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1.
Xue P Yan C Sun G Luo Z 《Environmental science and pollution research international》2012,19(9):3969-3976
Introduction
Ceratophyllum demersum L. is a widespread submerged macrophyte in aquatic environments.Methods
Simulation experiments were conducted in the laboratory to investigate arsenic (As) accumulation, speciation, and efflux of C. demersum exposed to arsenate and arsenite solutions.Results
Plant shoots showed a significant accumulation of As with a maximum of 862 and 963???g?As?g?1 dry weight after 4?days of exposure to 10???M arsenate and arsenite, respectively. Regardless of whether arsenate or arsenite was supplied to the plants, arsenite was the predominant species in plant shoots. Furthermore, a dramatically higher influx rate of arsenate compared with arsenite was observed in C. demersum exposed to As solutions without the addition of phosphate (P). Arsenate uptake was considerably inhibited by P in this study, suggesting that arsenate is taken up by C. demersum via the phosphate transporters. However, arsenite uptake was unaffected by P and markedly reduced in the presence of glycerol and antimonite (Sb), indicating arsenite shares the aquaporin transport pathway. In addition, C. demersum rapidly reduces arsenate to arsenite in the shoot of the plant and extrudes most of them (>60?%) to the external solutions. The efflux of arsenite was much higher than that of arsenate; the former is supposed to be both active and passive processes, and the latter through passive leakage.Conclusion
C. demersum is a strong As accumulator and an interesting model plant to study As uptake and metabolism due to the lack of a root-to-shoot translocation barrier. 相似文献2.
Bakircioglu D 《Environmental science and pollution research international》2012,19(6):2428-2437
Purpose
An online cloud-point extraction (CPE) coupled with flow injection method is developed for the separation and preconcentration of palladium and lead from various matrices using flame atomic absorption spectrometry (FAAS).Method
The method employs the formation of complexes of the metallic species with dimethylglyoxime, which are subsequently entrapped in the micelles of the surfactant Triton X-114, upon increase of the solution temperature to 60°C and loaded into the flow injection system at a flow rate of 4.6?mL?min?1. The surfactant rich-phase was retained in a minicolumn packed with animal wool at pH?6 and eluted with 1.0?mol?L?1 nitric acid in methanol at a flow rate of 1.1?mL?min?1 directly into the nebulizer of the FAAS. The CPE variables and flow injection conditions affecting the analytical performance of the combined methodology was studied and optimized.Results
Under the optimized conditions for 25?mL of preconcentrated solution, the enrichment factors were 51 and 44, and the limit of detections were 1.0 and 1.4?ng?mL?1 for palladium and lead, respectively. Finally, the developed method was applied for the determination of palladium and lead in street dust, soil, radiology waste, catalytic converter, and urban aerosol samples.Conclusions
Cloud-point extraction coupled with flow injection-FAAS was proposed as an effective preconcentration and separation method for Pd and Pb determination in radiology waste, road dust, soil, and urban aerosol samples. The most favorable feature of this method is its much higher selectivity, sensitivity, rapidity, good extraction efficiency, and employs the green chemistry concept, as it does not require the addition of toxic chemicals. In addition, this proposed method gives very low detection limits and good relative standard. 相似文献3.
Introduction
This study collected long-term airborne lead concentrations in the Korean peninsula and analyzed their temporal, spatial, and cancer risk characterization.Methods
Approximately, 12,000 airborne samples of total suspended particulate (TSP) were collected from 30 ambient air monitoring stations in inland (Daegu, Daejeon, Gwangju, and Seoul) cities and portal cities (Incheon, Busan, and Ulsan) over a period of 7?years (2004?C2010). High volume air samplers were employed to collect daily TSP samples during the second week of the consecutive months throughout the entire study period. The concentrations of Pb extracted from the TSP samples were analyzed using either inductively coupled plasma-atomic emission or flame atomic absorption spectrometry.Results
The long-term high mean Pb concentrations were observed in the port cities including Incheon (88?±?18?ng/m3), Ulsan (61?±?7?ng/m3), and Busan (58?±?6?ng/m3). In the temporal analysis, seasonal mean Pb levels were relatively higher in winter and spring than those in summer and fall. In the spatial analysis, the mean Pb levels in spring, winter, and fall from Incheon, which showed the highest seasonal concentrations except summer, were 110?±?19, 101?±?18, and 76?±?23?ng/m3, respectively. In summer, the highest seasonal mean Pb level was observed in the largest industrial city and the second port city, Ulsan (78?±?15?ng/m3), followed by Incheon (65?±?13?ng/m3).Conclusion
The estimated excess cancer risk analysis showed that inhalation of Pb could result in cancer for one or two persons per million of population in the Korean peninsula. 相似文献4.
