论文检索

总访问量：3044008次

总访客量：128098人

所有论文

24661. 题目: Effects of natural dissolved organic matter on the complexation and biodegradation of 17α-ethinylestradiol in freshwater lakes
文章编号: N19010807
期刊: Environmental Pollution
作者: Leilei Bai, Qi Zhang, Changhui Wang, Xiaolong Yao, Hui Zhang, Helong Jiang
更新时间: 2019-01-08
摘要: Natural dissolved organic matter (DOM) produced in algal blooms and overgrowths of macrophyte changes the elimination and ecotoxicity of estrogens in freshwater lakes. The complexation of 17α-ethinylestradiol (EE2) and various DOMs, including the water- and sediment-derived DOMs from the algal-dominant zone in Lake Taihu (TW and TS, respectively) and the macrophyte-dominant zone in Poyang Lake (PW and PS, respectively), and the humic acid (HA), was investigated along with the subsequent effects on EE2 biodegradation. Dialysis equilibrium experiments showed that binding to DOM significantly decreased the freely soluble concentrations of EE2. The binding capacity of the five DOMs followed the order of PW < TW < PS ≈ TS < HA. A negative correlation was found between the organic-carbon-normalized sorption coefficient (logK_DOC) and the absorption ratio (E₂/E₃) of DOM, indicating that the large sized, aromatic molecules were involved in the complexation. The reduced freely soluble concentrations of EE2 did not inhibit its biodegradation by an EE2-degrading strain, Rhodobacter blasticus. Conversely, the autochthonous-dominated water-derived DOMs stimulated a more extensive biodegradation of EE2 than the sediment-derived DOMs, and the existence of HA resulted in the smallest increase in EE2 biodegradation. The promoting effect was associated with the increased concentration, activity, and transforming rate of R. blasticus by the bioavailable components in DOM. The present study suggests that the significant impact of natural DOM should be fully considered when assessing the fate and ecological risks of estrogens in eutrophic waters.
图文摘要:

24662. 题目: Fluorescence spectroscopic characterisation of algal organic matter: towards improved in-situ fluorometer development
文章编号: N19010806
期刊: Environmental Science: Water Research & Technology
作者: Sara Imran Khan, Narasinga Rao Hanumanth Rao, Arash Zamyadi, Xiang Li, Richard Stuetz, Rita Henderson
更新时间: 2019-01-08
摘要: Online fluorescence probes have been applied for the rapid detection of cyanobacterial and algal cells via measurement of fluorescent cell pigmentation with some success; however, this alone is not a sufficiently robust method to identify specific species, stage of the bloom, or measure the released organic matter. This study investigates whether fluorescence can be applied to characterise the AOM released by cyanobacterial and algal species which, when combined with cell pigmentation measurements, may improve the specificity and robustness of these online methods. The AOM released by key cyanobacterial (Dolichospermum circinalis, Cylindrospermopsis raciborskii, four strains of Microcystis aeruginosa) and algal (Chlorella vulgaris) species were studied at lab scale throughout their growth using 3D-fluorescent excitation-emission matrix (F-EEMs) spectroscopy combined with Parallel Factor analysis (PARAFAC). A six-component PARAFAC model was developed for the analysed dataset. Analysis of the PARAFAC data indicated that observations of certain wavelengths could be helpful for AOM monitoring in conjunction with cell pigments, giving information on both, bloom health and AOM character. The relevant wavelengths were shown to vary depending on the species; for example, the fluorescence of amino acid-like material at λex/em =290/345 nm dominated in the AOM originating from C. vulgaris, while that of M. aeruginosa (CS-555) was dominated by fluorescence at λex/em =355/475 nm which has previously been associated only with terrestrially delivered substances. Both these fluorescence signatures had significant correlations with the released AOM, measured as dissolved organic carbon (DOC), and dominated across the exponential and stationary phases relative to other PARAFAC components. With fluorescence probes on the market that measure fluorescence in AOM regions, there is an opportunity to monitor these key peaks simultaneously with pigment fluorescence to give further information on the released organic matter character and its treatability.

