Uticaj meteoroloških parametara na koncentraciju SO2 u Obrenovcu, Srbija

In this paper, the impacts of some meteorological parameters on the SO2 concentrations in the City of Obrenovac are presented. The City of Obrenovac is located in the north-west part of Serbia on the banks of the River Sava. The observed source emission, the power plants TENT A and B are situated on the bank of the Sava River in the vicinity of Obrenovac. During the period from January to November 2006, the concentrations of sulfur dioxide in the air at 4 monitoring sites in Obrenovac were measured. It was noticed that the maximal measured daily concentrations of sulfur dioxide ranged from 1 μg m-3 (16th November, 2006) to 98 μg m-3 (29th January 2006) and lie under the maximal allowed concentration value according to the Serbian Law on Environmental Protection. The measured sulfur dioxide concentrations mostly showed characteristics usual for a daily acidification sulfur dioxide cycle, excluding the specificities influenced by the measuring site itself. Sulfur dioxide transport was recorded at increased wind speeds, primarily from the southeast direction. Based on the impact of meteorological parameters on the sulfur dioxide concentration, a validation of the monitoring sites was also performed from the aspect of their representivity.U radu su predstavljeni rezultati monitoringa koncentracije SO2 u vazduhu u Obrenovcu koji se nalazi na severozapadu Srbije na obalama reke Save. Posmatran je uticaj meteoroloških parametara na koncentraciju SO2 emitovanog iz termoelektrana TENT A i B koji se smatraju najvećim izvorima emisije. U periodu od januara do novembra 2006. godine praćene su koncentracije sumpor-dioksida u vazduhu na 4 merna mesta lokalizovana na različitim udaljenostima od izvora emisije. Maksimalne izmerene dnevne koncentracije sumpor-dioksida su se kretale od 1 μg m-3 (16. novembra, 2006) do 24 μg m-3 (29. januara, 2006). Izmerene promene koncentracija sumpor-dioksida uglavnom pokazuju uobičajene karakteristike dnevne acidifikacije ciklusa uz razlike koje potiču od osobenosti mernih mesta. Transport sumpor-dioksida zabeležen je pri pojačanom vetru prvenstveno iz jugoistočnog pravca. Na osnovu korelacionih odnosa između koncentracije sumpor-dioksida i odgovarajućih meteroloških parametara izvršena je karakterizacija mernih mesta u pogledu njihove reprezentativnosti za merenje sumpor-dioksida

Uticaj meteoroloških parametara na koncentraciju SO2 u Obrenovcu, Srbija

In this paper, the impacts of some meteorological parameters on the SO2 concentrations in the City of Obrenovac are presented. The City of Obrenovac is located in the north-west part of Serbia on the banks of the River Sava. The observed source emission, the power plants TENT A and B are situated on the bank of the Sava River in the vicinity of Obrenovac. During the period from January to November 2006, the concentrations of sulfur dioxide in the air at 4 monitoring sites in Obrenovac were measured. It was noticed that the maximal measured daily concentrations of sulfur dioxide ranged from 1 μg m-3 (16th November, 2006) to 98 μg m-3 (29th January 2006) and lie under the maximal allowed concentration value according to the Serbian Law on Environmental Protection. The measured sulfur dioxide concentrations mostly showed characteristics usual for a daily acidification sulfur dioxide cycle, excluding the specificities influenced by the measuring site itself. Sulfur dioxide transport was recorded at increased wind speeds, primarily from the southeast direction. Based on the impact of meteorological parameters on the sulfur dioxide concentration, a validation of the monitoring sites was also performed from the aspect of their representivity.U radu su predstavljeni rezultati monitoringa koncentracije SO2 u vazduhu u Obrenovcu koji se nalazi na severozapadu Srbije na obalama reke Save. Posmatran je uticaj meteoroloških parametara na koncentraciju SO2 emitovanog iz termoelektrana TENT A i B koji se smatraju najvećim izvorima emisije. U periodu od januara do novembra 2006. godine praćene su koncentracije sumpor-dioksida u vazduhu na 4 merna mesta lokalizovana na različitim udaljenostima od izvora emisije. Maksimalne izmerene dnevne koncentracije sumpor-dioksida su se kretale od 1 μg m-3 (16. novembra, 2006) do 24 μg m-3 (29. januara, 2006). Izmerene promene koncentracija sumpor-dioksida uglavnom pokazuju uobičajene karakteristike dnevne acidifikacije ciklusa uz razlike koje potiču od osobenosti mernih mesta. Transport sumpor-dioksida zabeležen je pri pojačanom vetru prvenstveno iz jugoistočnog pravca. Na osnovu korelacionih odnosa između koncentracije sumpor-dioksida i odgovarajućih meteroloških parametara izvršena je karakterizacija mernih mesta u pogledu njihove reprezentativnosti za merenje sumpor-dioksida

Safe trapping of Cs radionuclides in sintered matrix of zeolites

Cesium aluminosilicate phases are of the great interest as possible host for Cs immobilization in radioactive waste management. The possibility to use zeolite as a host material for radioactive Cs immobilization was investigated. Cs-exchanged forms of clinoptilolite and 13X which were prepared by ion-exchange treatment were compacted. The powders compacts of exchanged zeolites were thermally treated at 1200 °C. The XRD analysis showed that Cs was successfully immobilized after heat treatment by formation of stable cesium-aluminosilicate ceramic forms. Thermal and mechanical properties of the sintered samples were investigated. From the perspective of these characteristics, Cs-exchanged zeolite (clinoptilolite and 13 X) can be considered as a potential material for safe waste disposal