Başak S Cokgör EU Insel G Orhon D 《Environmental science and pollution research international》2012,19(8):3412-3420
Background
This study investigated the acute effect of benzo[a]anthracene, a significant compound among polycyclic aromatic hydrocarbons, on the biodegradation of a synthetic organic substrate??a peptone/meat extract mixture??under aerobic conditions.Methods
A laboratory-scale sequencing batch reactor was sustained at steady state at a sludge age of 10?days with substrate feeding. Inhibition tests involved running a series of batch reactors initially seeded with the biomass obtained from the parent reactor. After the biomass seeding, the reactors were started with the peptone mixture and a range of initial benzo[a]anthracene concentrations between 0.5 and 88?mg/L. Experimental profiles of oxygen uptake rates and polyhydroxyalkanoates were evaluated by calibration of a selected model.Results
Lower doses of benzo[a]anthracene had no effect on process kinetics. The noticeable acute impact was only observed with the addition of 88?mg/L of benzo[a]anthracene, but it was limited with the storage mechanism: the amount of organic substrate diverted to polyhydroxyalkanoates was significantly reduced with a corresponding decrease in the maximum storage rate, k STO, from 2.7 down to 0.6?day?1. Similarly, the maximum growth rate from internally stored polyhydroxyalkanoates was lowered from 2.3 to 1.0?day?1.Conclusion
Among the mechanisms for direct substrate utilization, only the hydrolysis rate was slightly reduced, but otherwise, the overall COD removal efficiency was not affected. 相似文献5.
Testolin RC Tischer V Lima AO Cotelle S Férard JF Radetski CM 《Environmental science and pollution research international》2012,19(6):2186-2194
Background, aim and scope
Agrochemicals could reach aquatic ecosystems and damage ecosystem functionality. Natural formicide could be an alternative to use in comparison with the more toxic formicides available on the market. Thus, the objective of this study was to assess the ecotoxicity of the new natural formicide Macex? with a battery of classical aquatic ecotoxicity tests.Material and methods
Bacteria (Aliivibrio fischeri), algae (Pseudokirchneriella subcapitata), hydra (Hydra attenuata), daphnids (Daphnia magna), and fish (Danio rerio) tests were performed in accordance with international standardized methodologies.Results
In the range of formicide concentrations tested (0.03 to 2.0?g?L?1) EC50 values varied from 0.49 to >2.0?g?L?1, with P. subcapitata being the most sensitive species and H. attenuata and D. rerio the most tolerant species to this product in aqueous solutions.Conclusions
This new formicide preparation can be classed as a product of low toxicity compared to the aquatic ecotoxicity of the most common commercialized formicides. 相似文献6.
Li Y Tang J Yu X Xu X Cheng H Wang S 《Environmental science and pollution research international》2012,19(6):2329-2343
Introduction
Trends in precipitation pH and conductivity during 1992?C2009, and in ionic compositions from January 2007 to June 2009, are reported from Lushan Mountain, one of the highest mountains in mid-east China. Annual mean pH was in the range of 4.35?C5.01 and showed a statistically very significant (P?0.01) decreasing trend with time. Annual mean conductivity showed a statistically significant (P?0.05) increasing trend, although this was not the case for non-H conductivity. Increasing rainwater acidity was mainly caused by increasing amounts of acid substances entering the rain. The trends in precipitation pH and conductivity were directly associated with energy consumption.Results and discussions
Over the period of study, Lushan Mountain received more rainfall in spring and summer. The pH values varied seasonally with winter minima. The winter multiyear seasonal mean pH was 4.35. The corresponding summer value was 4.88. SO 4 2? and NO 3 ? were the main anions, and NH 4 + and Ca2+ the main cations. The anion to cation ratio was 0.8?C1.0, and that of [SO 4 2? ] to [NO 3 ? ] was 2.4-3.0, much lower than that of the 1980s. However, sulfuric acid was still the main acid present. The ratio of [NH 4 + ] to [Ca2+] was about 1.0, suggesting that these two alkaline substances provided close acid neutralizing capacity. The ratio of [Cl?] to [Na+] was about 0.67, somewhat lower than that of natural precipitation.Conclusions
Ionic composition varied seasonally and was closely correlated to the amounts of rainfall and pollution. Trajectory analyses showed that the trajectories to Lushan Mountain could be classified in six clusters and trajectories originating from the South Sea and the areas surrounding Lushan Mountain had the greatest impacts on precipitation chemistry. 相似文献7.
