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1.
Zhang Y Jiang Z Cao B Hu M Wang Z Dong X 《Environmental science and pollution research international》2011,19(7):2951-2958
Introduction
A plasmid named pDNS10 was detected from an atrazine-degrading strain Arthrobacter sp. DNS10 which has been isolated previously in our laboratory.Materials and methods
In this paper, a special plasmid-detecting method and drop assays experiments were mainly used to achieve research goals.Results and discussion
pDNS10 exhibited an excellent stability because it also could be detected even when the strain DNS10 has been subcultured under nonselective conditions for eight times. Over a 48-h incubation period, the OD600 of samples inoculated with strain DNS10 and strain DNS10-ST (both of them contained pDNS10) were 0.31 ± 0.042 and 0.305 ± 0.034, respectively ,whereas the OD600 of samples inoculated strain without pDNS10 (strain DNS10-PE) was only 0.138 ± 0.018. No atrazine was detected in the inoculated strain DNS10 and strain DNS10-ST samples at this period. Contrarily, the atrazine-degrading rate of strain DNS10-PE was only 5.23 ± 0.71%. Furthermore, both the two types of strains containing pDNS10 confirmed the presence of known degrading genes such as trzN, atzB, and atzC. It suggests that pDNS10 is an atrazine catabolic plasmid. In drop assays experiments, the wild-type strain DNS10 cells were chemotactically attracted to atrazine, whereas strain DNS10-PE showed no chemotaxis to atrazine and hydroxyatrazine. There was some relationship between atrazine degradation and the chemotactic response towards atrazine in strain DNS10.Conclusions
The biochemical characteristics of pDNS10 and the chemotaxis characteristics of strain DNS10 could help us in better understanding of the mechanism of atrazine degradation by strain DNS10. 相似文献2.
Pamornrat Kueseng Mathieu L. Noir Bo Mattiasson Panote Thavarungkul Proespichaya Kanatharana 《Journal of environmental science and health. Part. B》2013,48(8):772-780
A molecularly imprinted polymer (MIP) for atrazine was synthesized by non-covalent method. The binding capacity of MIP was 1.00 mg g? 1 polymer. The selectivity and recovery were investigated with various pesticides which are mostly, found in the environment, for both similar and different chemical structure of atrazine. The competitive recognition between atrazine and structurally similar compounds was evaluated and it was found that the system provided highest recovery and selectivity for atrazine while low recovery and selectivity were obtained for the other compounds. The highest recovery was obtained from MIP compared with non-imprinted polymer (NIP), a commercial C18 and a granular activated carbon (GAC) sorbent. The method provided high recoveries ranged from 94 to 99% at two spiked levels with relative standard deviations less than 2%. The lower detection limit of the method was 80 ng L? 1. This method was successfully applied for analysis of environmental water samples. 相似文献
3.
Microbial structure and chemical components of aerosols caused by rotating brushes in a wastewater treatment plant 总被引:1,自引:0,他引:1
Yunping Han Lin Li Junxin Liu Mengzhu Zhang 《Environmental science and pollution research international》2012,19(9):4097-4108
Purpose
Bacterial community structure and the chemical components in aerosols caused by rotating brushes in an Orbal oxidation ditch were assessed in a Beijing municipal wastewater treatment plant.Methods
Air samples were collected at different distances from the aerosol-generating rotating brushes. Molecular culture-independent methods were used to characterize the community structure of the airborne bacteria in each sample regardless of cell culturability. A clone library of 16S rDNA directly amplified from air DNA of each sample was constructed and sequenced to analyze the community composition and diversity. Insoluble particles and water-soluble ions emitted with microorganisms in aerosols were analysis by a scanning electron microscope together with energy dispersive X-ray spectroscopy and ion chromatogram analyzer.Results
In total, most of the identified bacteria were Proteobacteria. The majority of sequences near the rotating brushes (the main source of the bioaerosols) were Proteobacteria (62.97 %) with ??-(18.52 %) and ??-(44.45?%) subgroups and Bacteroidetes (29.63 %). Complex patterns were observed for each sampling location, suggesting a highly diverse community structure, comparable to that found in water in the Orbal oxidation ditch. Accompany with microorganisms, 46.36???g/m3 of SO 4 2? , 29.35???g/m3 of Cl?, 21.51???g/m3 of NO 3 ? , 19.76???g/m3 of NH 4 + , 11.42???g/m3 of PO 4 3? , 6.18???g/m3 of NO 2 ? , and elements of Mg, Cl, K, Na, Fe, S, and P were detected from the air near the aerosols source.Conclusions
Differences in the structure of the bacterial communities and chemical components in the aerosols observed between sampling sites indicated important site-related variability. The composition of microorganisms in water was one of the most important sources of bacterial communities in bioaerosols. Chemical components in bioaerosols may provide a media for airborne microorganism attachment, as well as a suitable microenvironment for their growth and survival in the air. This study will be benefit for the formulation of pollution standards, especially for aerosols, that take into account plant workers?? health. 相似文献4.
