Removal of basic dye solutions by electrocoagulation: study of efficiency of decolorization and COD abatement of malachite green solution

In this study, the decolorization of strong colored solutions containing the reactive textile dye by electrocoagulation was investigated. The electrocoagulation process was developed to overcome the drawbacks of conventional wastewater treatment technologies. This process is very effective in removing organic pollutants including dye stuff wastewater and chemical oxygen demand (COD) abatement of a synthetic textile wastewater using metallic electrodes and allows for the reduction of sludge generation. The experiment were carried out in order to investigate the efficiency of decolorization of a solution containing an basic dye (malachite green) by electrocoagulation (EC) in order to compare the efficiency of different electrode connections for color removal. Current density, time of electrolysis and pH of the solution were the variables that most influenced color removal. The results showed that the color was effectively removed with a removal yield of higher than 80%. The electrolysis time was 5 min for wastewater with a COD of 40-200 mg/L and a dye concentration of <150 mg/L. The optimum conditions were as follows: pH range of 3-5.3, residence time of 14 min, current density of up to 60-80 A M-2 supporting electrolyte (NaCl) concentration of 4 g/L. Under these conditions, the COD abatement was also higher than 60%. The dominant mechanism of color and COD removals from reactive dye bath effluent by developed method seemed to be coagulation and adsorption.

کلیدواژه ها:

Basic Dye ، COD ، Decolorization ، Electrocoagulation ، Malachite Green