24663. 题目: Emerging investigator series: Photocatalysis for MBR Effluent Post-Treatment: Assessing the Effects of Effluent Organic Matter Characteristics
文章编号: N19010805
期刊: Environmental Science: Water Research & Technology
作者: Mostafa Maghsoodi, Céline Jacquin, Benoit Teychené, Marc Heran, Volodymyr Tarabara, Geoffroy Lesage, Samuel Snow
更新时间: 2019-01-08
摘要: Dissolved organic matter (DOM) poses a serious challenge to applied photocatalysis. Membranes may offer a promising synergistic opportunity to enable efficient photocatalysts in the presence of DOM. Membrane bioreactor (MBR) effluent from a municipal treatment plant was studied to elucidate the effects of filtration and organic matter composition on photocatalysis. Effluent samples were collected from MBR units during routine operation and before/after chemical cleaning. Additional DOM samples from the bulk supernatant were separated into colloidal, hydrophobic and transphilic fractions, providing a novel examination of the inhibition potential of DOM. These DOM fractions and the effluent organic matter (EfOM) samples were then characterized utilizing three-dimensional excitation–emission matrix (3DEEM) fluorescence spectroscopy and assayed for their potential to inhibit TiO2-mediated photocatalytic degradation of a probe compound, para-chlorobenzoic acid (pCBA). The colloidal fraction of DOM was found to exert the strongest inhibition, followed by the transphilic, then the hydrophobic fractions; at 5 mgC/L, these fractions reduced the photodegradation rates by approximately 75%, 27%, and 17%, respectively. Of the effluent samples, EfOM from the recently-cleaned membrane caused the greatest inhibition of photocatalysis (~100% reduction at 0.5 to 2.0 mgC/L), whereas the effluent from the fouled membrane provided the least inhibition (~33% reduction at 2.0 mgC/L). The 3DEEM analysis predicted inhibitory action of both DOM and EfOM, based on total fluorescence volumes. Results here demonstrate the prospective utility of combining membrane technologies with photocatalytic processes.

24664. 题目: A holistic analysis of ANAMMOX process in response to salinity: from adaptation to collapse
文章编号: N19010804
期刊: Separation and Purification Technology
作者: Lu Huifeng, Li Yiyu, Shan Xiaoyu, Ghulam Abbas, Zeng Zhuo, Kang Da, Wang Yayi, Zheng Ping, Zhang Meng
更新时间: 2019-01-08
摘要: The application of anaerobic ammonium oxidation (ANAMMOX) process to industrial wastewater treatment usually faces the challenge of high salinity. However, most of the current ANAMMOX sludge was enriched from low-salinity water, resulting in the critical gap between the inoculum and saline wastewater. In this work, an ANAMMOX reactor fed with inoculum enriched from low-salinity water successfully adapted to saline wastewater (500 mmol/L NaCl, 2.92%) after a long-term stepwise acclimatization. The nitrogen removal rate and total nitrogen removal efficiency reached 9.72 kg·m^-3·d^-1 and 80.90%, respectively. However, further salinity increase to 600 mmol/L caused a collapse of reactor performance. The inorganic matters’ proportion improved along with the salinity increase, which might be attributed to the compact particles observed in the microstructure of ANAMMOX sludge. A microbial community succession occurred in response to the salinity increase. When the salinity increased to 160 mmol/L, the dominant functional bacteria shifted from Candidatus Kuenenia to unclassified Brocadiaceae, which was supposed to be salt-tolerant. The up and down regulations of polysaccharides and ζ potential in EPS were positive strategies for salinity adaptation of ANAMMOX bacteria. However, the barrier of seawater salinity (3-5%) could not be overcome. The present work would provide holistic view for the enrichment of salt-tolerant AnAOB and help in the selection of seeding sludge for the treatment of saline wastewater by ANAMMOX process.
图文摘要:

24665. 题目: Synergistic effects of surfactant-assisted biodegradation of wheat straw and production of polysaccharides by Inonotus obliquus under submerged fermentation
文章编号: N19010803
期刊: Bioresource Technology
作者: Xiangqun Xu, Pan Wu, Tianzhen Wang, Lulu Yan, Mengmeng Lin, Cui Chen
更新时间: 2019-01-08
摘要: Current work proposes an innovative wheat straw biomass utilization strategy that connects efficient lignocellulose biodegradation with exo-polysaccharide (EPS) production in I. obliquus under submerged fermentation. The addition of Tween 80 increased the activities of ligninolytic enzymes MnP, LiP and Lac by 1200%, 125% and 39.9%, respectively. When wheat straw lignin recalcitrance was substantially reduced with the aid of Tween 80, I. obliquus was capable of utilizing the substrates and in turn accumulated EPS. The degradation of cellulose, hemicellulose and lignin reached 46.1%, 46.4% and 44.1% on Day 9 of growth, respectively. Meanwhile, the maximum mycelial biomass and EPS production increased by 23.3% and 142.9%, respectively. The EPS had higher contents of sugar, protein, uronic acid, and mannose ratio, and higher antioxidant activity against 2, 2 - diphenyl - 1 - picrylhydrazyl (DPPH), 2, 2 - azinobis - (3 - ethylbenzothiazoline - 6 - sulfonic acid) (ABTS^•+) and hydroxyl radicals.
图文摘要:

24666. 题目: Investigating the impact of anthropogenic land use on a hemiboreal lake ecosystem using carbon/nitrogen ratios and coupled-optical emission spectroscopy
文章编号: N19010802
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: N. Stivrins, M. Liiv, A. Brown, R.Y. Banerjea, A. Heinsalu, S. Veski
更新时间: 2019-01-08
摘要: Anthropogenic impacts on lake ecosystems have increased substantially towards the present. However, the strength and timing in most cases are not evaluated in detail, missing valuable information on the response and recovery of an aquatic system. In this study, we use the sediment total organic carbon/total nitrogen ratio (C/N) and inductively coupled-optical emission spectroscopy (ICP-OES) elements and the available information about the biological processes to explore anthropogenic land use impact on the lake ecosystem. As a case study we selected a hemiboreal lake Trikātas (Latvia, NE Europe). The Pearson correlation was used to statistically test the correlations of all variables. Our results show that the C/N ratio lowered immediately with the onset of crop cultivation at 500 BCE. Extensive forest clearance and an abrupt increase in land use are reflected through the associated chemical elements from ICP-OES and the increasing presence of herbivore dung spores since 1200 CE. These changes concur with the excess of fish remains suggesting a decrease in fish populations. Interestingly, anthropogenic land use driven erosion and accompanied calcium carbonate (CaCO₃) matter influx favoured the abundance of Chara spp. in Lake Trikātas since 500 CE, which currently forms the protected specific habitat-type (H3140) of the European Union. At present, specific submerged macrophyte Chara habitat-type diminished almost entirely due to increased nutrient input, phytoplankton blooming, hypertrophic conditions and reduced light availability. The continued land use practices led to a switch in organic matter source in the lake from macrophytes to solely algal origin. The current study underlines the need of additional methods used to detect the sensitivity of lake ecosystem to external disturbances such as minor anthropogenic land use that might not necessarily be apparent in more traditional analyses such as palynology.

24667. 题目: Carbon outwelling and emissions from two contrasting mangrove creeks during the monsoon storm season in Palau, Micronesia
文章编号: N19010801
期刊: Estuarine, Coastal and Shelf Science
作者: Mitchell Call, Christian J. Sanders, Paul A. Macklin, Isaac R. Santos, Damien T. Maher
更新时间: 2019-01-08
摘要: Mangroves sequester large amounts of carbon in soils but limited information is available on carbon losses from tropical mangrove systems. Here we quantify carbon outwelling, CO₂ emissions and pore-water exchange rates from two nearby (∼2 km apart) tropical mangrove creeks located in different geomorphic settings on the island of Palau, Micronesia during the monsoonal storm season. On average, POC and pCO₂ were >100% higher and DOC, DIC and TA were 62%, 25%, 16% higher, respectively, from Creek 1 (located within a semi-enclosed bay) than from Creek 2 (located along the coast adjacent to fringing reefs). Both creeks were net exporters of DIC, DOC, POC and emitters of CO₂. However, outwelling rates of POC, DIC and DOC and CO₂ emissions were 27-fold, 8-fold, 4-fold and 3-fold higher at Creek 1. DIC outwelling (37%) and CO₂ emissions (39%) were the major terms contributing to total carbon losses at Creek 1, whilst CO₂ emission (61%) was the major contributor at Creek 2. Monsoon storms appeared to explain the organic carbon dynamics whilst tidal pumping appears to drive the inorganic carbon dynamics at both creeks. Our data demonstrates the considerable heterogeneity of mangroves creeks that are in close proximity and subject to similar weather conditions but in differing geomorphological settings.