Karthikeyan S Ezhil Priya M Boopathy R Velan M Mandal AB Sekaran G 《Environmental science and pollution research international》2012,19(5):1828-1840
Background, aim, scope
Treatment of wastewater has become significant with the declining water resources. The presence of recalcitrant organics is the major issue in meeting the pollution control board norms in India. The theme of the present investigation was on partial or complete removal of pollutants or their transformation into less toxic and more biodegradable products by heterogeneous Fenton oxidation process using mesoporous activated carbon (MAC) as the catalyst.Materials and methods
Ferrous sulfate (FeSO4·7H2O), sulfuric acid (36?N, specific gravity 1.81, 98% purity), hydrogen peroxide (50% v/v) and all other chemicals used in this study were of analytical grade (Merck). Two reactors, each of height 50?cm and diameter 6?cm, were fabricated with PVC while one reactor was packed with MAC of mass 150?g and other without MAC served as control.Results and discussion
The oxidation process was presented with kinetic and thermodynamic constants for the removal of COD, BOD, and TOC from the wastewater. The activation energy (Ea) for homogeneous and heterogeneous Fenton oxidation processes were 44.79 and 25.89?kJ/mol, respectively. The thermodynamic parameters ??G, ??H, and ??S were calculated for the oxidation processes using Van??t Hoff equation. Furthermore, the degradation of organics was confirmed through FTIR and UV?Cvisible spectroscopy, and cyclic voltammetry.Conclusions
The heterocatalytic Fenton oxidation process efficiently increased the biodegradability index (BOD/COD) of the tannery effluent. The optimized conditions for the heterocatalytic Fenton oxidation of organics in tannery effluent were pH 3.5, reaction time?C4?h, and H2O2/FeSO4·7H2O in the molar ratio of 2:1. 相似文献5.
?árka Pau?ová Josef Krysa Jaromír Jirkovsky Gilles Mailhot Vanessa Prevot 《Environmental science and pollution research international》2012,19(9):3709-3718
Introduction
Efficient immobilization of TiO2 nanoparticles on the surface of Mg2Al-LDH nanosheets was performed by delamination/restacking process.Experimental part
The structural and textural properties of as-prepared nanocomposite were deeply analyzed using different solid-state characterization techniques such as: X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopies, chemical analysis, X-ray photoelecton spectroscopy, N2 adsorption?Cdesorption, and electronic microscopy.Results and discussion
The photocatalytic properties of immobilized TiO2 nanoparticles on Mg2Al were investigated using the photodegradation of two model pollutants: Orange II and 4-chlorophenol, and compared with pure colloidal TiO2 solution.Conclusion
It appears that Orange II photodegradation was systematically faster and more efficient than 4-chlorophenol photodegradation regardless of the medium pH. Moreover under slightly basic conditions, even if the TiO2 photocatalytic efficiency decreases, photodegradation performed in presence of easily recovered TiO2/Mg2Al1.5 nanocomposite gives rise to comparable or better results than pure TiO2. 相似文献6.