Li X Zhou Q Wei S Ren W 《Environmental science and pollution research international》2012,19(5):1773-1780
Purpose
Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain.Methods
A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms.Results
The concentration of Cd in the pseudostem of welsh onions was 0.08?C0.20, 0.18?C0.41, and 0.26?C0.61?mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0?mg/kg), respectively. The significant (p?0.05) difference in the concentration of Cd in the pseudostem was observed among 25 welsh onion cultivars, but Cd contamination in soil had little influence on biomass and the contents of soluble sugar, NO 3 ? ?CN, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041?±?0.003 and 0.046?±?0.002?mg/kg FW, and 0.054?±?0.001 and 0.066?±?0.011?mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99?mg/kg, respectively.Conclusions
Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars. 相似文献8.
Murati M Oturan N Aaron JJ Dirany A Tassin B Zdravkovski Z Oturan MA 《Environmental science and pollution research international》2012,19(5):1563-1573
Introduction
The degradation and mineralization of two triketone (TRK) herbicides, including sulcotrione and mesotrione, by the electro-Fenton process (electro-Fenton using Pt anode (EF-Pt), electro-Fenton with BDD anode (EF-BDD) and anodic oxidation with BDD anode) were investigated in acidic aqueous medium.Methods
The reactivity of both herbicides toward hydroxyl radicals was found to depend on the electron-withdrawing effect of the aromatic chlorine or nitro substituents. The degradation of sulcotrione and mesotrione obeyed apparent first-order reaction kinetics, and their absolute rate constants with hydroxyl radicals at pH?3.0 were determined by the competitive kinetics method.Results and discussion
The hydroxylation absolute rate constant (k abs) values of both TRK herbicides ranged from 8.20?×?108 (sulcotrione) to 1.01?×?109 (mesotrione) L?mol?1?s?1, whereas those of the TRK main cyclic or aromatic by-products, namely cyclohexane 1,3-dione , (2-chloro-4-methylsulphonyl) benzoic acid and 4-(methylsulphonyl)-2-nitrobenzoic acid, comprised between 5.90?×?108 and 3.29?×?109?L?mol?1?s?1. The efficiency of mineralization of aqueous solutions of both TRK herbicides was evaluated in terms of total organic carbon removal. Mineralization yields of about 97?C98% were reached in optimal conditions for a 6-h electro-Fenton treatment time.Conclusions
The mineralization process steps involved the oxidative opening of the aromatic or cyclic TRK by-products, leading to the formation of short-chain carboxylic acids, and, then, of carbon dioxide and inorganic ions. 相似文献9.
