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Environmental Chemistry

Research topics

  • the influence of anthropogenic activities on the quality of groundwater, surface water and soil, mainly related to the heavy metal contamination and eutrophication
  • the speciation analysis of selected metals (e.g. As, Cr)
  • the sorption properties and kinetic of heavy metals adsorption on natural bentonites
  • the use of spacers in capillary isotachophoresis
  • the analysis of environmental samples using ITP, CZE and AAS methods
  • management of hazardous chemical substances

Available apparatus

  • Atomic Absorption Spectrometer with electrothermal and flame atomization and hydride technique, GBC, Australia
  • Capillary Electrophoretic analyzer with modules ITP and CZE, Villa Labeco, Spišská Nová Ves, Slovak Republic and with programmable UV-VIS detector, ECOM, Czech Republic and DAD detector Smartline 2850, KNAUER, Germany
  • HPLC with DAD detector and fluorescent detector, Agilent, USA
  • GC-MS, Agilent, USA
  • IR Spectrometer with Raman modul, Thermo Fisher Scientific, USA
  • Polarograph Metrohm 797 Computrace, Metrohm, Switzerland
  • Measuring equipment WTW Multi 340i, Germany

We examine the risks in the environment

In our laboratory we deal with the analysis of surface and ground water, analysis of sludge, soil, plant material and clay minerals. We provide speciation analysis of ionic forms of the metals due to their different toxicological properties. Based on the results of performed analyses we assess the risks, and propose appropriate solutions for metal elimination using natural sorbents based on bentonite. We also study sorption properties of natural bentonites in detail.

Analysis of water, soil, sludge, plant material and clay minerals

At sampling in the field we determine the basic physical-chemical parameters such as temperature, pH, conductivity, content of dissolved oxygen. The method of capillary zone electrophoresis (CZE) is used for the analysis of anions (Cl-, SO42-, NO3-, NO2-, F-, PO43 -, AsO43-). Atomic absorption spectrometry (AAS) and the method of capillary isotachophoresis (CITP) are used for the analysis of metals (Cu, Pb, Zn, Cd, Fe, Co, Ni, Mn, K, Na, Mg, Ca). Due to different toxicological properties of ionic forms of metals we deal with their speciation analysis.

Analysis of metal ions - CITP method

Analysis of metal ions - CITP method

Electrophoretic analyser EA 100 with modules for capillary isotachophoresis (CITP) and capillary zone electrophoresis (CZE) with conductivity and UV-VIS photometric detector (Villa Labeco, Spišská Nová Ves)

Electrophoretic analyser EA 100 with modules for capillary isotachophoresis (CITP) and capillary zone electrophoresis (CZE) with conductivity and UV-VIS photometric detector (Villa Labeco, Spišská Nová Ves)

Analysis of anions - CZE method

Analysis of anions - CZE method

Microwave decomposition system Speedwave MWS-2 (Berghof, Germany)

Microwave decomposition system Speedwave MWS-2 (Berghof, Germany)

Atomic absorption spectrometer AVANTA Σ with flame atomization (GBC, Australia)

Atomic absorption spectrometer AVANTA Σ with flame atomization (GBC, Australia)

Atomic absorption spectrometer AVANTA Σ with flame atomization (GBC, Australia)

Atomic absorption spectrometer AVANTA Σ with flame atomization (GBC, Australia)

 


Study of sorption properties of bentonites

Heavy metal pollution is a serious problem for the environment. Heavy metals such as Pb, Cr, Cu, Zn, Sb, Hg, As and Cd, etc. are toxic inorganic pollutants in surface and ground water and, by their properties, threaten all living organisms and humans.

Traditional technologies for the removal of heavy metals from water and wastewater include precipitation, ion exchange, adsorption, coagulation, electrolysis, extraction membrane separation and reverse osmosis. However, most of these methods may be extremely expensive or ineffective when the metals are dissolved in large volumes of a solution at a relatively low concentration. Adsorption is very often used for wastewater treatment, because it is financially less costly. Various substances, such as activated carbon, ion exchange resins, zeolites and bentonites have been used as adsorbents for removal of heavy metals from wastewater.

Clays have typical properties (large surface area, high cation exchange capacity, chemical and mechanical stability and a layered structure) that predispose them to be good adsorbents. Bentonite belongs to the group of clay minerals. The main constituent of bentonite is montmorillonite, composed of units made up of two silica tetrahedral sheets with a central alumina octahedral sheet.

 The structure of montmorillonite

The structure of montmorillonite

The isomorphous substitution in tetrahedral and octahedral sheets results in a net negative surface charge on the clay. The resulting negative charge is balanced by hydrated exchangeable cations (e.g. H+, Na+ and Ca2+) adsorbed between the layers and around their edges. A number of studies have been reported using clays, mainly montmorillonite, and have shown their effectiveness for the removal of metal ions such as Pb2+ and Cu2+ ions from aqueous solution.

In our laboratory, we study metal sorption and observe the influence of various factors (such as effects of pH, metal concentration, amount of adsorbent, etc.) on the sorption properties of Slovak bentonites. We also evaluate their sorption properties with the aim of using them in the removal of toxic metals from mining and waste water.

X - ray diffraction patterns of bentonite from deposits in Lieskovec (L) and in Jelšový potok (JP)

X - ray diffraction patterns of bentonite from deposits in Lieskovec (L) and in Jelšový potok (JP)


 Selected publications

  1. ANDRÁŠ, P., NAGYOVÁ, I., SAMEŠOVÁ, D., MELICHOVÁ, Z.: Study of the Environmental Risks at the Old Spoil Dump Field Lubietova – Slovakia. Pol. J. Environ. Stud. 2012, 21 (6), 1529-1538.
  2. BRTÁŇOVÁ, A., MELICHOVÁ, Z., KOMADEL, P.: Removal of Cu2+ from aqueous solution by Slovak bentonites. Ceramics - Silikáty. 2012, 56, 55-60.
  3. ANDRÁŠ, P., MELICHOVÁ, Z., NAGYOVÁ, I., SAMEŠOVÁ, D.: Distribution of selected heavy metals at the Ľubietová deposit (central Slovakia). In: 13. Ősterreichische Chemietage, Book of Abstracts, Vienna, 2009, 122.
  4. MELICHOVÁ, Z., SCHABJUK, M., KOPÁČEK, J.: Seasonal dynamics of nitrogen forms in an alpine stream in the Tatra Mountains. In: Acid Rain 2005. 7th International Conference on Acid Deposition. Prague, 2005, 667.
  5. MARÁK, J., NAGYOVÁ, I., KANIANSKY, D.: Computer –assisted choice of discrete spacers for anionic isotachophoresis separations. J. Chromatogr. A, 1018 2003 s. 233-249.
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