Wyniki wyszukiwania - Biblioteka Nauki

1

Na-P1 zeolite synthesis and its crystalline structure ripening through hydrothermal process using coal combustion by-products as substrates

100%

Kunecki P. , Panek R. , Wdowin M.

Geology, Geophysics and Environment

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2016

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tom Vol. 42, no. 1

90--91

EN

Energy industry sector is one of the major environment pollutants. This branch also generates significant amounts of by-products such as slugs, slug-ash mixtures, ashes and microspheres, which can be very harmful for the earth ecosystems. Statistically the microspheres (MIC) constitute from 0.6% to 2.5% of the total amount of post combustion wastes. MIC occurs mainly in fly ashes (less often in slugs) as the smallest, hollow, spherical particles. MIC is composed mainly of crystalline and amorphous aluminosilicate phases. The combustion conditions have strong influence on MIC composition. Mineral and chemical composition of MIC is very similar to F type of fly ashes; consequently there is a possibility to use them as substrates for zeolite synthesis. Zeolites are minerals from microporous, aluminosilicate group (Szala et al. 2015). Among others, they are characterized by specific channels and chambers occurrence in their structure, which results in a number of important features like: ion exchange, sorption, molecular sieve or catalytic properties. This is the reason for wide use of zeolites in numerous industrial sectors (Ahmaruzzaman 2010). The aim of this study is a synthesis of Na-P1 zeolite at semi-technical scale by conversion of microspheres under hydrothermal conditions in an alkaline medium. This study involves also research of Na-P1 zeolite structure ripening in order to optimize the synthesis conditions. Microspheres from Stalowa Wola Power Plant (Poland) were used as a substrate. For the synthesis of Na-P1 phase the following conditions were applied: 90 dm 3 of water, 15 kg of microsphere, 11 kg of sodium hydroxide (3 mol/dm 3 ), temperature: 80°C, and reaction time up to 26 h (Franus et al. 2014). The zeolite conversion was performed on semi-technical scale installation (Wdowin et al. 2014). During the conversion, samples were collected from the reactor after 2, 4, 6, 10, 14, 26 hours. To investigate the influence of time for zeolitization process efficiency these samples were analyzed in terms of chemical and mineral composition, structural and textural properties. The main attention was paid to the evolution of the Na-P1 unit cell parameters observed as a function of time (calculations and models were performed for every sample). The phase’s composition was determined with powder X-ray diffraction (XRD) method using a PANalytical X’pert MPD diffractometer (with a PW 3050/60 goniometer), Cu lamp, and a graphite monochromator. The analysis was performed within the angle range of 5–65 2θ. PANalytical X’Pert Highscore software was used to process the diffraction data. The identification of mineral phases was based on the PDF-2 release 2010 database formalized by the ICD and IZA-SC Database of Zeolite Structures. The experimental calculations of the unit cell parameters were performed using UnitCell software. The spatial model of Na-P1 zeolite cell was prepared using Mercury 3.7 Windows software. The morphological forms and the chemical composition of the main mineral components were determined with scanning electron microscope (SEM) FEI Quanta 250 FEG equipped with the SE detector and a system of chemical composition analysis based on energy dispersive X-ray-EDS of EDAX company. N 2 adsorption-desorption measurements were carried out at 77 K using ASAP 2020 volumetric adsorption analyzer (Micromeritics). The specific surface areas (S BET ) of the samples were evaluated using the standard Brunauer–Emmett–Teller (BET) method for nitrogen adsorption data in the range of relative pressure p / p 0 from 0.06 to 0.3. The total pore volumes were estimated from single-point adsorption at a relative pressure of 0.98. XRD data indicates that main phases in microsphere are amorphous aluminosilicate glass, mullite and quartz. The obtained product is dominated by Na-P1 phase. Experimental calculations of cell parameters and fabricated models confirm crystallographic similarity to Na-P1 pattern. Noteworthy is the fact that the unit cell parameters depend on reaction time. Calculations indicate that the cell parameters (walls length: a , b , c and cell volume) increase with time towards to pattern values. This phenomenon may be interpreted as a ripening of crystalline structure. An in-depth look at this matter can lead to better estimation of synthesis conditions, which have a significant impact to the total cost of zeolites production – especially at a larger scale. SEM shows progressive dissolution (also as a function of time) of aluminosilicate glass in favor of crystallization of zeolite phase. EDS analysis confirms similarity of chemical composition of the obtained samples to a standard Na-P1 zeolite. Calculated textural properties indicate increase of S BET with the reaction time. Simultaneously, the average pore diameters decrease. The S BET of synthetized Na-P1 was 4.62 m 2 /g after 2 h but it increased to 47.92 m 2 /g after 26 h. This is an effect of growing contribution of zeolite phase in relation to the initial substrates in the sample during the reaction time. The experimental conditions allowed synthesizing Na-P1 zeolite from microsphere particles in the prototype installation. Zeolitization process strongly influences the textural properties by increasing S BET and improving pore structure. The microsphere from Stalowa Wola Power Plant is a promising material for the synthesis of Na-P1 zeolite in the prototype installation. Still, the reaction parameters should be reconsidered, basing on the obtained results, in order to reduce the cost of the zeolite production as much as possible. This is required before proceeding to the full technical production scale. To observe increase of zeolite amount in entirety synthesis batch (and to link it with cell behavior) the Rietveld analysis will be provided.