24668. 题目: The effects of humic water on endothelial cells under hyperglycemic conditions: inflammation-associated parameters
文章编号: N19010709
期刊: Environmental Geochemistry and Health
作者: Katarzyna Szot, Krzysztof Góralczyk, Małgorzata Michalska, Natallia Veryho, Jacek Chojnowski, Irena Ponikowska, Danuta Rość
更新时间: 2019-01-07
摘要: Humic waters (HW) are globally unique, deep underground, dark-brown waters containing humic acids, and they present numerous therapeutic activities including anti-inflammatory. In the present study, we use HW from source in Poland. Diabetes has become an epidemic and is a risk factor of cardiovascular diseases. Hyperglycemia in diabetes is responsible for damaging of the endothelium and increases inflammation on the surface of the vascular lining. The inflammatory process in diabetes is associated with the secretion of inflammatory cytokines by endothelial cells, e.g., tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), and with the reduction of cell proliferation. In the study, we used cultures of endothelial cells (HUVEC line—human umbilical vein endothelial cells) with the addition 30 mM/L of glucose in the culture medium which imitated the conditions of uncontrolled diabetes. The addition of HW in the proper volume to the culture medium causes reduction of inflammation by significant decrease in inflammatory cytokines such as TNFα and IL-6 and also leads to enhancement of the cell proliferation. It appears that the adverse effects of hyperglycemia on vascular endothelial cells may be corrected by addition of humic water. The above promising results of in vitro tests provide an opportunity to the possible use of humic water in the supportive treatment of endothelial dysfunction disorders in diabetes. However, this issue requires further clinical research.

24669. 题目: Quantifying degradative loss of terrigenous organic carbon in surface sediments across the Laptev and East Siberian Sea
文章编号: N19010708
期刊: Global Biogeochemical Cycles
作者: Lisa Bröder, August Andersson, Tommaso Tesi, Igor Semiletov, Örjan Gustafsson
更新时间: 2019-01-07
摘要: Ongoing permafrost thaw in the Arctic may remobilize large amounts of old organic matter. Upon transport to the Siberian shelf seas, this material may be degraded and released to the atmosphere, exported off‐shelf or buried in the sediments. While our understanding of the fate of permafrost‐derived organic matter in shelf waters is improving, poor constraints remain regarding degradation in sediments. Here, we use an extensive dataset of organic carbon concentrations and isotopes (n=109) to inventory terrigenous organic carbon (terrOC) in surficial sediments of the Laptev and East Siberian Seas (LS+ESS). About 55 % of these ~2.7 Tg terrOC appear resistant to degradation on a millennial timescale. A first‐order degradation rate constant of 1.5 kyr‐1 is derived by combining a previously established relationship between water depth and cross‐shelf sediment‐terrOC transport time with mineral‐associated terrOC loadings. This yields a terrOC degradation flux of ~1.7 Gg yr‐1 from surficial sediments during cross‐shelf transport, which is orders of magnitude lower than earlier estimates for degradation fluxes of dissolved and particulate terrOC in the water column of the LS+ESS. The difference is mainly due to the low degradation rate constant of sedimentary terrOC, likely caused by a combination of factors: (i) the lower availability of oxygen in the sediments compared to fully oxygenated waters, (ii) the stabilizing role of terrOC‐mineral associations and (iii) the higher proportion of material that is intrinsically recalcitrant due to its chemical/molecular structure in sediments. Sequestration of permafrost‐released terrOC in shelf sediments may thereby attenuate the otherwise expected permafrost carbon‐climate feedback.

24670. 题目: Dissolved organic matter chemistry and transport along an Arctic tundra hillslope
文章编号: N19010707
期刊: Global Biogeochemical Cycles
作者: Laurel M. Lynch, Megan B. Machmuller, Claudia M. Boot, Timothy P. Covino, Christopher D. Rithner, M. Francesca Cotrufo, David W. Hoyt, Matthew D. Wallenstein
更新时间: 2019-01-07
摘要: Permafrost thaw is projected to restructure the connectivity of surface and subsurface flowpaths, influencing export dynamics of dissolved organic matter (DOM) through Arctic watersheds. Resulting shifts in flowpath exchange between both soil horizons (organic‐mineral) and landscape positions (hillslope‐riparian) could alter DOM mobility and molecular‐level patterns in chemical composition. Using conservative tracers, we found relatively rapid lateral flows occurred across a headwater Arctic tundra hillslope, as well as along the mineral‐permafrost interface. While pore waters collected from the organic horizon were associated with plant‐derived molecules, those collected from permafrost‐influenced mineral horizons had a microbial origin, as determined by fluorescence spectroscopy. Using high‐resolution NMR spectroscopy, we found that riparian DOM had greater structural diversity than hillslope DOM, suggesting riparian soils could supply a diverse array of compounds to surface waters if terrestrial‐aquatic connectivity increases with warming. In combination, these results suggest integrating DOM mobilization with its chemical and spatial heterogeneity can help predict how permafrost loss will structure ecosystem metabolism and carbon‐climate feedbacks in Arctic catchments with similar topographic features.

