Elektrokinetinio valymo metodo taikymo sunkiaisiais metalais užterštiems dirvožemiams valyti tyrimas ir vertinimas

Abstract

For investigation of electrokinetic remediation an apparatus was created. An apparatus was designed from a Plexiglas panel, which is divided by permeable membranes into 3 sections (in one of them polluted soil is placed). Permeable membranes are made of filer paper covered perforated Plexiglas walls. In other two sections an anode (graphite stick) and a cathode (perforated stainless steel plate) are placed, and they are connected with power supply. Both electrode sections are 1/3 of panel height filled with natural sorbent (zeolite), which is used for heavy metals ions sorption. Also, there is an electrolyte solution supply and drainage systems installed. When power supply is turned on, and the electric current is induced, in the middle section of an apparatus and in the sections with zeolite an electric field is created. The movement of pollutants is induced because of electro osmosis and ion migration. Electro osmosis mobilizes pore water in soil medium, and ion migration dissociates anions and cations, which then migrates towards the anode and cathode. Such transportation together with geochemical reactions (desorption, solution and conjungation) are the fundamental basis of electrokinetic process. Zeolite is capable to bind metal cations, and because of that pollutants, which were removed from soil, are then collected in zeolite layer. The investigation was performed with Cu, Ni and Mn pollutedsoils (loam, sandy loam, and sand), using 29V and 24V voltage.