The role of dye molecular weight on the decolorization performance of the electrocoagulation

Comparative results of color removal performances of Reactive Blue 198 (RB198), Reactive Yellow (RY145) and Reactive Blue 19 (RB19) by electrocoagulation process are presented. Our primary objective was to investigate whether the dye molecular weight affects color removal performance. Dye removal costs of each dye were calculated and compared. Experiments were performed at current densities of 1.04, 2.08, 4.17 and 10.42 A/m² in electrocoagulation (EC) reactor with aluminum electrodes connected parallel monopolar configuration. Laboratory-scale experiments were run in batch mode with 0.5 L synthetic dye solution volume and 50 mg/L initial dye concentration. Results showed that the color removal efficiencies were directly influenced by the molecular weight of the dyes. The color removal efficiency of the dye with the greatest molecular weight (RB198) was the highest, whereas the color removal efficiency of the dye with the smallest molecular weight (RB19) was the lowest. Moreover, results indicated that the operating cost of RB198 was significantly lower (2.91 $ per kg dye removed) than RY145 (6.61 $ per kg dye removed) and RB19 ($6.72 per kg dye removed) at a current density of 4.17 A/m².