Alqudami A Alhemiary NA Munassar S 《Environmental science and pollution research international》2011,19(7):2832-2841
Purpose
This work aimed at investigating the adsorption of lead and cadmium onto Fe and Ag nanoparticles for use as a water contaminant removal agent as a function of particle type, sorbent concentration, and contact time.Methods
Fe and Ag spherical nanoparticles were prepared in water by the lab-made electro-exploding wire (EEW) system and were investigated for their structure properties. Adsorption experiments were carried out at room temperature and pH 8.3 water solutions.Results
The removal/adsorption of both Pb(II) and Cd(II) ions was found to be dependent on adsorbent dosage and contact time. Pb(II) adsorption onto Fe and Ag nanoparticles showed more or less similar efficiency and behavior. The kinetic data for the adsorption process obeyed pseudo second-order rate equations. The calculated equilibrium adsorption capacities (q e) were 813 and 800 mg/g for Pb sorption onto Fe and Ag nanoparticles, respectively. Cd(II) ion adsorption onto Fe nanoparticles obeyed pseudo second-order rate equations with q e equal to 242 mg/g, while their adsorption onto Ag nanoparticles obeyed pseudo first-order rate equations with q e of 794 mg/g. The calculated q es are in quite agreement with the experimental values. The removal/uptake mechanisms of metal ions involved interaction between the metal ion and the oxide/hydroxyl layer around the spherical metallic core of the nanoparticle in water medium.Conclusion
Fe and Ag nanoparticles prepared using the EEW technique exhibited high potentials for the removal of metal ions from water with very high adsorption capacities, suggesting that the EEW technique can be enlarged to generate nanoparticles with large quantities for field or site water purification. 相似文献7.
Introduction
Titanium dioxide (TiO2) nanoparticle powders have been extensively studied to quickly photodegrade some organic pollutants; however, the effect of the particle size of TiO2 nanoparticle aggregates on degradation remains unclear because microscale aggregates form once the nanoparticle powders enter into water.Methods
The degradation of azo dye by different particle sizes of TiO2 nanoparticle aggregates controlled by NaCl concentrations was investigated to evaluate the particle size effect. Removal reactions of reactive black 5 (RB5) with TiO2 nanoparticles followed pseudo-first-order kinetics.Results
The increase of TiO2 dosage from 40 to 70?mg/L enhanced the degradation. At doses around 100?mg/L TiO2, degradation rates decreased which could be the result of poor UV light transmittance at high-particle concentrations. At average particle sizes of TiO2 nanopowders less than around 500?nm, the degradation rates increased with decreasing particle size. As the average particle size exceeded 500?nm, the degradation rates were not significantly changed.Conclusions
For the complete degradation experiments, the mineralization rates of total organic carbon disappearance are generally following the RB5 decolorization kinetic trend. These findings can facilitate the application of TiO2 nanoparticles to the design of photodegradation treatments for wastewater. 相似文献8.
Teixeira S Delerue-Matos C Santos L 《Environmental science and pollution research international》2012,19(8):3096-3106
Purpose
The sorption of sulfamethoxazole, a frequently detected pharmaceutical compound in the environment, onto walnut shells was evaluated.Methods
The sorption proprieties of the raw sorbent were chemically modified and two additional samples were obtained, respectively HCl and NaOH treated. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric (TG/DTG) techniques were applied to investigate the effect of the chemical treatments on the shell surface morphology and chemistry. Sorption experiments to investigate the pH effect on the process were carried out between pH?2 and 8.Results
The chemical treatment did not substantially alter the structure of the sorbent (physical and textural characteristics) but modified the surface chemistry of the sorbent (acid?Cbase properties, point of zero charge??pHpzc). The solution pH influences both the sorbent??s surface charge and sulfamethoxazole speciation. The best removal efficiencies were obtained for lower pH values where the neutral and cationic sulfamethoxazole forms are present in the solution. Langmuir and Freundlich isotherms were applied to the experimental adsorption data for sulfamethoxazole sorption at pH?2, 4, and 7 onto raw walnut shell. No statistical difference was found between the two models except for the pH?2 experimental data to which the Freundlich model fitted better.Conclusion
Sorption of sulfamethoxazole was found to be highly pH dependent in the entire pH range studied and for both raw and treated sorbent. 相似文献9.
