had a disaggregation effect on soil structural stability. As compared to Ca, Ksat on Mg treated cores were lower over a wide range of concentrations, desorption of DOC and turbidity from Mg clay surface was higher, although the dispersion in leachates was insignificant under both Mg and Ca treatments. The effect of Mg treatment was more pronounced on smectic and illitic soils. The decrease in Ksat was related to Mg induced disaggregation, due to intra-crystalline swelling and/or the inter-crystalline swelling in Mg treated soil clays.
23372. 题目: Temporal trends, lake-to-lake variation, and climate effects on Arctic char (Salvelinus alpinus) mercury concentrations from six High Arctic lakes in Nunavut, Canada
文章编号: N19050203
期刊: Science of The Total Environment
作者: Karista E. Hudelson, Derek C.G. Muir, Paul E. Drevnick, Günter Köck, Deborah Iqaluk, Xiaowa Wang, Jane L. Kirk, Benjamin D. Barst, Alice Grgicak-Mannion, Rebecca Shearon, Aaron T. Fisk
更新时间: 2019-05-02
摘要: Climate warming and mercury (Hg) are concurrently influencing Arctic ecosystems, altering their functioning and threatening food security. Non-anadromous Arctic char (Salvelinus alpinus) in small lakes were used to biomonitor these two anthropogenic stressors, because this iconic Arctic species is a long-lived top predator in relatively simple food webs, and yet population characteristics vary greatly, reflecting differences between lake systems. Mercury concentrations in six landlocked Arctic char populations on Cornwallis Island, Nunavut have been monitored as early as 1989, providing a novel dataset to examine differences in muscle [Hg] among char populations, temporal trends, and the relationship between climate patterns and Arctic char [Hg]. We found significant lake-to-lake differences in length-adjusted Arctic char muscle [Hg], which varied by up to 9-fold. Arctic char muscle [Hg] was significantly correlated to dissolved and particulate organic carbon concentrations in water; neither watershed area or vegetation cover explained differences. Three lakes exhibited significant temporal declines in length-adjusted [Hg] in Arctic char; the other three lakes had no significant trends. Though precipitation, temperature, wind speed, and sea ice duration were tested, no single climate variable was significantly correlated to length-adjusted [Hg] across populations. However, Arctic char Hg in Resolute Lake exhibited a significant correlation with sea ice duration, which is likely closely linked to lake ice duration, and which may impact Hg processing in lakes. Additionally, Arctic char [Hg] in Amituk Lake was significantly correlated to snow fall, which may be linked to Hg deposition. The lack of consistent temporal trends in neighboring char populations indicates that currently, within lake processes are the strongest drivers of [Hg] in char in the study lakes and potentially in other Arctic lakes, and that the influence of climate change will likely vary from lake to lake.
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23373. 题目: Labile carbon matters more than temperature for enzyme activity in paddy soil
文章编号: N19050202
期刊: Soil Biology and Biochemistry
作者: Liang Wei, Bahar S. Razavi, Weiqi Wang, Zhenke Zhu, Shoulong Liu, Jinshui Wu, Yakov Kuzyakov, Tida Ge
更新时间: 2019-05-02
摘要: Global warming increases belowground carbon (C) input as plant litterfall, root biomass and rhizodeposition, which influences the stocks and dynamics of soil organic matter. To clarify the effects of labile C availability (biochemical factor) and temperature (environmental factor) on enzyme activities, we incubated typical paddy soil for 75 d at four temperatures (5, 15, 25, and 35 °C) under anaerobic conditions. Acetate was used as the source of labile C and methane. The potential activities of three hydrolases (β-glucosidase, chitinase, and xylanase) were analysed on days 3, 15, and 75 after acetate addition. Activity of β-glucosidase and chitinase in soil without acetate addition was 2.1–2.7 times higher than that with acetate. Xylanase activity increased with temperature and incubation period. The enzymes involved in the C cycle were sensitive to temperature, whereas chitinase (responsible for N cycle) activity became temperature sensitive only after acetate addition (Q10-Vmax ≥ 1). Organic C mineralisation (CO2 release) was more sensitive at low temperature with Q10 values 1.1–3.4 times higher at 5–15 °C than at 25–35 °C. The Q10 values for methane (CH4) emission were 2.8–13.5 times higher at 5–15 °C than at 25–35 °C. Organic matter decomposition in paddy soil was more sensitive to temperature (Q10 of CO2 and CH4 emission ≥ 1) than enzyme activities. Comparison of abiotic (temperature) and biochemical (C availability) effects indicated that warming has limited effects on hydrolase activities in paddy soil. The increase in labile C remarkably stimulated microbial activity and soil organic matter turnover. We conclude that: i) enzyme activities are more sensitive to C addition than to temperature; ii) and SOM decomposition is accelerated by both C input and warming, especially at low temperatures.
