ELECTRO-FENTON REMOVAL OF THE CATIONIC DYE BASIC BLUE 3 BY USING CARBON FELT CATHODE

摘要

In this study, we used the electro-Fenton technology for the removal of a cationic dye, the Basic Blue 3 (BB3), from aqueous medium. This technology uses the Fenton reaction as the source of hydroxyl radicals, in which the Fenton reagent, a mixture of H_2O_2 and Fe~(2+), is produced electrochemically and regenerated throughout the process. The formed hydroxyl radicals led to the oxidative degradation of BB3 until its total mineralization. The decay of BB3 and the evolution of its oxidation products during electrolysis were monitored by high performance liquid chromatography. The absolute rate constant of the BB3 hydroxylation reaction has been determined as (2.61 ± 0.06) × 10~9 M~(-1) s~(-1) by using the competition kinetic method. The effect of the applied current on the BB3 removal rate was examined. The optimal current value for the mineralization of BB3 aqueous solution was found as 300 mA. It was also observed that the catalyst (Fe~(3+)) concentrations more than 0.2 mM have a negative effect on the mineralization rate of BB3. The mineralization of BB3 aqueous solution was followed by total organic carbon measurements. The mineralization ratio reached up to 98%. The degradation reaction intermediates such as aromatic compounds, carboxylic acids and inorganic ions were identified and a mineralization pathway was proposed.