2

Dichlorvos toxicity on fish - a review

88%

Deka S. , Mahanta R.

European Journal of Biological Research

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2015

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tom 05

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nr 3

3

Interactions of mercury in the environment

88%

Maluszynska I. , Popenda A. , Maluszynski M. J.

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tom 45

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nr 2

EN

Mercury is a pollutant of global concern largely due to its potential for biological transformation into harmful forms and bioaccumulation through the food chains. Mercury is not able to biodegrade in the environment and it forms many toxic inorganic and organic complexes. The strongest harmful effects of mercury concerns the central nervous system. The harmful effects of mercury is very stable, because the mercury compounds bind to enzymes. Getting into the brain, mercury displace zinc from brain tissue, and thus reduces the effi ciency of the brain. Then excreted in the cell nuclei and destroys the genetic material. The antagonism between zinc and mercury partially modifies its toxic effects. Mercury is combined with active groups of proteins and amino acids, accumulating in the body. Selenium has similar affinity, limiting connects these groups with mercury, reducing its toxicity. Antagonists are also cadmium, mercury and zinc, but their effects are most likely related with the action of selenium. Antagonist for mercury is also iodine content in the thyroid gland which is lowered, the excessive concentration of mercury in the body. It is known that taking selenium, zinc and thiols, e.g. GSH and NAC, are of prime importance in considering effects on human organisms as well as the level of its excretion. Due to the fact that interactions are dynamic and poorly understood at present the better understanding of their role requires the further studies. Despite that have been identifi ed interactions between elements and mercury, limiting its toxic effects, we still do not have sufficient knowledge about how to reduce the negative effects of this element on the human body. The definition of what is an acceptable daily dose of mercury for humans also does not quarantee protection of the health, because we do not know the exact limits of tolerance for different follow-up effects of prolonged exposure to low concentrations. It should also be pointed out that the interactions are dynamic and weakly understood at present. The better understanding of the role the afore-mentioned particles may be crucial in the to study the interaction between mercury and various environmental components and to find a substance that interacts with mercury to reduce its toxicity to living organisms.