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23374. 题目: Stabilization of exogenous carbon in soil density fractions is affected by its chemical composition and soil management
文章编号: N19050201
期刊: Soil and Tillage Research
作者: Husen Qiu, Jieyun Liu, Yajun Hu, Tida Ge, Xiangbi Chen, Yirong Su, Jinshui Wu
更新时间: 2019-05-02
摘要: Low molecular weight organic carbon (LMWOC) can be physiochemically protected by soil particles via sorption and enfolding. Soil management usually changed the soil particle distribution (e.g. upland vs paddy soil). Higher organic carbon stocks in paddy soil than upland soil could partially be because of the greater immobilization and inaccessibility of LMWOC in paddy soil. To assess the effects of soil management and types of LMWOC on its carbon stabilization in soil density fractions, a simulated study was conducted to investigate the distribution of LMWOC (i.e., glucose, acetic acid, and oxalic acid) in soil density fractions based on 13C-labeling experiments in both soils. The results showed that the total 13C recovery was determined by LMWOC types, following the order of glucose> acetic acid > oxalic acid (p < 0.05). Both soil management and types of LMWOC significantly affect carbon distribution in soil density fractions. The 13C from LMWOC was predominant in the 1.85–2.4 g.cm−3 fraction of upland soil, while the highest concentration of LMWOC 13C was found in mineral grains (2.4–2.65 g.cm−3) in paddy soil, suggesting that more LMWOC was preserved in high density fractions in paddy soil than in upland soil. Our results highlighted that the LMWOC was mainly associated with aggregates in upland soil while subjected to mineral adsorption in paddy soil.
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23375. 题目: Removal of dissolved organic matter fractions from reverse osmosis concentrate: Comparing granular activated carbon and ion exchange resin adsorbents
文章编号: N19050115
期刊: Journal of Environmental Chemical Engineering
作者: Shahzad Jamil, Paripurnanda Loganathan, Jaya Kandasamy, Andrzej Listowski, Chinu Khourshed, Ravi Naidu, Saravanamuthu Vigneswaran
更新时间: 2019-05-01
摘要: Reverse osmosis (RO) generates a concentrate (ROC) containing dangerous levels of pollutants including dissolved organic carbon (DOC). Adsorption experiments were conducted to study the effectiveness of removing DOC and its fractions from ROCs produced in a water reclamation plant using three adsorbents tested individually and in sequential combination. The ROCs had 23-42 mg/L DOC which contained 83-90% hydrophilics. These hydrophilics comprised 72-76% humics, 2-3% biopolymers, 5-7% building blocks, and 16-18% low molecular weight neutrals. Granular activated carbon (GAC) removed a larger amount of DOC than two strong base anion exchange resins (Purolite A502PS, Purolite A860S). In both batch and column experiments, the adsorptive removal of the hydrophobic fraction was greater for GAC than for the Purolites. Humics present in hydrophilic fraction was completely removed by Purolites but only partially by GAC. In the sequential adsorption batch experiment, GAC followed by Purolite treatment removed more hydrophobics, however, Purolite followed by GAC removed more humics. Almost 100% of humics was removed for all doses of adsorbents when Purolite served as the first treatment. It is concluded that the order of adsorbent use for effectively treating ROC depends on the target DOC fraction intended to be removed.
23376. 题目: Investigating interactions between sugarcane straw and organic fertilizers recycled together in a soil using modelling of C and N mineralization
文章编号: N19050114
期刊: European Journal of Soil Science
作者: V. Kyulavski, S. Recous, L. Thuries, J.‐M. Paillat, P. Garnier
更新时间: 2019-05-01
摘要: The input of organic fertilizers to soils is an interesting option in substitution for mineral fertilization, but how their interaction with crop residues affects the fate of added carbon (C) and nitrogen (N) in the soil is still poorly known. Therefore, we analysed the effect of adding together organic fertilizer and straw on subsequent C and N mineralization. We incubated sugarcane straw (S), pig slurry (PS) and solid sewage sludge (DS) separately and in mixtures (PS‐S and DS‐S) at 28°C during 182 days. To discuss interactions, we used a simple additivity model based on measurements and a mechanistic model for C and N transformations in soil (CANTIS). Both models overestimated the C mineralization and did not correctly predict N mineralization of the two mixtures. The differences between observed and expected values calculated with the models were negative for C mineralization, indicating an antagonistic interaction in mixtures. The limitations for C decomposition might be the result of many factors like negative priming effect or limitation in N accessibility, which are not considered by CANTIS. We assumed that the priming effect induced by the mineralization of a mixture was not significantly different from the priming effect induced by the mineralization of the organic matters incubated alone. The use of a contact factor in CANTIS allowed the predicted C and N kinetics for the mixtures to be correctly fitted to measured data. It reflects the effect of fine‐scale C and N distribution heterogeneities on the intensity of microbial decomposition. A better integration of the interactions between different N and C sources should be addressed to develop modelling as an accurate tool for agroecosystem management.