Kristanti RA Kanbe M Hadibarata T Toyama T Tanaka Y Mori K 《Environmental science and pollution research international》2012,19(5):1852-1858
Introduction
The accelerated biodegradation of 3-nitrophenol (3-NP) in the rhizosphere of giant duckweed (Spirodela polyrrhiza) was investigated.Materials and methods
Biodegradation of 3-nitrophenol in the rhizosphere of a floating aquatic plant, S. polyrrhiza, was investigated by using three river water samples supplemented with 10?mg?l?1 of 3-NP. Isolation and enrichment culture of 3-NP-degrading bacteria were performed in basal salts medium containing 3-NP (50?mg?l?1). The isolated strains were physiologically and phylogenetically characterized by using an API20NE kit and 16S rRNA gene sequencing.Results and discussion
Accelerated removal of 3-NP (100%) was observed in river water samples with S. polyrrhiza compared with their removal in plant-free river water. Also, 3-NP persisted in an autoclaved solution with aseptic plants, suggesting that the accelerated 3-NP removal resulted largely from degradation by bacteria inhabiting the plant rather than from adsorption and uptake by the plant. We successfully isolated six and four strains of 3-NP-degrading bacteria from the roots of S. polyrrhiza and plant-free river water, respectively. Phylogenetic analysis based on 16S rRNA gene divided the 3-NP-degrading bacteria into two taxonomic groups: the genera Pseudomonas and Cupriavidus. The strains belonging to the genus Cupriavidus were only isolated from the roots of duckweed. All strains isolated from the roots utilized 3-NP (0.5?mM) as a sole carbon and energy source, indicating that they could have contributed to the accelerated degradation of 3-NP in the rhizosphere of S. polyrrhiza.Conclusions
The rhizoremediation using S. polyrrhiza and its rhizosphere bacteria can be an effective strategy for cleaning up the 3-NP-contaminated surface waters. 相似文献10.
Dragun Z Krasnići N Strižak Z Raspor B 《Environmental science and pollution research international》2012,19(6):2088-2095
Purpose
To examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1???g?L?1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2???g?L?1; EPCEU (Official J L 348:84, 2008)), would result in Pb accumulation in selected fish tissues.Methods
Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia?CSlovenia).Results
At the site with increased dissolved Pb in the river water, soluble gill Pb levels (17.3???g?L?1) were approximately 20 times higher compared to uncontaminated sites (0.85???g?L?1), whereas the ratio between contaminated (18.1???g?L?1) and uncontaminated sites (1.17???g?L?1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex, or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects.Conclusions
The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters. 相似文献11.
Jaiswal M Chauhan D Sankararamakrishnan N 《Environmental science and pollution research international》2012,19(6):2055-2062
Purpose
Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)??a biopolymeric waste obtained from marine industry.Methods
Synthesis and characterization of the adsorbent using different spectral techniques like Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface analyzer have been carried out. Equilibrium studies have been carried out to optimize the dose rate, pH, and the reaction time. Parathion and methyl parathion removal were also evaluated by CuCH in the batch mode. Using gas chromatography?Cmass spectrometry (GC?CMS) and FTIR studies suitable mechanism for adsorption has been suggested.Results
The particle size of the adsorbent ranged from 700 to 750?nm. The surface area was found to be 20?m2?g-1 with a pore volume of 0.11?cc?g-1. The maximum adsorption capacity of malathion by CuCH was found to be 322.6?±?3.5?mg?g-1 at an optimum pH of 2.0. Presence of copper ions enhanced the adsorption capacity of the adsorbent. The reaction was found to follow pseudo second-order kinetics with a rate constant of 0.53?g?mg-1?min-1. Evidence from FTIR indicated that copper ions form a dithionate complex with malathion during the adsorption stage. The adsorbent was found to remove malathion completely from spiked concentration of 2?mg?l-1 in the agricultural run-off samples. It was also found that CuCH removed other organophospurous pesticides like methyl parathion and parathion under prevailing conditions.Conclusions
The results indicated that CuCH could be applied for the removal of organophosphorous pesticides. 相似文献12.
Purpose
Lack of focus on the treatment of wastewaters bearing potentially hazardous pollutants like 1,1,2 trichloroethane and 1,1,2,2 tetrachloroethane in anaerobic reactors has provided an impetus to undertake this study. The objective of this exercise was to quantify the behavior of upflow anaerobic sludge blanket reactors and predict their performance based on the overall organic substrate removal.Methods
The reactors (wastewater-bearing TCA (R2), and wastewater-bearing TeCA (R3)) were operated at different hydraulic retention times (HRTs), i.e., 36, 30, 24, 18, and 12?h corresponding to food-to-mass ratios varying in the range of 0.2?C0.7?mg chemical oxygen demand (COD) mg?1 volatile suspended solids day?1. The process kinetics of substrate utilization was evaluated on the basis of experimental results, by applying three mathematical models namely first order, Grau second order, and Michaelis-Menten type kinetics.Results
The results showed that the lowering of HRT below 24?h resulted in reduced COD removal efficiencies and higher effluent pollutant concentrations in the reactors. The Grau second-order model was successfully applied to obtain the substrate utilization kinetics with high value of R 2 (>0.95). The Grau second-order substrate removal constant (K 2) was calculated as 1.12 and 7.53?day?1 for reactors R2 and R3, respectively.Conclusion
This study demonstrated the suitability of Grau second-order kinetic model over other models, for predicting the performance of reactors R2 and R3, in treating wastewaters containing chlorinated ethanes under different organic and hydraulic loading conditions. 相似文献13.
