The Use of Natural Zeolites of Transcarpathia to Solve Environmental Problems

Abstract

Purification of aqueous solutions from radionuclide contamination is an extremely problematic topic, which is the subject of many scientific papers. This scientific topic is very relevant to Ukraine. In particular, the synthetic adsorbents � activated carbon, zeolites, metal oxide-adsorbents TiO2, titanium or zirconium phosphates, ion exchange resins, etc., are often used for the removal of heavy metal cations Pb (II), Cd (II), Ba (II), Hg (II), Sr (II) as well as some anions Cl-, F- from the aquatic environment. A special place among adsorbents is occupied by ion exchange resins, which, as a rule, have an organic matrix, for example, styrene-vinylbenzene with functional groups fixed on it. Ion-exchange resins, along with titanium dioxide and activated carbon, are most widely used in industry to purify aqueous solutions from heavy metal cation and radionuclides. These numbered adsorbents are synthetic materials. However, some adsorbents were created by nature. Natural zeolite, deposits of which are in the Zakarpattya region of Ukraine, are among them. The use of natural zeolites of Transcarpathia can solve some environmental problems caused by 90Sr pollution in the aquatic environment. All chemical processes including adsorption occur in complicated mechanisms and are reversible. After some time, equilibrium has been introduced. These complex mechanisms can be divided into several simple stages, which can be described by a relatively simple mathematical equation. In this study, the adsorption of Sr2+ ions from aqueous solutions by natural zeolite was investigated. And four most common kinetic models were applied for analysis of the experimental adsorption data.