23377. 题目: Biochar-based engineered composites for sorptive decontamination of water: A review
文章编号: N19050113
期刊: Chemical Engineering Journal
作者: K.S.D. Premarathna, Anushka Upamali Rajapaksha, Binoy Sarkar, Eilhann E. Kwon, Amit Bhatnagar, Yong Sik Ok, Meththika Vithanage
更新时间: 2019-05-01
摘要: Biochar (BC) exhibits a great potential as an adsorbent in decontamination of water. To improve the adsorption capabilities and impart the particular functionalities of BC, various methods (chemical modification, physical modification, impregnation with different materials, and magnetic modification) have been developed. As compared to surface modifications, BC-based composites provide various technical and environmental benefits because they require fewer chemicals, lesser energy, and confer enhanced contaminant removal capacity. Therefore, this review focuses on BC composites prepared by the combination of BC with different additives including metals, metal oxides, clay minerals, and carbonaceous materials, which greatly alter the physicochemical properties of BC and broaden its adsorption potential for a wide range of aquatic contaminants. Techniques for the preparation of BC composites, their adsorption potentials for a variety of inorganic and organic environmental contaminants, factors affecting BC properties and the adsorption process, and the mechanisms involved in adsorption are also discussed. Modification typically alters the surface properties and functionalities of BC composites including surface area, pore volume, pore size, surface charge, and surface functional groups. Hence, modification enhances the adsorption capacity of BC for most organic and inorganic compounds and ions. Nevertheless, some modifications negatively affect the adsorption of certain contaminants because of various factors including obstruction of pores due to over coating and development of same charge as contaminant on the surface of BC. However, the use of BC composites in environmental remediation is still in its infancy, and further research and development is needed to reach scalability and commercialization of the new technology.
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23378. 题目: Effects of KMnO4/NaHSO3 pre-oxidation on the formation potential of disinfection by-products during subsequent chlorination
文章编号: N19050112
期刊: Chemical Engineering Journal
作者: Yating Zhu, Xin Yang, Junlian Qiao, Xin Zhang, Xiaohong Guan
更新时间: 2019-05-01
摘要: Bisulfite-activated permanganate oxidation (PM/BS) technology is an emerging oxidation process that can rapidly oxidize organic contaminants and degrade some permanganate-resistant organic contaminants. For the first time, the influences of PM/BS technology as a pre-oxidation process on the formation potentials of disinfection by-products (DBPFPs) during chlorination of humic acid (HA) solution and three natural water samples were investigated. The results revealed that PM/BS pre-oxidation only slightly affected the DBPFPs of HA in the absence of Br- although it changed the structure of HA according to the fluorescence characterization result. With the presence of Br-, PM/BS pre-oxidation enhanced the generation of trihalomethanes but inhibited that of nitrogenous DBPs (N-DBPs) during chlorination of HA. The toxic risk analysis showed that the toxicity of the generated DBPs from chlorinating HA solution without Br- only changed slightly after PM/BS pre-oxidation but it was decreased by 14% in the presence of 150 μg/L Br- due to PM/BS pre-oxidation. This should be associated with the inhibiting effect of PM/BS pre-oxidation on the generation of N-DBPs and several haloacetic acids in the presence of Br-. Because of the complex matrix of natural water samples, PM/BS pre-oxidation had minor influence on the amount and the potential toxicity of DBPs generated during chlorination. The above results suggested that PM/BS technology could be an alternative of the drinking water pretreatment.
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23379. 题目: Investigating the use of microdialysis and SEC-UV-ICP-MS to assess iodine interactions in soil solution
文章编号: N19050111
期刊: Chemosphere
作者: O.S. Humphrey, S.D. Young, E.H. Bailey, N.M.J. Crout, E.L. Ander, E.M. Hamilton, M.J. Watts
更新时间: 2019-05-01
摘要: Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I− and IO3− recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ± 7.1 and 70.5 ± 7.1% for I− and IO3−, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I− > IO3−. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter.
23380. 题目: Effect of sodium concentration on mobilization and fate of trace metals in standard OECD soil
文章编号: N19050110
期刊: Environmental Pollution
作者: Ludovico Pontoni, Marco Race, Eric D. van Hullebusch, Massimiliano Fabbricino, Giovanni Esposito, Francesco Pirozzi
更新时间: 2019-05-01
摘要: The effect of different Na concentrations on the fate of trace metals (Cd, Cu, Ni, Zn) in standard OECD soil was evaluated by performing soil leaching column experiments. Five Na concentrations added in synthetic irrigation water (0, 1, 5, 10, 50 mM) were studied in order to evaluate the fate of the metals contained in both the irrigation water leachate and the soil layer. In all experiments, metals mostly accumulated on the top soil layer (0–0.5 cm), at variable concentrations according to the Na content in the artificial irrigation water. Nevertheless, concentration peaks of metal contamination occurred at different sampling time in the soil leachates depending on the metal and on influent water sodicity. Peaks of metals in the leachate appeared simultaneously with the release of organic matter and/or release of Al, suggesting significant involvement of colloids in metals transport. Sodium concentration (10–50 mM) was demonstrated to highly reduce colloidal mobilization leading to the accumulation of more than 95% of the influent metal in the top soil layer. Conversely, low Na concentrations (1–5 mM) favored colloidal transport leading to the recovery of metals in the soil leachates.
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