Purpose
Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have emerged as contaminants of environmental concerns because they pose potential risks to human and animal health. The purpose of this study was to investigate the in vitro metabolism of OH-PBDEs and their potential inhibition against 17??-estradiol (E2) metabolism.Methods
Rat liver microsomes were used as a source of P450 enzymes in an in vitro metabolism study of OH-PBDEs. Inhibition of E2 metabolism and kinetic study were performed by incubating with rat liver microsomes in the presence of OH-PBDEs.Results
The obtained data clearly demonstrated that OH-PBDEs, especially those congeners with lower bromination, could be metabolized to bromophenol and diOH-PBDEs. The less metabolic rate of OH-PBDEs was observed with the increasing number of bromine substituents. OH-PBDEs with hydroxyl group and bromine adjacent to the ether bridge showed faster metabolic rates. In addition, the results showed non-competitive inhibition of E2 metabolism by OH-PBDEs with IC50 values in the range from 13.7 to 55.2???M. The most potent OH-PBDE inhibitor was found to be 3??-OH-BDE-100. The inhibitory potencies for OH-PBDEs were significantly higher than those of parent PBDE and methoxylated metabolites, providing the evidence that PBDEs exerted estrogenic activity in part by their hydroxylated metabolites.Conclusions
OH-PBDEs exhibited large differences in their capacity to be metabolized and to inhibit E2 metabolism in rat liver microsomes. The finding might increase our understanding of healthy risk associated with PBDEs in human and wildlife. 相似文献10.
Silva E Mendes MP Ribeiro L Cerejeira MJ 《Environmental science and pollution research international》2011,19(7):2667-2680
Purpose
To assess groundwater exposure to pesticides, in agricultural areas of ??Ribatejo?? region (Portugal), and the influence of some key factors in that exposure, field, laboratory and modelling studies were carried out.Methods
The study was performed in maize, potato, sugar beet, tomato and vegetables agricultural areas, located in a shallow aquifer, with pesticides use and, in most cases, with irrigation practices. Pesticides used in the studied agricultural areas and having leaching potential were selected, being considered also other pesticides included in priority lists, defined in Europe. Evaluation of groundwater exposure to pesticides was carried out by successively: (1) groundwater sampling in seven campaigns over the period 2004?C2006; (2) pesticide analysis [including isolation and concentration from the groundwater samples and further determination by gas chromatography?Cmass spectrometry (GC?CMS) of 14 herbicides, four insecticides and two metabolites]; and (3) analysis and discussion of the results by applying joint correspondence analysis (JCA).Results
From the 20 pesticides and metabolites selected for the study, 11 were found in groundwater. Pesticides and metabolites most frequently detected were atrazine, alachlor, metolachlor, desethylatrazine, ethofumesate, ??-endosulfan, metribuzine, lindane and ??-endosulfan. The results showed that groundwater exposure to pesticides is influenced by local factors??either environmental or agricultural, as precipitation, soil, geology, crops and irrigation practices. Spring and autumn were more associated with the detection of pesticides being more likely to observe mixtures of these compounds in a groundwater sample in these transition seasons.Conclusions
This work evidences the importance of models, which evaluate pesticides environmental behaviour, namely their water contamination potential (as Mackay multicompartimental fugacity model) and, specially, groundwater contamination potential (as GUS and Bacci and Gaggi leaching indices), in pesticide selection. Moreover, it reveals the importance to adapt proper statistical methods according to level of left-censored data. Using JCA was still possible to establish relations between pesticides and their temporal trend in a case study where there were more than 80% of data censored. This study will contribute to the Tagus river basin management plan with information on the patterns of pesticide occurrence in the alluvial aquifer system. 相似文献11.
