Manilo M.V.,Ferenc Rakoczi II Transcarpathian Hungarian Institute |
Manilo M.V.,NASU F. D. Ovcharenko Institute of Biocolloidal Chemistry |
Choma Z.Z.,Ferenc Rakoczi II Transcarpathian Hungarian Institute |
Barany S.,Ferenc Rakoczi II Transcarpathian Hungarian Institute |
Barany S.,University of Miskolc
Colloid Journal | Year: 2017
The adsorption of trivalent chromium ions from aqueous solutions on the surface of carbon materials, namely, multiwall carbon nanotubes (NTs) and two samples of active carbon, is studied depending on pH and adsorbate concentration in the system. Isotherms of Cr(III) adsorption by the aforementioned materials are obtained. It is shown that chromium ions are predominantly bound by surface carboxyl groups. The adsorption of chromium ions reduces the electrokinetic potential of NTs and, at chromium concentrations CCr(III) > 10–5 M, leads to the reversal of the surface charge. The adsorption value decreases in the series NT > Merck carbon > Norit carbon, in contrast to an increase in the adsorbate affinity to the adsorbent in this series, as determined from the slope of the initial section of the Langmuir isotherms. Small amounts of chromium ions sorbed at low concentrations in solution (CCr(III) ≤ 10–5 M) are comparable with the concentration of hydrogen ions displaced from the surface, thus making it possible to suppose the existence of an ionexchange adsorption mechanism. As the concentration of Cr(III) increases, the equivalent displacement of H+ is violated, thereby indicating the development of other adsorption mechanisms (complexation). © 2017, Pleiades Publishing, Ltd.
Szanyi S.,Debrecen University |
Nagy A.,Institute of Management Sciences |
Molnar A.,Ferenc Rakoczi Ii Transcarpathian Hungarian Institute |
Katona K.,Debrecen University |
And 2 more authors.
Acta Zoologica Academiae Scientiarum Hungaricae | Year: 2017
We allocated some new types of bait traps using different volatile aromatic compounds in the Velyka Dobron' Game Reserve (Ukraine, Transcarpathian region) where light trap surveys on Macroheterocera were already carried out since 2009. The phenylacetaldehydebased traps were especially effective for the species of subfamilies Plusiinae and Heliothinae, while the members of some other subfamilies (Hadeninae, Noctuinae) were more attracted by the isoamyl-alcohol-based traps. The highest attractivity was observed in case of the mixture containing isoamyl-alcohol, acetic acid and red wine. The highest number of species was observed in mid-July, but the peak of individual numbers appeared in early August. Majority of species of this assemblage was formed by bivoltine species connected to herbaceous food plants. The dominant species of this late summer period was Trachea atriplicis (second brood). It was sharply replaced by the monovoltine Allophyes oxyacanthae in September. The bulk of species of this early autumnal period was formed by monovoltine species with woody-shrubby larval food plants. Biogeographical spectrum of the assemblage was dominated by widely distributed Euro-Siberian species combined with significant presence of Mediterranean and Boreo-continental faunal elements. in the ecological spectrum of the assemblage the species connected to forested habitats are well represented but together with the presence of numerous generalist species.
Szabo S.,Debrecen University |
Gosztonyi G.,Debrecen University |
Babka B.,Debrecen University |
Docs N.,Debrecen University |
And 11 more authors.
Studia Universitatis Vasile Goldis Arad, Seria Stiintele Vietii | Year: 2010
Since it is Hungary's second largest river, the River Tisza is important both as a river and because of its active floodplain. The contaminations endanger the aquatic and the related living nature as well as the farming in the active floodplain. The water quality of the river is examined regularly by the competent authority but far less information is available about the active floodplain. More data is necessary in order to estimate the potential danger. In this paper the River Tisza and its tributaries were examined, especially considering the metal accumulation and its relation to the soil characteristics. We started to create the database in 2004 and several tasks were achieved: the metal content of the root zone in the active floodplain (horizontal distribution); the metal content of the upper 1 m zone in the active floodplain (vertical distribution); the general water chemical and isotope analyses and the metal content of the oxbow lakes near the River Tisza; the metal content of the sediments of the oxbow lakes. More than 300 surface soil samples, 18 soil profiles (18 × 50 samples) and 45 oxbow lakes were examined up to now. Cu, Co, Fe, Ni, Mn, Zn contents were determined in every case and As, Cd, Pb determinations were also carried out in reasonable cases. ArcGIS 9.0 was applied in order to create the spatial database and the statistical analyses of the data were carried out with SPSS. In this paper some case studies will be presented. © 2010 Vasile Goldis University Press.