Reduction of dinitrotoluene sulfonates in TNT red water using nanoscale zerovalent iron particles 总被引:1,自引:0,他引:1
Zhu SN Liu GH Ye Z Zhao Q Xu Y 《Environmental science and pollution research international》2012,19(6):2372-2380
Purpose
This research was designed to investigate the feasibility of converting the dinitrotoluene sulfonates (DNTS) in TNT red water into the corresponding aromatic amino compounds using nanoscale zerovalent iron (NZVI).Methods
NZVI particles were simultaneously synthesized and stabilized by sodium borohydride reduction in a nondeoxygenated system. The morphology, elemental content, specific surface area, and crystal properties of the NZVI were characterized before and after the reaction by environmental scanning electron microscope; energy dispersive X-ray; Brunauer, Emmett, and Teller; and X-ray diffraction, respectively. The reduction process was conducted at pH?=?6.3 at ambient temperature. The efficiency of the NZVI-mediated DNTS reduction process was monitored by HPLC, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses.Results
The properties of the NZVI particles prepared were found to be similar to those obtained through oxygen-free preparation and inert stabilization processes. Both 2,4-DNT-3-sulfonate (2,220?mg?L?1) and 2,4-DNT-5-sulfonate (3,270?mg?L?1) in TNT red water underwent a pseudo-first-order transformation when mixed with NZVI at room temperature and near-neutral pH. Their observed rate constants were 0.11 and 0.30?min?1, respectively. Within 1?h of processing, more than 99% of DNTS was converted by NZVI-mediated reduction into the corresponding diaminotoluene sulfonates.Conclusions
NZVI can be simultaneously prepared and stabilized in a nondeoxygenated system. NZVI reduction is a highly efficient method for the conversion of DNTS into the corresponding diaminotoluene sulfonates under near-neutral pH conditions. Therefore, NZVI reduction may be useful in the treatment of TNT red water and subsequent recovery of diaminotoluene from explosive wastewater. 相似文献14.
Optimization of nitrate reduction by EDTA catalyzed zero-valent bimetallic nanoparticles in aqueous medium 总被引:2,自引:0,他引:2
Kunwar P. Singh Arun K. Singh Shikha Gupta 《Environmental science and pollution research international》2012,19(9):3914-3924
The present study aims to investigate the EDTA catalyzed reduction of nitrate (NO 3 ? ) by zero-valent bimetallic (Fe?CAg) nanoparticles (ZVBMNPs) in aqueous medium and to enumerate the effect of temperature, solution pH, ZVBMNPs dose and EDTA concentration on NO 3 ? reduction. Batch experimental data were generated using a four-factor Box?CBehnken design. Optimization modeling was performed using the response surface method for maximizing the reduction of NO 3 ? by ZVBMNPs. Significance of the independent variables and their interactions were tested by the analysis of variance and t test statistics. The model predicted maximum reduction capacity (340.15?mg?g?1 NO 3 ? ) under the optimum conditions of temperature, 60?°C; pH?4; dose, 1.0?g?l?1; and EDTA concentration, 2.0?mmol?l?1 was very close to the experimental value (338.62?mg?g?1) and about 16?% higher than the experimentally determined capacity (291.32?mg?g?1). Study demonstrated that ZVBMNPs had higher reduction efficiency than Fe0 nanoparticles for NO 3 ? . EDTA significantly enhanced the NO 3 ? reduction by ZVBMNPs. The EDTA catalyzed reduction of NO 3 ? by ZVBMNPs can be employed for the effective decontamination of water. 相似文献
15.
