An experimental study of indigo carmine removal from aqueous solution by electrocoagulation

This paper presents an experimental study on the removal of Indigo Carmine dye from aqueous solutions using a batch stirred electrocoagulation reactor. The experimental tests were carried out in a discontinuous system provided with steel electrodes. The main purpose was to investigate the effects of the operating parameters, such as pH, initial concentration, electrolysis duration, current density, and electrolyte support concentration, on the treatment of a synthetic wastewater containing indigo carmine dye in the batch electrocoagulation process. The batch electrocoagulation reactor was operated at various current densities ranging from 5.46 to 54.57 A.m(-2). Initial concentration of the dye was ranged between 25 and 100 mg.L(-1). The initial value of pH was varied from 5 to 9, while the concentration of the electrolyte support ranged from 0.2 to 4.5 g.L(-1) It was shown that pH control during electrocoagulation process is not beneficial in case of Indigo Carmine removal. The values of the rate constant were determined according to the pseudo first-order kinetic model that fits the experimental data. The highest rate constants were achieved for a current density of 54.57 A.m(-2), an initial dye concentration of 25 mg.L(-1), an initial pH of 8, and a background electrolyte concentration of 77 mM. (C) 2011 Elsevier B.V. All rights reserved.