24671. 题目: Detection of transient denitrification during a high organic matter event in the Black Sea
文章编号: N19010706
期刊: Global Biogeochemical Cycles
作者: Clara A. Fuchsman, Barbara Paul, James T. Staley, Evgeniy V. Yakushev, James W. Murray
更新时间: 2019-01-07
摘要: N₂ production by denitrification can occur in anoxic water or potentially inside organic particles. Here we compare data from the Black Sea, a permanently anoxic basin, during two organic matter regimes: suspended particulate organic matter concentrations were high in the oxycline after the spring bloom in March 2005 compared to lower organic matter concentrations in June 2005, May and October 2007, July 2008 and May 2001. For all cruises, N₂ gas had a maximum in the suboxic zone [O₂ <10 μmol L^‐1]. During the high organic matter event [March 2005], an additional shallower N₂ gas and δ¹⁵N‐N₂ maxima occurred above the suboxic zone in the oxycline where oxygen concentrations were 30‐50 μmol L^‐1. Examination of 16S rRNA indicated that anammox bacteria were not present in the oxycline. The δ¹⁵N of biologically produced N₂ in the oxycline in March 2005 was significantly enriched (+7 to +38‰), not depleted, as would be expected from water column fractionation. A simple diffusion calculation indicated that ammonium produced from remineralization inside particles could be oxidized to nitrate and then completely consumed by denitrification inside the particle. In this calculation, half of denitrified N atoms originated from organic N [δ¹⁵N = 11‰] and half of N atoms originated from ambient nitrate [δ¹⁵N = 5‐7‰], producing enriched δ¹⁵N‐N₂ values. We suggest that denitrifiers were active in microzones inside particulates in hypoxic waters above the suboxic zone of the Black Sea. Denitrification in particles may also explain previous data from the oxycline above ocean oxygen deficient zones.

24672. 题目: Impacts of wise grazing on physicochemical and biological features of soil in a sandy grassland on the Tibetan Plateau
文章编号: N19010705
期刊: Land Degradation & Development
作者: Nan Nan Zhang, Geng Sun, Bo Zhong, En Tao Wang, Chun Zhang Zhao, Yan Jie Wang, Wei Cheng, Ning Wu
更新时间: 2019-01-07
摘要: Desertification is a serious environmental problem on the Tibetan Plateau and various strategies, such as long‐term fencing and grazing management, have been implemented in that region to control the soil degradation. However, little is known about the role of interactions among the soil aggregate, microbial communities, and nutrient traits in the soil restoration. In this study, we compared the effects of different restoration strategies on the formation of aggregates, the amount and distribution of soil nutrients, as well as the abundance and diversity of bacteria in a sandy soil of grassland at the Tibetan Plateau. The results demonstrated that both the grazing exclusion (GE: artificial planting and nutrient addition) and wise grazing (WG: artificial planting and nutrient addition with controlled grazing) treatments significantly increased the proportion of macroaggregates (4.0 and 5.2 times, P < 0.05) compared with the control. Increased soil organic carbon (SOC), total carbon (TC), total nitrogen (TN), and total phosphorus (TP) were found in the aggregates of WG treatment, but not in the GE samples. In addition, WG significantly changed the bacterial composition and increased bacterial abundance in soil. This study evaluated WG as an efficient management for restoration of degraded sandy grassland in the Tibetan Plateau since it significantly enriched the soil nutrients, improved the soil structure and increased bacterial abundance. This is the first study to relate the aggregates with nutrient accumulation and bacterial community during the soil restoration in the Tibetan Plateau.

24673. 题目: The effect of redox capacity of humic acids on hexachlorobenzene dechlorination during the anaerobic digestion process
文章编号: N19010704
期刊: Environmental Science and Pollution Research
作者: Dongyang Li, Beidou Xi, Yingjun Li, Xiaowei Wang, Tianxue Yang, Hong Yu, Caihong Huang, Jianchao Zhu, Qi Li, Xing Peng, Zhifei Ma
更新时间: 2019-01-07
摘要: Hexachlorobenzene (HCB) dechlorination affected by humic acids (HA) was evaluated in terms of HA redox capacity, HA concentrations, and microbial community, as well as the correlation between HA redox capacity values and HCB concentrations. With addition of HA in the initial stage, redox capacity values increased by 2.19 meq/L (80 mg/L of HA addition, HA₈₀), 2.51 meq/L (120 mg/L of HA addition, HA₁₂₀), and 3.64 meq/L (200 mg/L of HA addition, HA₂₀₀), respectively. The addition of HA could prominently enhance the HCB degradation rate. However, the concentration and the redox capacity of HA decreased during the anaerobic digestion process. Illumina MiSeq sequencing showed that microbial community affected by HA. Bacillus, Comamonas, and Pseudomonas were the predominant genera during the HCB dechlorination treatment. Moreover, Bacillus and Pseudomonas can improve HA electron transfer capability and promote the dechlorination of HCB.