Surface characterisation of mechanochemicaly activated carbon cloth

Adsorption on activated carbon cloth is an efficient procedure for removing pollutants from wastewaters, because this material possesses large specific area and high adsorption capacity. In\ud this study the activated carbon cloth was modified by mechanical milling in order to improve its sorption properties. The microstructure and morphology of the sample was investigated by XRD,\ud PSD and SEM and surface chemistry was characterized by potentiometric titrations. The result showed that microstructure and morphology was drastically changed with milling: particle sizes\ud reduction, agglomeration and the loss of fibrous structure occurred. These changes resulted in increase of the acidic and the base groups: the number of basic groups was increased by the factor of 11 while the number of acidic groups by the factor of 1.5

Synthesis and characterization of new Ti–Bi2O3 anode and its use for reactive dye degradation

This paper reports the synthesis, characterization and application of a Ti–Bi2O3 anode for the electrochemical decolorization of the textile dye Reactive Red 2. The anode was synthesized by electrodeposition on a Ti substrate immersed in an acidic bismuth (III) solution at constant potential, followed by calcination in air at 600 °C. Thermogravimetric Analysis (TGA), Energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis revealed that the electrodeposited material was predominantly metallic bismuth, which was oxidized to pure α-Bi2O3 during the calcination in air. SEM micrographs revealed that the Bi2O3 coat at the anode surface was inhomogeneous and porous. Reactive Red 2 was completely electrochemically decolorized at the synthesized anode in the presence of H2O2. The applied current density, H2O2 and Na2SO4 concentration, medium pH and initial dye concentration affected the dye decolorization rate. The optimal process parameters were found to be as follows: an applied current density of 40 mA cm−2 using a mixture of 10 mmol dm−3 H2O2 and 10 mmol dm−3 Na2SO4 at pH 7. The dye decolorization rate was shown to decrease as its initial concentration increased. The decolorization reactions were found to follow pseudo-first order kinetics

Influence of diatomite microstructure on its adsorption capacity for Pb(II)

The effect of microstructural changes caused by mechanical modification on adsorption properties of diatomite samples were investigated. The microstructure has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) while the degree of metal adsorption was evaluated by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP AES). The results show that metal sorption capacity of diatomite is considerably improved after mechanical modification and it can be attributed to amorphysation of the material. Immobilization efficiency increased from 22% for untreated to 81% for the treated sample after 5h at BPR 4.This qualifies natural diatomite as a material for wastewater remediation

Rietveld refinement of crystal phases (Ca1-xLax)MnO3 with perovskite-type structure

Two nanopowders with nominal compositions (Ca0.7La0.3)MnO3 (CLM) and (Ca0.7La0.3)(Mn0.8Ce0.2)O-3 (CLMC) were synthesized by a modified glycine/nitrate procedure. XRD analysis revealed binary phase mixture in both samples. The influence of La and Ce on unit cell parameters, atom positions, and average bond distances were analyzed. According to these results and refined occupation factors of La and Ca, as well as quantitative phase analysis it was found that the CLM sample consists of 85 mass.% of Ca0.62La0.38MnO3 and 15 mass.% of Ca0.99La0.01MnO3, while the CLMC sample consists of 70 mass.% of Ca0.58La0.42MnO3 and 30 mass.% of CeO2. Microstructure size-strain analysis was performed and the Rietveld refinement gave crystallites of about 100 angstrom. TEM images showed particle sizes of about 100-500 angstrom.Research Trends in Contemporary Materials Science, 8th Conference of the Yugoslav-Materials-Research-Society (Yu-MRS), Sep 04-08, 2006, Herceg Novi, Montenegr

Synthesis and dielectric behavior of lead-free (Na0.5Bi0.5)(1-x)BaxTi1-yTayO3 piezoelectric ceramics

Solid solution of (Na0.5Bi0.5)(1-x)BaxTi1-yTayO3 in the composition range x = 0.06 and 0.0 LT = y LT = 0.05 were prepared by conventional ceramics sintering technique. These new group of lead-free piezoelectric ceramic were studied for their crystal structure, dielectric and piezoelectric properties. It is shown that the system possess pure perovskite phase in its as calcined state. A morphotropic phase boundary (MPB) between tetragonal and rhombohedral phases appears at x = 0.06 and y = 0.05. The room temperature measurements of dielectric and piezoelectric properties reveal that the obtained ceramics with MPB composition has potential for use as piezoelectric material

Correlation between fracture toughness and microstructure of seeded silicon nitride ceramics

Microstructure development and fracture toughness of Si3N4 composites were studied in the presence of seeds and Al2O3 + Y2O3 as sintering aids. The elongated beta-Si3N4 seeds were introduced into two different alpha-Si3N4 matrix powders; one was the ultra fine powder matrix and the other was the coarse powder matrix. The amount of seeds varied from 0 to 6 wt%. The grain growth inhibition and the mechanism of toughening were discussed and correlated with microstructure. The maximum fracture toughness of 9.0 MPa m(1/2) was obtained for ultra fine powder with 5 wt% seeds hot pressed at 1,700 degrees C for 6 h

Nanopowders properties and sintering of CaMnO3 solid solutions

Pure and doped CaMnO3 were synthesized by applying modified glycine/nitrate procedure. The detailed structural characterization of prepared nanometric size powders, their properties, as well as the results on studying sintering and microstructure of the sintered bodies are given. Since the data on additive influence on densification of CaMnO3 during sintering are difficult to find in the literature, their role in densification is discussed. It was found that increasing Y concentration enhanced densification during sintering, and in addition, suppressed grain growth process. The results of the electrical conductivity measurements as a function of dopant concentration are also discussed. (C) 2007 Elsevier B.V. All rights reserved