Treatment of dye containing colored index acid yellow 36 by electrocoagulation using iron electrodes

ABSTRACT

The removal of pollutants from effluents by electrocoagulation has become an attractive method in recent years. This paper deals with the batch removal of the reactive textile dye Colored Index [C. I.]. Acid yellow 36 from an aqueous medium by the electrocoagulation method using iron electrodes. The effects of electrolyte concentration, initial pH, current density, electrode area, interelectrode distance, dye concentration, and treatment time on the decolorization efficiency have been investigated. Iron hydroxypolymeric species formed during an earlier stage of the operation efficiently remove dye molecules by adsorption and precipitation, and in a subsequent stage, Fe[OH]3 flocs trap colloidal precipitates and make solid liquid separation easier during the flotation stage. These stages of electrocoagulation must be optimized to design an economically feasible electrocoagulation process. The increase of current density up to 127.8 A/m2 enhanced the color removal efficiency. Our results showed that the optimum electrolysis time was 6 min. The optimum pH was determined 8. It was also found that the color removal% [R.P.%] with increasing of dye concentration, decrease. The optimum amount of electrolyte [NaCl] was found to be 8 g/l when the dye concentration was 50 mg/l