24674. 题目: Non-additive responses of soil C and N to rice straw and hairy vetch ( Vicia villosa Roth L. ) mixtures in a paddy soil
文章编号: N19010703
期刊: Plant and Soil
作者: Guopeng Zhou, Weidong Cao, Jinshun Bai, Changxu Xu, Naohua Zeng, Songjuan Gao, Robert M. Rees
更新时间: 2019-01-07
摘要: Aims: We studied the effects of mixing rice straw and hairy vetch plant residues in a subtropical paddy soil, on subsequent carbon (C) and nitrogen (N) dynamics. Methods: Using a theoretical framework, we designed two groups of experiments (involving equal amounts of residual C or N addition, referred to as either C or N treatments). Each experiment included mixed residues of rice straw and hairy vetch at different mixing ratios. Soils together with residues were incubated at 25 °C under waterlogged conditions for 100 days. Greenhouse gas (GHG) emissions and soil C and N fractions were measured continuously. Results: Both C and N treatments affected soil C and N dynamics, and these dynamics were quantitatively dependent on residue C/N ratios. The effect of residue mixtures on C and N dynamics could not be predicted from single residues, since there were non-additive effects of residue mixtures. Synergistic effects were generally more frequent than antagonistic effects. Residue mixtures tended to enhance CO₂ and CH₄ emissions in both C and N treatments but decreased N₂O emissions in the N treatment. In the N treatment, dissolved organic C (DOC), dissolved organic N (DON), and microbial biomass C (MBC) concentrations increased. DOC and DON concentrations decreased in the C treatment. Residue mixtures enhanced the global warming potentials (GWP) of greenhouse gases (GHG) emitted from soil by non-additive synergistic effects. The C/N ratio of residue mixtures affected the non-additive responses of soil C and N dynamics, for example mixtures with a C/N ratio of 25 had higher CO₂ emissions and DOC concentrations than those with a C/N ratio of 35 as a consequence of non-additive effects, however, CH₄ emissions and MBC concentrations were higher in mixtures with a C/N ratio of 35 than in mixtures with a C/N ration of 25. Conclusions: These results indicated that non-additive effects can impact soil C and N dynamics and that residue C/N ratios play an important role in influencing non-additive effects. Applying a single residue to paddy soils may be better than residue mixtures from a GWP mitigation perspective.

24675. 题目: Efficient removal of Cd(II), Cu(II), Pb(II), and Zn(II) from wastewater and natural water using submersible device
文章编号: N19010702
期刊: Environmental Science and Pollution Research
作者: Boris S. Smolyakov, Alexei K. Sagidullin, Roman E. Romanov, Nadezhda I. Yermolaeva
更新时间: 2019-01-07
摘要: In this study, a simple submersible device was tested to remove and recover Cd(II), Cu(II), Pb(II), and Zn(II) from model wastewater and real natural water. To obtain this device, fine particles (< 0.1 mm) of a new hybrid adsorbent based on the mesoporous carbon and Fenton-modified humic acids were fixed onto a highly porous polymeric matrix. The hybrid adsorbent was characterized by various methods. The main mechanism for Cd(II), Cu(II), Pb(II), and Zn(II) adsorption by the hybrid adsorbent is chemosorption by surface functional groups, the total concentration of which was found to be 1.56 mmol g⁻¹. The adsorption capacity depends on pH, and at pH 6.0, it has the following order (mmol g⁻¹): Cu(II) (1.14) > Pb(II) (0.86) > Zn(II) (0.59) > Cd(II) (0.50). The possibility of applying a submersible device for the removal and recovery of these metals from multi-metal wastewaters and reservoirs was studied. A high efficiency of metal removal (95–99.9%) and recovery (85–99%) from wastewater remained in at least six consecutive adsorption–desorption cycles. Effective removal of metals from the water of a contaminated reservoir contributed to the rapid restoration of the phytoplankton organisms after their oppression by metals. Thus, the use of a submerged device with the new hybrid adsorbent can be an effective way of remediating wastewaters and natural waters contaminated with metals.