Peuravuori J 《Environmental science and pollution research international》2012,19(6):2259-2270
Purpose
This study contains some new findings connected to the photolysis of the drug paracetamol (hereinafter APAP) especially in light of estimating natural conditions, and it will offer information to better evaluate environmental problems connected with this widely used analgesic agent. Only a few studies, so far, have focussed on the photodegradation process of APAP in the natural environment, and the question about the role of the colored/chromophoric dissolved organic matter (CDOM) and nitrate (NO 3 ? ) as photoinductors is almost open.Methods
APAP dissolved in freshwater and pure laboratory water in the presence and absence of CDOM and NO 3 ? ions was irradiated using weak-energy photon energies simulating natural conditions.Results
CDOM and NO 3 ? as photoinductors produced only the slow phototransformation of APAP under weak energy radiation, and APAP seemed to be practically resistant to direct photolysis under weak radiant energies available in natural conditions. The estimated reaction efficiencies, in addition to half-lives, speak for that NO 3 ? and CDOM do not act as quite independent photoinductors but their effect in conjunction (CDOM?CNO 3 ? ?Cwater) is stronger than the separate ones. The principal phototransformation intermediates of APAP were mono-hydroxy derivatives, depending on available photon energies formed via ortho- or meta-hydroxylation, possessing substantial power of resistance to further specific transformation reactions.Conclusions
The estimated half-life of the phototransformation of APAP in the natural aqueous environment and in the presence of suitable photoinductors will be about 30?days or more. 相似文献16.
Bioremediation of chromium by novel strains Enterobacter aerogenes T2 and Acinetobacter sp. PD 12 S2
Purpose
This study had an objective to identify the most potent chromium-resistant bacteria isolated from tannery effluent and apply them for bioremediation of chromium in tannery effluents.Methods
Two such strains (previously characterized and identified by us)??Enterobacter aerogenes (NCBI GenBank USA Accession no. GU265554) and Acinetobacter sp. PD 12 (NCBI GenBank USA Accession no. GU084179)??showed powerful chromium resistivity and bioremediation capabilities among many stains isolated from tannery waste. Parameters such as pH, concentration of hexavalent chromium or Cr (VI), and inoculum volume were varied to observe optimum bioconversion and bioaccumulation of Cr (VI) when the said strains were grown in M9 minimal salt media. E. aerogenes was used to remediate chromium from tannery effluents in a laboratory level experiment.Results
Observation by Scanning Electron Microscope and chromium peak in Energy Dispersive X-ray Spectroscopic microanalysis revealed that E. aerogenes helped remediate a moderate amount of Cr (VI) (8?C16?mg?L?1) over a wide range of pH values at 35?C37°C (within 26.05?h). High inoculum percentage of Acinetobacter sp. PD 12 also enabled bioremediation of 8?C16?mg?L?1 of Cr (VI) over a wide range of temperature (25?C37°C), mainly at pH?7 (within 63.28?h). The experiment with real tannery effluent gave very encouraging results.Conclusion
The strain E. aerogenes can be used in bioremediation of Cr (VI) since it could work in actual environmental conditions with extraordinarily high capacity. 相似文献17.
C. Montero-Ocampo A. Gago G. Abadias B. Gombert N. Alonso-Vante 《Environmental science and pollution research international》2012,19(9):3751-3762
Introduction
In this work, we report in situ studies of UV photoelectrocatalytic discoloration of a dye (indigo carmine) by a TiO2 thin film in a microreactor to demonstrate the driving force of the applied electrode potential and the dye flow rate toward dye discoloration kinetics.Methods
TiO2 65-nm-thick thin films were deposited by PVD magnetron sputtering technique on a conducting glass substrate of fluorinated tin oxide. A microreactor to measure the discoloration rate, the electrode potential, and the photocurrent in situ, was developed. The dye solutions, before and after measurements in the microreactor, were analyzed by Raman spectroscopy.Results
The annealed TiO2 thin films had anatase structure with preferential orientation (101). The discoloration rate of the dye increased with the applied potential to TiO2 electrode. Further, acceleration of the photocatalytic reaction was achieved by utilizing dye flow recirculation to the microreactor. In both cases the photoelectrochemical/photocatalytic discoloration kinetics of the dye follows the Langmuir?CHinshelwood model, with first-order kinetics.Conclusions
The feasibility of dye discoloration on TiO2 thin film electrodes, prepared by magnetron sputtering using a flow microreactor system, has been clearly demonstrated. The discoloration rate is enhanced by applying a positive potential (E AP) and/or increasing the flow rate. The fastest discoloration and shortest irradiation time (50?min) produced 80% discoloration with an external anodic potential of 0.931?V and a flow rate of 12.2?mL?min?1. 相似文献18.
