Abstract
Coagulation is one of the most important physiochemical operations used in wastewater treatment and can be achieved by chemical or electrical means. In this study, electrocoagulation using sacrificial iron electrodes which produce Fe(OH)$_2$has been examined with laboratory-formulated dye wastewater containing C.I. Acid Red 106 (azo type) and C.I. Acid Green 25 (anthraquinone type) and it has proven to be very effective in color removal. A series of experiments were conducted to establish the parameters influencing the efficiency in electrochemical color removal. Applied voltage, number and shape of eletrodes, eletrode distance, treatment time as well as the pH of wastewater are estimated to be important system parameters. Color removal increases with plate-shaped electrode rather than circular-shaped one, as the number of electrodes, voltage, and treatment time increase and distance between electrodes decreases. This phenomenon can be explained in terms of the amount of iron generated during the treatment. UV spectra of treated dye solutions indicate that color removal mechanism is likely to be primarily adsorption of dyes on electrochemically generated ferrous hydroxide with a little dye degradation observed only in the last stage of treatment.