24676. 题目: Adsorption and regeneration characteristics of phosphorus from sludge dewatering filtrate by magnetic anion exchange resin
文章编号: N19010701
期刊: Environmental Science and Pollution Research
作者: Mingyang Song, Min Li
更新时间: 2019-01-07
摘要: Removal and recovery of phosphorus (P) from sewage are essential for sustainable development of P resource. Based on the water quality determination of sludge dewatering filtrate from a wastewater treatment plant in Beijing, this study investigated the adsorption and regeneration characteristics of P by magnetic anion exchange resin (MAEX). The experiments showed that the P adsorption capacity of MAEX could reach a maximum of 2.74 mg/mL when initial P concentration was 25 mg/L and dosage of MAEX was 8 mL/L. The P adsorption on MAEX resin was suitable for large temperature range (283–323 K). However, the adsorption capacity was reduced in various degrees due to the interference of different anions (Br⁻, SO₄²⁻, Cl⁻, NO₃⁻, HCO₃⁻, CO₃²⁻) and organic compounds (bovine serum albumin, humic acid). Kinetics studies indicated that the P adsorption process followed the pseudo-second-order model. The MAEX resin had a rapid P adsorption rate and the P adsorption capacity at 30 min could reach 97.7–99.3% of q_e. Increase of temperature was favorable to P adsorption on MAEX, and the adsorption isotherm data fitted to Langmuir model more than Freundlich model. Meanwhile, the thermodynamics parameters were calculated; it was shown that the adsorption process was an endothermic reaction. Desorption and regeneration experiments showed that NaHCO₃ was a suitable regenerant, and the P adsorption capacity could reach 90.51% of the original capacity after 10 times of adsorption-desorption cycles; this indicated that MAEX resin has an excellent regeneration performance and thus has a very good application prospect of P removal and recovery. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that ion exchange, charge attraction, and hydrogen bonding affected the removal of P by the MAEX resin. The vibrating sample magnetometer (VSM) analysis revealed that MAEX resin was a kind of soft magnetic materials with good magnetism.

24677. 题目: Effect of tobacco stem-derived biochar on soil metal immobilization and the cultivation of tobacco plant
文章编号: N19010614
期刊: Journal of Soils and Sediments
作者: Jin Zhang, Jianyun Zhang, Minyan Wang, Shengchun Wu, Hailong Wang, Nabeel Khan Niazi, Yu Bon Man, Peter Christie, Shengdao Shan, Ming Hung Wong
更新时间: 2019-01-06
摘要: Purpose: Tobacco stems collected from tobacco cultivation fields were pyrolyzed to produce value-added biochar that was used to remediate metal-contaminated soil which was then used for tobacco cultivation. The feasibility of the scheme was evaluated. Materials and methods: A pot experiment was carried out to assess the impacts of tobacco stem-derived biochar (TSB 0, 2, 4, and 8%) on tobacco growth and leaf yields, soil properties, the availability of soil Cr, Cu, and Pb, and the accumulation of the three metals in tobacco plants. Results and discussion: Soil pH, organic matter content, and available phosphorus content increased with increasing application of TSB from 2 to 8% compared to the control (no biochar addition). In contrast, the acid-soluble and the reducible fractions of soil Cu and the reducible fraction of soil Pb and Cr decreased markedly, and the oxidizable fraction of the metals increased significantly with increasing application of TSB. This indicates that adding more TSB led to increasing immobilization of all three metals in the soil. Furthermore, both the number of tobacco leaves and the foliar biomass increased significantly with the addition of TSB to the soil. Based on our data, 4% is an economically suitable application rate of TSB for decreasing metal accumulation in plants and increasing tobacco leaf yields. Conclusions: The results indicate that it is feasible to use biochar derived from tobacco stem waste to remediate metal-contaminated soils which can then be used for tobacco cultivation. This is very useful in the recycling of the waste biomass and for remediation of soil metal pollution.

