Abstract
Fenton reaction is often used for the treatment of industrial wastewaters polluted by a toxic and difficult to remove compounds where other methods as emulsion breaking chemical precipitation, or advanced chemical processes fail. To this category belong phenols, polychlorinated aromatic hydrocarbons, amines, mercaptans, and stable chemical complexes containing heavy metals at different concentrations and sometimes even radioactive isotopes. These wastewaters can cause severe damage to the environment, so their removal has a high priority. The principle of Fenton’s reaction is based on radical oxidation of the difficult to remove compounds realised by the application of oxidising reagent catalysed by the addition of metallic cations as an oxidant is frequently used hydrogen peroxide, ozone, or chloride lime which allows production of the hydroxyl radicals. As a catalyst, Cu+, Ti3+ or Cr2+ can be successfully employed, but most commonly, Fe2+ cations are used.
The contribution of this paper is an adding of Fe2+ ions by dissolution of the electrodes. The advantage of this method consists of indirect adding of Fe+2 from solid phase which eliminates the need of dosing of the Fe in the form of the solution (FeSO4, FeCl2, FeCl3, Fe2(SO4)3 …) causing secondary pollution and an increase of salinity. This technology avoids unnecessary salts addition essential in cases, with problems of high salinity of the wastewater. To realise this process in the industrial scale, profound knowledge of the electrocoagulation and/or electroflotation is indispensable, especially for scale-up. This paper brings knowledge about the electrochemical background and technological approach for successful design for required volume flow. Based on our results, some details of suitable reactor types and its scale-up is presented in brief overview revealing suitability for selected cases.
