Investigation of the Electrocoagulation Treatment of Cotton Blue Dye Solution using Aluminium Electrodes

This study was performed to investigate the variables that influence the removal efficiency of an acid dye, i.e., cotton blue (CB) (chemical name: aniline blue WS) dye, from aqueous solution by an electrocoagulation (EC) technique. Batch EC studies were performed using aluminum electrodes to evaluate the influences of various experimental parameters, i.e., initial pH (pH(0)): 3-11, electrolysis time (t): 0-30 min, initial concentration (C-0): 100-1000 mg/L, electrode gap (g): 0.5-1.3 cm, number of electrodes (N): 4 - 10, and applied voltage (V-ap): 7-11 V, on the removal of CB dye. The optimum values of pH(0), V-ap and t for CB removal were found to be 6.0, 11 V and 15 min, respectively. The removal efficiency increased with decreasing values of C-0 and g. For a CB solution having C-0 = 100 mg/L, 97% removal efficiency was obtained at the optimized conditions. It was found that the EC sludge can be dried and thermally degraded. The bottom ash obtained after its combustion can be blended with cementitious mixtures. This approach for EC sludge disposal ensures energy recovery along with safe disposal of the EC sludge.