24678. 题目: Redox characterization of humins in sediments from the Yangtze Estuary to the East China Sea and their effects on microbial redox reactions
文章编号: N19010613
期刊: Journal of Soils and Sediments
作者: Chunfang Zhang, Shaohong You, Hongyue Dang, Zhiling Li, Qinglin Xie, Dongdong Zhang
更新时间: 2019-01-06
摘要: Purpose: Humins, as solid-phase redox mediators, are important for enhancing anaerobic biotransformation processes. Although humins are broadly distributed in estuarine and marine sediments, to date, their electron transfer capacity (ETC) from marine sediments has been poorly characterized. This study determined the potential of humins as redox mediators for microbial redox metabolic reactions in sediments along a transect from the Yangtze Estuary to the adjacent East China Sea and analyzed their electron-mediating characteristics. Materials and methods: Comparative analyses of humins in sediments along this transect were conducted to investigate their ETC as redox mediators for microbial redox metabolic reactions, namely dissimilatory iron reduction (DIR) and dissimilatory nitrate reduction to ammonium (DNRA), using Shewanella oneidensis MR-1. Elemental composition, electrochemical, and Fourier transform infrared analyses were performed to better understand the functional redox groups in humins. Results and discussion: All the humins functioned as solid-phase redox mediators and enhanced DIR and DNRA by Shewanella oneidensis, although with varying efficacy. The humins extracted from sampling site P1 (P1-HM), located close to the Yangtze Estuary, most effectively enhanced iron and nitrate reduction without nitrite accumulation. Electrochemical analysis confirmed the highest redox activity and ETC in P1-HM and a weakening trend of ETC with increasing distance from the estuary. Fourier transform infrared analysis suggested that quinone moieties might serve as key redox functional groups in humins. Conclusions: Considering their high yield and ETC, P1-HM could be important redox mediators that influence microbial redox metabolic reactions in sedimentary ecosystems of the Yangtze Estuary. Thus, this study provides insights into the distribution of humins, their ECT, and their potential role as redox mediators for microbial redox reactions, which could improve understanding of elemental biogeochemical cycling processes involving microorganisms in the Yangtze Estuary and East China Sea sedimentary ecosystems and provide important reference information for researches on other estuary areas.

24679. 题目: Organic micropollutants’ distribution within sludge organic matter fractions explains their dynamic during sewage sludge anaerobic digestion followed by composting
文章编号: N19010612
期刊: Environmental Science and Pollution Research
作者: Quentin Aemig, Nicolas Doussiet, Alice Danel, Nadine Delgenès, Julie Jimenez, Sabine Houot, Dominique Patureau
更新时间: 2019-01-06
摘要: The simultaneous fate of organic matter and 4 endocrine disruptors (3 polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, benzo(b)fluoranthene, and benzo(a)pyrene) and nonylphenols (NP)) was studied during the anaerobic digestion followed by composting of sludge at lab-scale. Sludge organic matter was characterized, thanks to chemical fractionation and 3D fluorescence deciphering its accessibility and biodegradability. Total chemical oxygen demand (COD) removal was 41% and 56% during anaerobic digestion and composting, respectively. 3D fluorescence highlighted the quality changes of organic matter. During continuous anaerobic digestion, organic micropollutants’ removal was 22 ± 14%, 6 ± 5%, 18 ± 9%, and 0% for fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols, respectively. Discontinuous composting allowed to go further on the organic micropollutants’ removal as 34 ± 8%, 31 ± 20%, 38 ± 10%, and 52 ± 6% of fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols were dissipated, respectively. Moreover, the accessibility of PAH and NP expressed by their presence in the various sludge organic matter fractions and its evolution during both treatments was linked to both the quality evolution of the organic matter and the physicochemical properties of the PAH and NP; the presence in most accessible fractions explained the amount of PAH and NP dissipated.

24680. 题目: Magnetic nanoferromanganese oxides modified biochar derived from pine sawdust for adsorption of tetracycline hydrochloride
文章编号: N19010611
期刊: Environmental Science and Pollution Research
作者: Jie Liang, Yilong Fang, Yuan Luo, Guangming Zeng, Jiaqin Deng, Xiaofei Tan, Ning Tang, Xuemei Li, Xinyue He, Chunting Feng, Shujing Ye
更新时间: 2019-01-06
摘要: In this study, a new type of composite material, namely modified biochar (MBC), was synthesized by loading the magnetic ferromanganese oxide nanoparticles on pine biochar. BET, SEM, and FTIR were employed to analyze the surface properties and pore structures of MBC. In addition, XRD was adopted to examine the crystal structure of MBC. Characterization results showed that the surface area and porosity of MBC have been greatly improved, and the functional groups have been introduced by ferromanganese oxides. Adsorption experiments of tetracycline hydrochloride (TC) including kinetics, isotherms, thermodynamics as well as the influence of pH, salt ion strength, and the environmental risk of MBC, were evaluated. The results revealed that the experimental data conformed to the pseudo-second-order kinetic model and the Freundlich isotherm model. In the adsorption process, MBC showed excellent adsorption ability (maximum capacity for TC 100.74 mg g⁻¹) to BC (33.76 mg g⁻¹). In isotherm experiments, the maximum adsorption capacity of TC by MBC reached 177.71 mg g⁻¹. Toxicity studies showed that the MBC had no harm to the environment. To conclude, MBC has great potential for applications in removing TC from water.