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
12.
Nordén M Westman O Venizelos N Engwall M 《Environmental science and pollution research international》2012,19(5):1859-1863
Purpose
Perfluorooctane sulfonate (PFOS) belongs to a group of chemicals called perfluoroalkyl acids that have been extensively used in various applications such as stain and oil resistant treatments for fabrics, fire-fighting foams, and insecticides. These chemicals present an environmental and health risk being present in many samples both in wildlife and humans. In this study, we investigate the effect of PFOS on fatty acid ??-oxidation in developing chicken embryos.Methods
Fertilized chicken eggs were exposed in ovo to PFOS at day?4 of incubation. On day?10, the eggs were dissected and livers were incubated in vitro with 3H-palmitic acid for 2?h. The media were collected, and after clean up, the amount of tritiated water was measured with liquid scintillation counting to determine the rate of palmitic acid ??-oxidation.Results
PFOS was found to induce fatty acid ??-oxidation at doses starting from a lowest observed effect level (LOEL) of 0.1???g/g egg weight. Maximum induction of 77?% compared to control was seen at 0.3???g/g.Conclusions
The administered doses in which effects are seen are around and even lower than the levels that can be found in wild populations of birds. General population human levels are a factor of two to three times lower than the LOEL value of this study. The environmental contamination of PFOS therefore presents a possibility of effects in wild populations of birds. 相似文献13.
Xu L Chen X Chen J Zhang F He C Du K Wang Y 《Environmental science and pollution research international》2012,19(5):1443-1453
Background
PM10 aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM10 mass concentrations and chemical compositions were determined.Methods
Water-soluble inorganic ions (Cl?, NO 3 ? , SO 4 2? , NH 4 + , K+, Na+, Ca2+, and Mg2+), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively.Results
PM10 mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO 4 2? , NO 3 ? , and NH 4 + showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM10. The sum of individually measured components accounted for 86.9?C97.7% of the total measured PM10 concentration, and the discrepancy was larger in urban area than in urban background area.Conclusion
According to the principal component analysis?Cmultivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM10 particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM10, respectively. 相似文献14.
Adsorption of Remazol Red 198 onto magnetic N-lauryl chitosan particles: equilibrium, kinetics, reuse and factorial design 总被引:1,自引:0,他引:1
Debrassi A Baccarin T Demarchi CA Nedelko N Ślawska-Waniewska A Dłużewski P Bilska M Rodrigues CA 《Environmental science and pollution research international》2012,19(5):1594-1604
Purpose
The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field.Methods
Magnetic N-lauryl chitosan (L-Cht/??-Fe2O3) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/??-Fe2O3. The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 23 factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle.Results
The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir?CFreundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267?mg?g?1. The material can be reused, but with a decrease in the amount of adsorbed dye.Conclusions
L-Cht/??-Fe2O3 is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents. 相似文献15.
Zaharia C 《Environmental science and pollution research international》2012,19(6):2448-2455
Introduction
The paper analyses the environment pollution state in different case studies of economic activities (i.e. co-generation electric and thermal power production, iron profile manufacturing, cement processing, waste landfilling, and wood furniture manufacturing), evaluating mainly the environmental cumulative impacts (e.g. cumulative impact against the health of the environment and different life forms).Materials and methods
The status of the environment (air, water resources, soil, and noise) is analysed with respect to discharges such as gaseous discharges in the air, final effluents discharged in natural receiving basins or sewerage system, and discharges onto the soil together with the principal pollutants expressed by different environmental indicators corresponding to each specific productive activity. The alternative methodology of global pollution index (I GP * ) for quantification of environmental impacts is applied.Results and discussion
Environmental data analysis permits the identification of potential impact, prediction of significant impact, and evaluation of cumulative impact on a commensurate scale by evaluation scores (ESi) for discharge quality, and global effect to the environment pollution state by calculation of the global pollution index (I GP * ).Conclusions
The I GP * values for each productive unit (i.e. 1.664?C2.414) correspond to an ??environment modified by industrial/economic activity within admissible limits, having potential of generating discomfort effects??. The evaluation results are significant in view of future development of each productive unit and sustain the economic production in terms of environment protection with respect to a preventive environment protection scheme and continuous measures of pollution control. 相似文献16.