PL

Rtęć jest zanieczyszczeniem stanowiącym ogólnoświatowy problem w dużej mierze ze względu na możliwości przekształcenia w szkodliwe formy, a także bioakumulację w łańcuchu pokarmowym. Rtęć w środowisku nie ulega biodegradacji i tworzy wiele toksycznych nieorganicznych i organicznych kompleksów. Najsilniejszy szkodliwy wpływ rtęci dotyczy ośrodkowego układu nerwowego. Szkodliwe działanie rtęci jest bardzo trwałe, ponieważ związki rtęci łączą się z enzymami.Dostając się do mózgu, rtęć wypiera z tkanki mózgowej cynk, osłabiając sprawność mózgu, a następnie przenika do jąder komórkowych i niszczy materiał genetyczny. Antagonizm pomiędzy cynkiem i rtęcią częściowo modyfi kuje jej toksyczne działanie. Rtęć łączy się z aktywnymi grupami białek i aminokwasów, kumulując się w organizmie. Podobne powinowactwo wykazuje selen, ograniczając łączenie się tych grup z rtęcią, zmniejszając jej toksyczność. Antagonistami rtęci są również kadm i cynk, ale ich działanie jest najprawdopodobniej powiązane z działaniem selenu.Antagonistą dla rtęci jest również jod, którego zawartość w tarczycy ulega obniżeniu przy nadmiernym stężeniu rtęci w organizmie. Wiadomym jest, iż pobór selenu, cynku oraz niektórych tioli, np. GSH i NAC, również poziom ich wydalania są kluczowe w rozważaniu ich wpływu na organizmy żywe. Biorąc pod uwagę fakt, że reakcje zachodzące pomiędzy nimi są dynamiczne i słabo poznane, lepsze zrozumienie ich roli wymaga dalszych badań. Pomimo stwierdzenia występowania interakcji z pierwiastkami ograniczającymi toksyczne działanie rtęci, nadal nie mamy wystarczającej wiedzy na temat możliwości zmniejszenia negatywnych skutków działania tego pierwiastka na organizm człowieka. Określenie dopuszczalnych dziennych dawek rtęci dla człowieka, również nie gwarantuje zabezpieczenia stanu jego zdrowia, gdyż nie są znane dokładne granice tolerancji na różne następcze skutki długiego działania niskich stężeń tego pierwiastka. Należy również podkreślić, że zjawisko interakcji jest nadal słabo rozpoznane i podlega ciągłym zmianom. Lepsze zrozumienie roli wcześniej wymienionych składników może być konieczne w celu określenia oddziaływania pomiędzy rtęcią i różnymi składnikami środowiska oraz znalezienia substancji, które wchodzą w interakcje z rtęcią, zmniejszając jej toksyczność dla organizmów żywych.

4

Effect of cadmium speciation on 109Cd uptake and toxicity to Staphylococcus aureus

88%

Malm A. , Tynecka Z. , Zajac J.

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tom 07

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nr 3

EN

Cadmium is an environmental pollulant highly toxic to all forms of life. In this paper we studied by polarography the effect of the environment on cadmium speciation and also the effect of this speciation on 109Cd uptake and toxicity to living cells of cadmium-sensitive Staphylococcus aureus 17810S in different media. It was found that the magnitude of passive ,09Cd adsorption was proportional to the content of free Cd2+ in the medium (cadmium speciation). In contrast, the magnitude of energy-requiring l09Cd accumulation did not depend on cadmium speciation and was similar in all media. This could be due to the higher affinity of Cd2+ to the Mn2+ transport system than to the complexing ligands in the medium. Thus, cadmium uptake by S. aureus 17810S depends both on environmental and cellular factors and under all circumstances results in strong toxicity to living cells.

5

Binding of cadmium in the renal medulla of humans not exposed occupationally to cadmium

88%

Orlowski C. , Piotrowski J. K. , Swiercz R.

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nr 2

6

Migracija i transformacija FPGS v okruzhajushhejj srede pri popadanii ikh v pochvu s osadkami stochnykh bod

75%

Valkina E. , Vernezi S. , Nikolenko I.

Motrol. Motoryzacja i Energetyka Rolnictwa

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2014

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tom 16

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nr 5

7

Zastosowanie czysciejszych technologii w polskim przemysle spozywczym

75%

Gornowicz E.

Biuletyn Informacyjny Drobiarstwa

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1992

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tom 30

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nr 5

29-32

8

Effects of cadmium on growth, ultrastructure and content of chemical elements in Tetrahymena pyriformis and Acanthamoeba castellanii

75%

Krawczynska W. , Pivovarova N. N. , Sobota A.