The effects of cerium on the growth and some antioxidant metabolisms in rice seedlings 总被引:2,自引:1,他引:1
Liu D Wang X Lin Y Chen Z Xu H Wang L 《Environmental science and pollution research international》2012,19(8):3282-3291
Introduction
The aims of the present study are to investigate the effects of Ce3+ on the growth and some antioxidant metabolisms in rice seedlings (Oryza sativa L. cv Shengdao 16).Materials and methods
The rice was treated with 0, 0.05, 0.1, 0.5, 1.0, and 1.5?mM Ce3+, respectively. The growth index of rice was measured. The chlorophyll content; catalase, superoxide dismutase, and peroxidase activities; and the level of hydrogen peroxide (H2O2), superoxide anion (O 2 ·? ), and malondialdehyde were assayed. The accumulation of Ce3+ and the uptake of mineral nutrition elements were analyzed with ICP-SF-MS.Results and discussion
Hormetic effects of Ce3+ on the growth and some antioxidant metabolisms were found in the roots and shoots of rice. The roots can accumulate a much higher content of Ce3+ than shoots and Ce3+ mainly located in the cell wall of roots. Moreover, the uptake of K, Mg, Ca, Na, Fe, Mn, Zn, Cu, and Mo in the roots and shoots was affected with the exposure of different Ce3+ treatments, which indicated that Ce3+ affected the nutritional status of roots and shoots and further affected the growth of rice.Conclusion
The appropriate amount of Ce3+ improved the defense system and growth of rice. The roots can accumulate a much higher content of Ce3+ than shoots. Moreover, the uptake of K, Mg, Ca, Na, Fe, Mn, Zn, Cu, and Mo in the roots and shoots was affected with the exposure of different Ce3+ treatments. 相似文献19.
J Chen X Zhou Y Zhang Y Zi Y Qian H Gao S Lin 《Environmental science and pollution research international》2011,19(7):2528-2536
Purpose
The interaction between triclosan (TCS) and human serum albumin (HSA) was investigated in order to obtain the binding mechanism, binding constant, the type of binding force, the binding distance between the donor and acceptor, and the effect of TCS on the conformation change of HSA.Methods
A HSA solution was added to the quartz cell and then titrated by successive addition of TCS. The fluorescence quenching spectra and synchronous spectra were recorded with the excitation and emission slits of the passage of band set at 10 and 20 nm. Three-dimensional fluorescence spectra of HSA were recorded before and after the addition of TCS. The capillary electrophoresis was conducted with the pressure injection mode at 0.5 psi for 5 s, separation under 25 kV, and detection at 214 nm.Results
Fluorescence data indicated the fluorescence quenching of HSA by TCS was static quenching, and the quenching constants (K a ) were 1.14?×?105, 8.75?×?104, 6.67?×?104, and 5.00?×?104 at 293, 298, 303, and 309 K, respectively. The thermodynamic parameters, enthalpy change (??H) and entropy change (??S) for the interaction were calculated to be ?37.9 kJ mol?1 and 32.6 J?mol?1 K?1. The binding distance between TCS and tryptophan residues of HSA was obtained to be 1.81 nm according to F??rster nonradioactive energy transfer theory. The UV-Vis absorption spectroscopy, the synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and circular dichroism spectroscopy revealed the alterations of HSA secondary structure in the presence of TCS. Finally, the interaction between TCS and HSA was further confirmed by capillary electrophoresis.Conclusions
TCS was bound to HSA to form the TCS-HSA complex, with the binding distance of 1.81 nm. Hydrophobic interaction and hydrogen bond were dominated in the binding. TCS could change the secondary conformation of HSA. This work provides an insight into noncovalent interaction between emerging pollutants and protein, helping to elucidate the toxic mechanism of such pollutants. 相似文献20.
Garcia-Käufer M Haddad T Bergheim M Gminski R Gupta P Mathur N Kümmerer K Mersch-Sundermann V 《Environmental science and pollution research international》2012,19(5):1719-1727