Color removal from dye-containing aqueous solutions by electrooxidation
Sanaa El Aggadi, Zoubida El Abbassi, Abderrahim El Hourch
Abstract
ABSTRACT This study investigated the electrochemical decolorization of Reactive Blue 21 (RB21) dye in an aqueous solution on a platinum (Pt) electrode. The influence of operating variables on decolorization efficiency was studied including supporting electrolyte (Na 2 SO 4 and KCl), current density (range 50–300 mA cm −2 ) and initial pH (between 3–11). Within 20 min of electrochemical treatment, about 99.94% of the color was removed from the KCl and 39.90% from the Na 2 SO 4 solutions. This degradation efficiency in the KCl solutions can be attributed to indirect electrochemical oxidation, where, in the presence of chlorides, the electrolyte generates strongly oxidizing spеcies, which enhance the efficiеncy of the treatment at the Pt electrode. Optimal operating conditions to achieve an efficiency greater than 99% for the removal of the RB21 dye (0.1 mM) were a current density = 100 mA cm −2 , an initial pH between 3 and 11 during the electrolysis time = 20 min in KCl solution at room temperature (20°C).