Acta Protozoologica

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1989

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tom 28

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nr 3-4

9

A study of the complexation reaction of mercury (II) with rhodarnine B from the point of view of its utilization in assaying mercury by the luminescence method

75%

Trojanowski J. , Ston M. , Szmacinski H.

Oceanologia

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1981

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tom 13

10

Potentiometric lead [II] ions recognition by liquid membrane electrodes incorporating methoxy substituted arylenevinylene derivatives

75%

Zimkus A. , Crestscu I. , Grzybowska I. , Radecka H. , Geise H. J. , Dieltiens P. , Aleksandrzak K.

Polish Journal of Environmental Studies

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2003

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tom 12

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nr 6

EN

The potentiometric responses towards lead ions of liquid membrane electrodes containing arylenevinylene derivatives are reported. The membranes respond to lead ions in the activity range 10-6 - 10-3 M and show good selectivity against common interfering mono- and doubly-charged cations. The new ligands demonstrate low affinity for protonation. 1 mol % (vs the ionphore) of potassium tetrakis(p- chlorophenyl)borate was used as a lipophilic anionic salt to improve the selectivity. The ligands selected for the present study allow estimating the influence of olefinic double bounds, the number of aromatic rings and the number and position of methoxy groups on recognition process of the lead ions.

11

Synthetic measures of health effects related to environmental hazards

75%

Konczalik J. , Dutkiewicz T.

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nr 3

12

Alternative pathways of polycyclic aromatic hydrocarbons activation: the formation of polar DNA adducts

75%

Baer-Dubowska W.

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1999

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tom 46

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nr 2

EN

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, and some are potent carcinogens in rodents. Carcinogenic PAHs are activated in the cells to metabolites that react with DNA to form covalent adducts. For most PAHs the reactive, electrophilic species which bind to DNA, are bay-region diol-epoxides. Application of 32-postlabeling to PAH-DNA adducts analysis revealed that for some PAHs the adduct profiles generated in model systems are more complex and include adducts which are more polar than those formed by classic bay-region diol-epoxides. This minireview summaries the information gained on typical representatives of polar PAH-DNA adducts. Formation of triol-epoxide-DNA adducts was proposed for chrysene and a non-alterant PAH, benzo[b]fluoranthene (B[b]F). 5-OH-B[b]F, the precursor of B[b]F triol-epoxide, was found to be a potent tumor initiator in mouse skin. For planar PAHs such as dibenzanthracenes the possibility of bis-diol epoxide-DNA adducts formation was suggested. The most comprehensive data were obtained for dibenz[a,j]anthracene (DB[a,j]A). This hydrocarbon when applied to SENCAR mouse skin forms up to 23 species of adducts, most of which are polar. Among these polar adducts seven were identified as derived from DB[a,j]A-3,4-10,11-bis-diol. Analysis of tumor-initiating activity showed, however, that this proximate metabolite was inactive in this respect. In contrast, an excellent correlation was observed between levels of less polar DNA adducts (i.e. those derived from bay-region diol-epoxides) and skin tumor initiating activity of DB[a,j]A. Thus, while triol-epoxides seems to be involved in tumor initiating activity of the parent compound, non alterant B[b]F, the significance of bis-diol epoxide-DNA adducts, at least those derived from DB[a,j]A, is minor.

13

Modern trends in monitoring and analysis of environmental pollutants

75%

Namiesnik J.

Polish Journal of Environmental Studies

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2001

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tom 10

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nr 3

EN

Both activities on quality improvement of the environment and a willingness to understand these processes are conditional on possessing reliable information that can be obtained from analytics and environmental monitoring. At present, analytics and environmental monitoring are among the most dynamically developing branches of chemical analysis. The pursuit of getting the complex information on environmental quality leads to developing new methods and analytical techniques. Previous studies and own experience entitle to present the most important tendencies in the development of analytics and environmental monitoring. These trends can be classified into two basic groups: - development of new methodical procedures, - new achievements in construction of measuring instruments (instrumentation). This paper presents the most important developments in both trends observed in chemical analysis.