Barany S.,University of Miskolc |
Barany S.,Ferenc Rakoczi II Transcarpathian Hungarian Institute |
Meszaros R.,University of Miskolc |
Taubaeva R.,Taraz State Pedagogical Institute |
Musabekov K.,Al-Farabi Kazakh National University
Colloid Journal | Year: 2015
The influence of pH and KCl, CaCl2, AlCl3, sodium dodecyl sulfate, and cetyltrimethylammonium bromide (CTAB) concentrations on electrokinetic potential ζ of particles and the electrical conductivity of aqueous kaolin and bentonite suspensions has been studied. At “natural” pH values of the suspensions (7.2–7.4), the ζ potential of bentonite is much higher (–45 mV) than that of kaolin (–20 mV), and this difference takes place in a wide pH range (2–11). In both cases, a rise in pH leads to an increase in the absolute values of ζ due to the enhanced dissociation of surface OH groups. Charge reversal is observed at pH of approximately 2 and pH 2.5 for kaolin and bentonite, respectively. The dependence of the ζ potential of the particles on KCl concentration passes through a maximum, while the addition of CaCl2 and AlCl3 causes a substantial reduction in ζ and particle charge reversal, respectively. An increase in CTAB concentration C in a suspension leads to a decrease in the negative ζ values followed by particle charge reversal, with the ζ(C) curve tending to reach a plateau. It has been shown that the initial regions of the dependences of the relative electrical conductivities of the suspensions on the volume fraction of the solid phase are almost linear, with their slopes decreasing with a rise in electrolyte concentration. Hence, the contribution of the surface conductivity to the total suspension conductivity decreases with a rise in the ionic strength of a solution. The values of the electrokinetic charge calculated from the data on the ζ potential, i.e., the charge of the slipping plane, have appeared to be one to two orders of magnitude lower than the surface charges of the minerals. This finding suggests that counterions are predominantly located in the hydrodynamically motionless part of the electrical double layer. © 2015, Pleiades Publishing, Ltd.
PubMed | Ferenc Rakoczi Ii Transcarpathian Hungarian Institute, BioAqua Pro LTD, Kossuth Lajos Secondary Grammar School, Mta Of Biodiversity And Ecosystem Services Research Group and Debrecen University
Type: | Journal: Ecotoxicology and environmental safety | Year: 2016
Odonata larvae are frequently used to assess the contamination of aquatic systems, because they tolerate a wide range of chemical and biological conditions in freshwater systems. In early 2000, the sediments of the Hungarian section of the River Tisza and the River Szamos were strongly enriched with heavy metals by an accidental mining spill. Earlier studies demonstrated higher contamination levels in the Szamos than in the Tisza, based on sediment analysis. The aim of our study was to assess the contamination in the Upper Tisza Region, along the upper reach of the Tisza, and the lower reach of the Szamos, based on the trace element concentrations of the Gomphus flavipes larvae. We collected 269 dragonfly specimens for the analyses. The Al, Ba, Cr, Cu, Fe, Mn, Pb, Sr and Zn element contents were analysed in the dragonfly larvae by microwave plasma atomic emission spectrometry (MP-AES). Significantly higher Ba and Cu concentrations were found in the dragonfly larvae of the Tisza than the Szamos. In spite of this, the Cr, Mn, Pb, Sr and Zn concentration was significantly lower in the dragonfly larvae of the Tisza than the Szamos. For all trace elements significant differences were found along the Tisza. Significant differences were also found in all trace element concentrations of dragonfly larvae among studied localities in the Szamos, except in the cases of Al and Ba. Our results demonstrated that the Szamos was more contaminated with Cr, Mn, Pb, Sr and Zn than the Tisza, but that the Tisza was more contaminated with Ba and Cu than the Szamos, based on the trace element concentrations in Gomphus flavipes larvae, which was likely to have been caused by the tributaries of the Tisza. In summary, our results indicated a continuous pollution of the Tisza and the Szamos and their tributaries.
Karacsonyi D.,Hungarian Academy of Sciences |
Kocsis K.,Hungarian Academy of Sciences |
Kovaly K.,Eötvös Loránd University |
Molnar J.,Ferenc Rakoczi Ii Transcarpathian Hungarian Institute |
Poti L.,Hungarian Institute of International Affairs
Hungarian Geographical Bulletin | Year: 2014
In his work the Clash of Civilizations S.P. Huntington classified Ukraine as a "cleft country." In our view, the current discord in Ukraine is rooted in the political divisions that have frequently characterised the post-communist countries. In Ukraine, owing to a history of divergent socio-economic development in the various regions, these divisions are strongly regional. The dichotomic socio-economic framework reflects not only ethnic and religious differences but also such factors as urbanisation, economic development, and even natural elements. The resulting political divide in Ukraine may be traced to the dichotomy of its national identity. The dividing line is between east and west, urban and rural, and Russian-speaking and Ukrainian-speaking Ukraine. Politically, it is between "Maidan-Ukraine" and "Anti-Maidan-Ukraine". The divide runs along the Uman'-Kharkiv line between the forest zone and the steppe. In the 18th century the steppe - which had once been a corridor for the nomadic peoples - became a frontier territory for the Ukrainians and then for Tsarist Russia. The Russian ties of cities in the region were further strengthened by industrialisation in the 19th and 20th centuries and by Russification in the Soviet era. The Soviet-made famine (Holodomor) and the events of World War II (the actions of the UPA) heightened Ukraine's political dichotomy. Since independence Ukraine's political elite has failed to address the problem in an adequate manner. The recent escalation of the conflict is due to a lack of political cohesion in the young state and the gravitational effect of the major powers rather than primarily to some kind of civilizational difference. By accentuating Ukraine's economic and financial difficulties, the global crisis has made the country even more vulnerable.