Lee J Kim J Kim S Im G Lee S Jeon EC 《Environmental science and pollution research international》2011,19(7):2722-2727
Introduction
Korea has been making efforts to reduce greenhouse gas (GHG) emissions, including a voluntary commitment to the target of a 30% reduction, based on business-as-usual of the total GHG emission volume, by 2020; 2006 IPCC Guidelines provided default values, applying country-specific emission factors was recommended when estimating national greenhouse gas emissions.Results and discussion
This study focused on anthracite produced in Korea in order to provide basic data for developing country-specific emission factor. This study has estimated CO2 emission factors to use worksheet of which five steps consisted according to the fuel analysis method.Conclusion
As a result, the average of net colorific value for 3 years (2007??2009) was 4,519 kcal/kg, and the CO2 emission factor was calculated to be 111,446 kg/TJ, which is about 11.8% lower than the 2006 IPCC guidelines default value, and about 7.9% higher than the US EPA emission factor. 相似文献17.
Raud M Tutt M Jõgi E Kikas T 《Environmental science and pollution research international》2011,19(7):3039-3045
Introduction
Two semi-specific microbial biosensors were constructed for the analysis of biochemical oxygen demand (BOD) in high-cellulose-content pulp and paper industry wastewaters. The biosensors were based on living cells of Bacillus subtilis and Paenibacillus sp. immobilized in an agarose gel matrix. Semi-specific microorganisms were isolated from various samples (decaying sawdust and rabbit manure) and were chosen based on their ability to assimilate cellulose.Materials &; methods
The biosensors were calibrated with the Organization for Economic Cooperation and Development synthetic wastewater, and measurements with different wastewaters were conducted.Results
The response time of biosensors using the steady-state method was 20?C25 min, and the service life of immobilized microorganisms was 96 days. Detection limit was 5 mg/l of BOD7 while linear ranges extended up to 55 and 50 mg/l of the BOD7 for B. subtilis- and Paenibacillus sp.-based biosensors, respectively. Repeatability and reproducibility of both biosensors were within the limits set by APHA??less than 15.4%. In comparison, both biosensors overestimated the BOD7 values in paper mill wastewaters and underestimated the BOD7 in aspen pulp mill wastewater.Conclusions
The semi-specific biosensors are suitable for the estimation of organic pollution derived from cellulose, while the detection of pollution derived from tannins and lignins was minor. Better results in terms of accuracy and repeatability were gained with Paenibacillus sp. biosensor. 相似文献18.
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19.
Background
In this paper, batch removal of hexavalent chromium from aqueous solutions by Araucaria heterophylla leaves was investigated. The batch experiments were conducted to study the adsorption of metal species and effect of different pH, contact time, metal concentration, biosorbent concentration, and adsorption capacity.Method
Freundlich and Langmuir??s isotherm model were used to describe the adsorption behavior, and the experimental results fitted Freundlich model well.Results
The adsorption efficiency observed for all chromium concentrations, i.e., 1, 3, 5, and 10?mg/L was 100% and the equilibrium was achieved in 30?min for 1 and 3?mg/L, whereas for 5 and 10?mg/L, it was less than 60?min. FTIR spectra was taken to identify functional groups involved in the biosorption.Conclusion
Thus, Araucaria leaves can be considered as one of the cheap and efficient biosorbent for toxic hexavalent chromium removal from natural or wastewaters. 相似文献20.
Li WW Sheng GP Zeng RJ Liu XW Yu HQ 《Environmental science and pollution research international》2012,19(5):1422-1431