14

Effect of stationary phase structural properties on retention and selectivity of EPA-NIST-PAH in reversed phase liquid chromatography

75%

Buszewski B. , Gadzala R. M. , Lodkowski R. , Sander L. C. , Jaroniec M.

Polish Journal of Environmental Studies

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1994

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tom 03

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nr 3

EN

A new type of stationary phase with specific structural properties and different undersurface structure (monomeric and polymeric) for liquid chromatographic separation has been prepared. This phase was applied for the separation of polycyclic aromatic hydrocarbons (PAHs), particularly those, recommended by the U.S. National Institute of Standards and Technology (NIST) and the U.S. Environmental Protection Agency (EPA). For comparative studies the commonly-used C-18 phase, with monomeric and polymeric structure created on the same batch of silica gel support, was applied. Physico-chemical and chromatographic properties were determined using different instrumental methods (porosimetry, elemental analysis, CP/MAS NMR, liquid chromatography), particularly under hydro-organic conditions.

15

Badanie możliwości wiązania zanieczyszczeń z odpadków komunalnych przez popioły lotne

63%

Agopsowicz M.

|

tom 16

16

Evaluation of the combined effect of cadmium, benzo[a]pyrene and pyrene in general toxicity studies on Wistar rats

63%

Paltanaviciene A. , Zabulyte D. , Kalibatas J. , Uleckiene S.

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tom 63

|

nr 01

51-55

EN

Heavy metal cadmium (Cd) and polycyclic aromatic hydrocarbons benzo(a)pyrene (B(a)P) and pyrene (P) are ubiquitous and persistent environmental pollutants. Human beings are constantly exposed to mixtures of these substances. Exposure to Cd may cause changes in critical organs kidneys and liver. B(a)P has an adverse effect on haemopoesis, digestive systems and on the liver. According to some data Cd, B(a)P and P may interact in all the metabolism phases of xenobiotics. The objective of our study was to investigate the combined effect of Cd, B(a)P and P on general toxicity of the organism of Wistar rats. Tests were conducted on the basis of the methodical recommendations: 407 and 408 of the OECD Guidelines for the Testing of Chemicals. In the experiment, 176 male Wistar-line rats were employed. Four different dose levels were used: 0.1, 0.5, 1.92, 4.0 mg/kg for Cd; 0.00015, 0.0015, 33.3, 10.0 mg/kg for B(a)P and 0.00075, 0.0075, 90.0, 20.0 mg/kg for P and their 4 combinations. The complex of substances studied induced changes in the biochemical blood, urinalysis, hematological parameters which indicated renal and liver function damage and evoked leukopenia symptoms. Evaluating the complex of the substances by these parameters it was noted that the combined action of substances had three types: antagonistic - 56.9%, additive - 27.4% and unknown origin - 15.7%.

17

Ekologiczne, ekonomiczne i polityczne problemy transgranicznych zanieczyszczen srodowiska przyrodniczego

63%

Gora E. , Drozdz A.

|

tom 31

|

nr 1-2

59-78

18

Tris[chlorofenylo]metan i tris[4-chlorofenylo]metanol- zanieczyszczenia srodowiska i zywnosci

63%

Falandysz J.

|

1994

|

tom 27

|

nr 4

311-316

19

Problemy ochrony roslin w agrocenozach zanieczyszczonych przez emisje przemyslowe

63%

Przybylski Z.

Biuletyn Informacyjno-Handlowy. Ośrodek Doradztwa Rolniczego Boguchwała

|

1995

|

nr 01

3-4

20

Influence of polychlorinated biphenyls on the secretion of oxytocin from bovine luteal cells and from granulosa cells obtained from the follicles of different size

63%

Mlynarczuk J. , Kotwica J.

Polish Journal of Veterinary Sciences

|

2005

|

tom 08

|

nr 4